Hopkins with SPHERES RINGS

NASA Image and Video Library

2013-11-04

ISS037-E-025868 (4 Nov. 2013) --- In the International Space Station?s Kibo laboratory, NASA astronaut Michael Hopkins, Expedition 37 flight engineer, conducts a session with a pair of bowling-ball-sized free-flying satellites known as Synchronized Position Hold, Engage, Reorient, Experimental Satellites, or SPHERES. Surrounding the two SPHERES mini-satellites is ring-shaped hardware known as the Resonant Inductive Near-field Generation System, or RINGS. SPHERES-RINGS seeks to demonstrate wireless power transfer between satellites at a distance for enhanced operations.

DOD SPHERES-RINGS Test Session

NASA Image and Video Library

2013-11-04

ISS037-E-025915 (4 Nov. 2013) --- In the International Space Station?s Kibo laboratory, NASA astronaut Michael Hopkins, Expedition 37 flight engineer, conducts a session with a pair of bowling-ball-sized free-flying satellites known as Synchronized Position Hold, Engage, Reorient, Experimental Satellites, or SPHERES. Surrounding the two SPHERES mini-satellites is ring-shaped hardware known as the Resonant Inductive Near-field Generation System, or RINGS. SPHERES-RINGS seeks to demonstrate wireless power transfer between satellites at a distance for enhanced operations.

Hopkins with SPHERES RINGS

NASA Image and Video Library

2013-11-04

ISS037-E-025866 (4 Nov. 2013) --- In the International Space Station?s Kibo laboratory, NASA astronaut Michael Hopkins, Expedition 37 flight engineer, conducts a session with a pair of bowling-ball-sized free-flying satellites known as Synchronized Position Hold, Engage, Reorient, Experimental Satellites, or SPHERES. Surrounding the two SPHERES mini-satellites is ring-shaped hardware known as the Resonant Inductive Near-field Generation System, or RINGS. SPHERES-RINGS seeks to demonstrate wireless power transfer between satellites at a distance for enhanced operations.

Hopkins with SPHERES RINGS

NASA Image and Video Library

2013-11-04

ISS037-E-025872 (4 Nov. 2013) --- In the International Space Station?s Kibo laboratory, NASA astronaut Michael Hopkins, Expedition 37 flight engineer, conducts a session with a pair of bowling-ball-sized free-flying satellites known as Synchronized Position Hold, Engage, Reorient, Experimental Satellites, or SPHERES. Surrounding the two SPHERES mini-satellites is ring-shaped hardware known as the Resonant Inductive Near-field Generation System, or RINGS. SPHERES-RINGS seeks to demonstrate wireless power transfer between satellites at a distance for enhanced operations.

Hopkins with SPHERES RINGS

NASA Image and Video Library

2013-11-04

ISS037-E-025879 (4 Nov. 2013) --- In the International Space Station?s Kibo laboratory, NASA astronaut Michael Hopkins, Expedition 37 flight engineer, conducts a session with a pair of bowling-ball-sized free-flying satellites known as Synchronized Position Hold, Engage, Reorient, Experimental Satellites, or SPHERES. Surrounding the two SPHERES mini-satellites is ring-shaped hardware known as the Resonant Inductive Near-field Generation System, or RINGS. SPHERES-RINGS seeks to demonstrate wireless power transfer between satellites at a distance for enhanced operations.

Automated synthesis of a library of triazolated 1,2,5-thiadiazepane 1,1-dioxides via a double aza-Michael strategy.

PubMed

Zang, Qin; Javed, Salim; Hill, David; Ullah, Farman; Bi, Danse; Porubsky, Patrick; Neuenswander, Benjamin; Lushington, Gerald H; Santini, Conrad; Organ, Michael G; Hanson, Paul R

2012-08-13

The construction of a 96-member library of triazolated 1,2,5-thiadiazepane 1,1-dioxides was performed on a Chemspeed Accelerator (SLT-100) automated parallel synthesis platform, culminating in the successful preparation of 94 out of 96 possible products. The key step, a one-pot, sequential elimination, double-aza-Michael reaction, and [3 + 2] Huisgen cycloaddition pathway has been automated and utilized in the production of two sets of triazolated sultam products.

Automated Synthesis of a Library of Triazolated 1,2,5-Thiadiazepane 1,1-Dioxides via a Double aza-Michael Strategy

PubMed Central

Zang, Qin; Javed, Salim; Hill, David; Ullah, Farman; Bi, Danse; Porubsky, Patrick; Neuenswander, Benjamin; Lushington, Gerald H.; Santini, Conrad; Organ, Michael G.; Hanson, Paul R.

2013-01-01

The construction of a 96-member library of triazolated 1,2,5-thiadiazepane 1,1-dioxides was performed on a Chemspeed Accelerator (SLT-100) automated parallel synthesis platform, culminating in the successful preparation of 94 out of 96 possible products. The key step, a one-pot, sequential elimination, double-aza-Michael reaction, and [3+2] Huisgen cycloaddition pathway has been automated and utilized in the production of two sets of triazolated sultam products. PMID:22853708

Topics in the Sequential Design of Experiments

DTIC Science & Technology

1992-03-01

decision , unless so designated by other documentation. 12a. DISTRIBUTION /AVAILABIIUTY STATEMENT 12b. DISTRIBUTION CODE Approved for public release...3 0 1992 D 14. SUBJECT TERMS 15. NUMBER OF PAGES12 Design of Experiments, Renewal Theory , Sequential Testing 1 2. PRICE CODE Limit Theory , Local...distributions for one parameter exponential families," by Michael Woodroofe. Stntca, 2 (1991), 91-112. [6] "A non linear renewal theory for a functional of

Organobase catalyzed 1,4-conjugate addition of 4-hydroxycoumarin on chalcones: Synthesis, NMR and single-crystal X-ray diffraction studies of novel warfarin analogues

NASA Astrophysics Data System (ADS)

Talhi, Oualid; Fernandes, José A.; Pinto, Diana C. G. A.; Almeida Paz, Filipe A.; Silva, Artur M. S.

2015-08-01

The synthesis of a new series of warfarin analogues by convenient organobase catalyzed 1,4-conjugate addition of 4-hydroxycoumarin to chalcone derivatives is described. 1H NMR spectroscopy evidenced the presence of a predominant acyclic open-form together with the cyclic hemiketal tautomers of the resulting Michael adducts. The acyclic open-form has been unequivocally proved by single-crystal X-ray diffraction analysis. The use of the B ring ortho-hydroxychalcone synthons in this reaction has led to a diastereoselective synthesis of warfarin bicyclo[3.3.1]nonane ketal derivatives.

An exceptionally potent inducer of cytoprotective enzymes: elucidation of the structural features that determine inducer potency and reactivity with Keap1.

PubMed

Dinkova-Kostova, Albena T; Talalay, Paul; Sharkey, John; Zhang, Ying; Holtzclaw, W David; Wang, Xiu Jun; David, Emilie; Schiavoni, Katherine H; Finlayson, Stewart; Mierke, Dale F; Honda, Tadashi

2010-10-29

The Keap1/Nrf2/ARE pathway controls a network of cytoprotective genes that defend against the damaging effects of oxidative and electrophilic stress, and inflammation. Induction of this pathway is a highly effective strategy in combating the risk of cancer and chronic degenerative diseases, including atherosclerosis and neurodegeneration. An acetylenic tricyclic bis(cyano enone) bearing two highly electrophilic Michael acceptors is an extremely potent inducer in cells and in vivo. We demonstrate spectroscopically that both cyano enone functions of the tricyclic molecule react with cysteine residues of Keap1 and activate transcription of cytoprotective genes. Novel monocyclic cyano enones, representing fragments of rings A and C of the tricyclic compound, reveal that the contribution to inducer potency of the ring C Michael acceptor is much greater than that of ring A, and that potency is further enhanced by spatial proximity of an acetylenic function. Critically, the simultaneous presence of two cyano enone functions in rings A and C within a rigid three-ring system results in exceptionally high inducer potency. Detailed understanding of the structural elements that contribute to the reactivity with the protein sensor Keap1 and to high potency of induction is essential for the development of specific and selective lead compounds as clinically relevant chemoprotective agents.

Design, synthesis and cellular metabolism study of 4'-selenonucleosides.

PubMed

Yu, Jinha; Sahu, Pramod K; Kim, Gyudong; Qu, Shuhao; Choi, Yoojin; Song, Jayoung; Lee, Sang Kook; Noh, Minsoo; Park, Sunghyouk; Jeong, Lak Shin

2015-01-01

4'-seleno-homonucleosides were synthesized as next-generation nucleosides, and their cellular phosphorylation was studied to confirm the hypothesis that bulky selenium atom can sterically hinder the approach of cellular nucleoside kinase to the 5'-OH for phosphorylation. 4'-seleno-homonucleosides (n = 2), with one-carbon homologation, were synthesized through a tandem seleno-Michael addition-SN2 ring cyclization. LC-MS analysis demonstrated that they were phosphorylated by cellular nucleoside kinases, resulting in anticancer activity. The bulky selenium atom played a key role in deciding the phosphorylation by cellular nucleoside kinases. [Formula: see text].

Formation of polycyclic lactones through a ruthenium-catalyzed ring-closing metathesis/hetero-Pauson-Khand reaction sequence.

PubMed

Finnegan, David F; Snapper, Marc L

2011-05-20

Processes that form multiple carbon-carbon bonds in one operation can generate molecular complexity quickly and therefore be used to shorten syntheses of desirable molecules. We selected the hetero-Pauson-Khand (HPK) cycloaddition and ring-closing metathesis (RCM) as two unique carbon-carbon bond-forming reactions that could be united in a tandem ruthenium-catalyzed process. In doing so, complex polycyclic products can be obtained in one reaction vessel from acyclic precursors using a single ruthenium additive that can catalyze sequentially two mechanistically distinct transformations.

Straightforward Entry toward Highly Substituted 2,3-Dihydrobenz[ b]oxepines by Ring Expansion of Benzopyryliums with Donor-Acceptor Diazo Compounds.

PubMed

Courant, Thibaut; Pasco, Morgane; Lecourt, Thomas

2018-05-04

Ylide-type reactivity of diazo compounds is exploited in a new way to prepare benzo[ b]oxepines thanks to the formation of three chemical bonds and two contiguous and highly substituted stereocenters in a single pot. This cationic reaction cascade first involves addition of a donor-acceptor-substituted diazo compound to a benzopyrylium. Selective 1,2 migration of the endocyclic C-C bond then results in a ring-expansion and generates a second oxocarbenium that is trapped by a nucleophile added sequentially.

Identifying the Tautomeric Form of a Deoxyguanosine-Estrogen Quinone Intermediate.

PubMed

Stack, Douglas E

2015-09-10

Mechanistic insights into the reaction of an estrogen o-quinone with deoxyguanosine has been further investigated using high level density functional calculations in addition to the use of 4-hyroxycatecholestrone (4-OHE₁) regioselectivity labeled with deuterium at the C1-position. Calculations using the M06-2X functional with large basis sets indicate the tautomeric form of an estrogen-DNA adduct present when glycosidic bonds cleavage occurs is comprised of an aromatic A ring structure. This tautomeric form was further verified by use of deuterium labelling of the catechol precursor use to form the estrogen o-quinone. Regioselective deuterium labelling at the C1-position of the estrogen A ring allows discrimination between two tautomeric forms of a reaction intermediate either of which could be present during glycosidic bond cleavage. HPLC-MS analysis indicates a reactive intermediate with a m/z of 552.22 consistent with a tautomeric form containing no deuterium. This intermediate is consistent with a reaction mechanism that involves: (1) proton assisted Michael addition; (2) re-aromatization of the estrogen A ring; and (3) glycosidic bond cleavage to form the known estrogen-DNA adduct, 4-OHE₁-1-N7Gua.

Divergent Total Syntheses of (-)-Huperzine Q, (+)-Lycopladine B, (+)-Lycopladine C, and (-)-4-epi-Lycopladine D.

PubMed

Hong, Benke; Hu, Dachao; Wu, Jinbao; Zhang, Jing; Li, Houhua; Pan, Yingming; Lei, Xiaoguang

2017-07-04

We report herein our synthetic efforts towards the divergent syntheses of (-)-huperzine Q (1), (+)-lycopladine B (2), (+)-lycopladine C (3), and (-)-lycopladine D (4). The 10-step total synthesis of (-)-huperzine Q (1) and the first total syntheses of (+)-lycopladines B (2) and C (3) were accomplished through a series of cascade reactions. Our approach involved a Michael addition/aldol/intramolecular C-alkylation sequence to forge the 6/9 spirocycle ring, and this was followed by an ethylene-accelerated carbonyl-olefin metathesis to construct the common 6/5/9 ring system. Finally, late-stage enamine bromofunctionalization enabled us to access (-)-huperzine Q (1), (+)-lycopladine B (2), and (+)-lycopladine C (3), and a tandem C4-epimerization/retro-Claisen condensation furnished (-)-4-epi-lycopladine D (63). © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Unsteady Aerodynamic Interaction in a Closely Coupled Turbine Consistent with Contra-Rotation

DTIC Science & Technology

2014-08-01

data on the blade required three instrumentation patches due to slip ring channel limitations. TRF blowdowns designated as experiments 280100...measurements from sensors on the rotating hardware due to slip ring limitations. The experimental data was compared to time-accurate simulations modeling...AFRL-RQ-WP-TR-2014-0195 UNSTEADY AERODYNAMIC INTERACTION IN A CLOSELY COUPLED TURBINE CONSISTENT WITH CONTRA-ROTATION Michael Kenneth

Synthesis of a stationary phase based on silica modified with branched octadecyl groups by Michael addition and photoinduced thiol-yne click chemistry for the separation of basic compounds.

PubMed

Huang, Guang; Ou, Junjie; Wang, Hongwei; Ji, Yongsheng; Wan, Hao; Zhang, Zhang; Peng, Xiaojun; Zou, Hanfa

2016-04-01

A novel silica-based stationary phase with branched octadecyl groups was prepared by the sequential employment of the Michael addition reaction and photoinduced thiol-yne click chemistry with 3-aminopropyl-functionalized silica microspheres as the initial material. The resulting stationary phase denoted as SiO2 -N(C18)4 was characterized by elemental analysis, FTIR spectroscopy and Raman spectroscopy, demonstrating the existence of branched octadecyl groups in silica microspheres. The separations of benzene homologous compounds, acid compounds and amine analogues were conducted, demonstrating mixed-mode separation mechanism on SiO2 -N(C18)4 . Baseline separation of basic drugs mixture was acquired with the mobile phase of acetonitrile/H2 O (5%, v/v). SiO2 -N(C18)4 was further applied to separate Corydalis yanhusuo Wang water extracts, and more baseline separation peaks were obtained for SiO2 -N(C18)4 than those on Atlantis dC18 column. It can be expected that this new silica-based stationary phase will exhibit great potential in the analysis of basic compounds. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

3β,5α,6β-Trihy­droxy­androstan-17-one

PubMed Central

Andrade, L.C.R.; de Almeida, M.J.B.M.; Paixão, J.A.; Carvalho, J.F.S.; Sá e Melo, M.L.

2011-01-01

The title compound, C19H30O4, is an androstan-17-one derivative synthesized from the dehydro­epiandrosterone through a sequential addition of an oxidant, followed by a trans-diaxial opening of the epoxide generated, with Bi(OTf)3 (OTf is trifluoro­methane­sulfonate). The six-membered rings have a slightly flattened chair conformation, while the five-membered ring adopts a 14-α envelope conformation. All rings are trans fused. In the crystal, the mol­ecules are connected by O—H⋯O hydrogen bonds involving the hydroxyl and carbonyl groups, forming a three-dimensional network. A quantum mechanical ab initio Roothan Hartree–Fock calculation of the free mol­ecule gives bond lengths, valency angles and ring torsion angles of the free molecule at equilibrium geometry (energy minimum) close to the experimental values. PMID:21754383

Asymmetric processing of a substrate protein in sequential allosteric cycles of AAA+ nanomachines

NASA Astrophysics Data System (ADS)

Kravats, Andrea N.; Tonddast-Navaei, Sam; Bucher, Ryan J.; Stan, George

2013-09-01

Essential protein quality control includes mechanisms of substrate protein (SP) unfolding and translocation performed by powerful ring-shaped AAA+ (ATPases associated with various cellular activities) nanomachines. These SP remodeling actions are effected by mechanical forces imparted by AAA+ loops that protrude into the central channel. Sequential intra-ring allosteric motions, which underlie repetitive SP-loop interactions, have been proposed to comprise clockwise (CW), counterclockwise (CCW), or random (R) conformational transitions of individual AAA+ subunits. To probe the effect of these allosteric mechanisms on unfoldase and translocase functions, we perform Langevin dynamics simulations of a coarse-grained model of an all-alpha SP processed by the single-ring ClpY ATPase or by the double-ring p97 ATPase. We find that, in all three allosteric mechanisms, the SP undergoes conformational transitions along a common set of pathways, which reveals that the active work provided by the ClpY machine involves single loop-SP interactions. Nevertheless, the rates and yields of SP unfolding and translocation are controlled by mechanism-dependent loop-SP binding events, as illustrated by faster timescales of SP processing in CW allostery compared with CCW and R allostery. The distinct efficacy of allosteric mechanisms is due to the asymmetric collaboration of adjacent subunits, which involves CW-biased structural motions of AAA+ loops and results in CW-compatible torque applied onto the SP. Additional simulations of mutant ClpY rings, which render a subset of subunits catalytically-defective or reduce their SP binding affinity, reveal that subunit-based conformational transitions play the major role in SP remodeling. Based on these results we predict that the minimally functional AAA+ ring includes three active subunits, only two of which are adjacent.

Surface Modified Particles By Multi-Step Michael-Type Addition And Process For The Preparation Thereof

DOEpatents

Cook, Ronald Lee; Elliott, Brian John; Luebben, Silvia DeVito; Myers, Andrew William; Smith, Bryan Matthew

2005-05-03

A new class of surface modified particles and a multi-step Michael-type addition surface modification process for the preparation of the same is provided. The multi-step Michael-type addition surface modification process involves two or more reactions to compatibilize particles with various host systems and/or to provide the particles with particular chemical reactivities. The initial step comprises the attachment of a small organic compound to the surface of the inorganic particle. The subsequent steps attach additional compounds to the previously attached organic compounds through reactive organic linking groups. Specifically, these reactive groups are activated carbon—carbon pi bonds and carbon and non-carbon nucleophiles that react via Michael or Michael-type additions.

Origin of Second-Harmonic Generation Enhancement in Optical Split-Ring Resonators

DTIC Science & Technology

2012-05-15

Scalora , David R. Smith Duke University 2200 West Main Street Suite 710 Durham, NC 27705 -4010 REPORT DOCUMENTATION PAGE b. ABSTRACT UU c. THIS PAGE...harmonic generation enhancement in optical split-ring resonators Cristian Ciracı̀,1,* Ekaterina Poutrina,1 Michael Scalora ,2 and David R. Smith1 1Center for...11098-0121/2012/85(20)/201403(5) ©2012 American Physical Society RAPID COMMUNICATIONS CIRACÌ, POUTRINA, SCALORA , AND SMITH PHYSICAL REVIEW B 85

Reconsidering Division Cavalry Squadrons

DTIC Science & Technology

2017-05-25

mechanized cavalry against German, and to a lesser extent, Japanese combined arms forces cemented its status as a distinctive sub-branch in its rapidly...Integration Center, TRADOC, 1 June 2016 Mahler, Michael D. Ringed in Steel : Armored Cavalry, Vietnam 1967-68. Novato, CA: Presidio Press, 1986

Construction of divergent fused heterocycles via an acid-promoted intramolecular ipso-Friedel-Crafts alkylation of phenol derivatives.

PubMed

Yokosaka, Takuya; Shiga, Naoki; Nemoto, Tetsuhiro; Hamada, Yasumasa

2014-05-02

Two different cascade cyclization processes were developed using aryl group-substituted propargyl alcohol derivatives with a p-hydroxybenzylamine unit as common substrates. Using TFA as an acid promoter, an intramolecular ipso-Friedel-Crafts alkylation of phenol derivatives, formation of an iminium cation via a rearomatization-promoted C-C bond cleavage, an aza-Prins reaction, and a 6-membered ring formation proceeded sequentially, producing a variety of fused-tricyclic dihydroquinoline derivatives in 45-99% yield. In addition, a one-pot sequential silver acetate-catalyzed hydroamination/etherification-acid-promoted skeletal rearrangement was examined using the same series of substrates, affording fused-tricyclic indole/benzofuran derivatives in 66-89% yield.

Starch functionalized biodegradable semi-IPN as a pH-tunable controlled release platform for memantine.

PubMed

Ganguly, Sayan; Maity, Tushar; Mondal, Subhadip; Das, Poushali; Das, Narayan C

2017-02-01

Sequentially prepared semi-interpenetrating polymer network (semi-IPN) has been developed here via Michael type addition of acrylic acid (AA) and 2-acrylamido-2-methylpropane sulfonic acid (AMPS) on to starch. The semi-IPN hydrogel have proficiency in fast water imbibition towards gel network and swelling tunable character with pH alteration in ambient condition. The synthesized gel has been characterized by Fourier transformed infrared spectroscopy (FTIR) to confirm Michael type grafting of monomers on to starch. The surface morphology, observed from Scanning Electron Microscopy (SEM) exhibited corrugated rough surface on hydrogel which enhances the fast water uptake feature by anomalous Fickian case II diffusion mechanism. Grafting reaction also improves its thermal stability which has been confirmed by thermogravimetric analysis (TGA). Biodegradation study with hen egg lysozyme medium reveals the accelerated enzymatic scission of the starch backbone and progressive mass loss. Degradation of the hydrogel around 60% of its primary mass has been observed within 7days. The physicochemical characterizations of this hydrogel suggest this as a promising pH-tunable, biodegradable candidate for control drug delivery vehicle. Copyright © 2016 Elsevier B.V. All rights reserved.

Preparation of Bottlebrush Polymers via a One-Pot Ring-Opening Polymerization (ROP) and Ring-Opening Metathesis Polymerization (ROMP) Grafting-Through Strategy.

PubMed

Radzinski, Scott C; Foster, Jeffrey C; Matson, John B

2016-04-01

Bottlebrush polymers are synthesized using a tandem ring-opening polymerization (ROP) and ring-opening metathesis polymerization (ROMP) strategy. For the first time, ROP and ROMP are conducted sequentially in the same pot to yield well-defined bottlebrush polymers with molecular weights in excess of 10(6) Da. The first step of this process involves the synthesis of a polylactide macromonomer (MM) via ROP of d,l-lactide initiated by an alcohol-functionalized norbornene. ROMP grafting-through is then carried out in the same pot to produce the bottlebrush polymer. The applicability of this methodology is evaluated for different MM molecular weights and bottlebrush backbone degrees of polymerization. Size-exclusion chromatographic and (1)H NMR spectroscopic analyses confirm excellent control over both polymerization steps. In addition, bottlebrush polymers are imaged using atomic force microscopy and stain-free transmission electron microscopy on graphene oxide. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Direct Synthesis of Medium-Bridged Twisted Amides via a Transannular Cyclization Strategy

PubMed Central

Szostak, Michal; Aubé, Jeffrey

2009-01-01

The sequential RCM to construct a challenging medium-sized ring followed by a transannular cyclization across a medium-sized ring delivers previously unattainable twisted amides from simple acyclic precursors. PMID:19708701

TRIGGERED STAR FORMATION SURROUNDING WOLF-RAYET STAR HD 211853

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu Tie; Wu Yuefang; Zhang Huawei

The environment surrounding Wolf-Rayet (W-R) star HD 211853 is studied in molecular, infrared, as well as radio, and H I emission. The molecular ring consists of well-separated cores, which have a volume density of 10{sup 3} cm{sup -3} and kinematic temperature {approx}20 K. Most of the cores are under gravitational collapse due to external pressure from the surrounding ionized gas. From the spectral energy distribution modeling toward the young stellar objects, the sequential star formation is revealed on a large scale in space spreading from the W-R star to the molecular ring. A small-scale sequential star formation is revealed towardmore » core 'A', which harbors a very young star cluster. Triggered star formations are thus suggested. The presence of the photodissociation region, the fragmentation of the molecular ring, the collapse of the cores, and the large-scale sequential star formation indicate that the 'collect and collapse' process functions in this region. The star-forming activities in core 'A' seem to be affected by the 'radiation-driven implosion' process.« less

Total synthesis and biological activity of the proposed structure of phaeosphaeride A.

PubMed

Chatzimpaloglou, Anthoula; Yavropoulou, Maria P; Rooij, Karien E; Biedermann, Ralf; Mueller, Uwe; Kaskel, Stefan; Sarli, Vasiliki

2012-11-02

The total synthesis of the structure assigned to the natural product phaeosphaeride A 1a was accomplished. The key steps involve the addition of vinyllithium reagent 7 to the acetonide-protected aldehyde 8 to access the carbon backbone of 1a, the introduction of the methoxylamino group followed by intramolecular hetero-Michael cyclization, and methanol elimination to form the dihydropyran ring. In this study, both enantiomers of 1a were synthesized and tested for biological activity. Preliminary results showed that (6R,7R,8R)-1a and (6S,7S,8S)-1a inhibit STAT3-dependent transcriptional activity in a dose-dependent manner and exhibit antiproliferative properties in breast (MDA-MB-231) and pancreatic (PANC-1) cancer cells.

Organocatalytic aza-Michael/retro-aza-Michael reaction: pronounced chirality amplification in aza-Michael reaction and racemization via retro-aza-Michael reaction.

PubMed

Cai, Yong-Feng; Li, Li; Luo, Meng-Xian; Yang, Ke-Fang; Lai, Guo-Qiao; Jiang, Jian-Xiong; Xu, Li-Wen

2011-05-01

A detailed experimental investigation of an aza-Michael reaction of aniline and chalcone is presented. A series of Cinchona alkaloid-derived organocatalysts with different functional groups were prepared and used in the aza-Michael and retro-aza-Michael reaction. There was an interesting finding that a complete reversal of stereoselectivity when a benzoyl group was introduced to the cinchonine and cinchonidine. The chirality amplification vs. time proceeds in the quinine-derived organocatalyst containing silicon-based bulky group, QN-TBS, -catalyzed aza-Michael reaction under solvent-free conditions. In addition, we have demonstrated for the first time that racemization was occurred in suitable solvents under mild conditions due to retro-aza-Michael reaction of the Michael adduct of aniline with chalcone. These indicate the equilibrium of retro-aza-Michael reaction and aza-Michael reaction produce the happening of chirality amplification in aza-Michael reaction and racemization via retro-aza-Michael reaction under different conditions, which would be beneficial to the development of novel chiral catalysts for the aza-Michael reactions. Copyright © 2011 Wiley-Liss, Inc.

Covalent Modifiers: A Chemical Perspective on the Reactivity of α,β-Unsaturated Carbonyls with Thiols via Hetero-Michael Addition Reactions.

PubMed

Jackson, Paul A; Widen, John C; Harki, Daniel A; Brummond, Kay M

2017-02-09

Although Michael acceptors display a potent and broad spectrum of bioactivity, they have largely been ignored in drug discovery because of their presumed indiscriminate reactivity. As such, a dearth of information exists relevant to the thiol reactivity of natural products and their analogues possessing this moiety. In the midst of recently approved acrylamide-containing drugs, it is clear that a good understanding of the hetero-Michael addition reaction and the relative reactivities of biological thiols with Michael acceptors under physiological conditions is needed for the design and use of these compounds as biological tools and potential therapeutics. This Perspective provides information that will contribute to this understanding, such as kinetics of thiol addition reactions, bioactivities, as well as steric and electronic factors that influence the electrophilicity and reversibility of Michael acceptors. This Perspective is focused on α,β-unsaturated carbonyls given their preponderance in bioactive natural products.

Postpolymerization Modifications of Alkene-Functional Polycarbonates for the Development of Advanced Materials Biomaterials.

PubMed

Thomas, Anthony W; Dove, Andrew P

2016-12-01

Functional aliphatic polycarbonates have attracted significant attention as materials for use as biomedical polymers in recent years. The incorporation of pendent functionality offers a facile method of modifying materials postpolymerization, thus enabling functionalities not compatible with ring-opening polymerization (ROP) to be introduced into the polymer. In particular, polycarbonates bearing alkene-terminated functional groups have generated considerable interest as a result of their ease of synthesis, and the wide range of materials that can be obtained by performing simple postpolymerization modifications on this functionality, for example, through radical thiol-ene addition, Michael addition, and epoxidation reactions. This review presents an in-depth appraisal of the methods used to modify alkene-functional polycarbonates postpolymerization, and the diversity of practical applications for which these materials and their derivatives have been used. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

"Anti-Michael addition" of Grignard reagents to sulfonylacetylenes: synthesis of alkynes.

PubMed

Esteban, Francisco; Boughani, Lazhar; García Ruano, José L; Fraile, Alberto; Alemán, José

2017-05-10

In this work, the addition of Grignard reagents to arylsulfonylacetylenes, which undergoes an "anti-Michael addition", resulting in their alkynylation under very mild conditions is described. The simplicity of the experimental procedure and the functional group tolerance are the main features of this methodology. This is an important advantage over the use of organolithium at -78 °C that we previously reported. Moreover, the synthesis of diynes and other examples showing functional group tolerance in this anti-Michael reaction is also presented.

Racemic hemiacetals as oxygen-centered pronucleophiles triggering cascade 1,4-addition/Michael reaction through dynamic kinetic resolution under iminium catalysis. Development and mechanistic insights† †Electronic supplementary information (ESI) available: Detailed experimental procedures and characterization of all new compounds, including copies of NMR spectra and HPLC chromatograms traces, computational details and Cartesian coordinates of all stationary points. CCDC 1525188 (4l), 1525189 (6a) and 1525190 (9a). For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c7sc00009j Click here for additional data file. Click here for additional data file.

PubMed Central

Orue, Ane; Uria, Uxue; Roca-López, David; Delso, Ignacio; Reyes, Efraím; Carrillo, Luisa

2017-01-01

2-Hydroxydihydropyran-5-ones behave as excellent polyfunctional reagents able to react with enals through oxa-Michael/Michael process cascade under the combination of iminium and enamine catalysis. These racemic hemiacetalic compounds are used as unconventional O-pronucleophiles in the initial oxa-Michael reaction, also leading to the formation of a single stereoisomer under a dynamic kinetic resolution (DKR) process. Importantly, by using β-aryl or β-alkyl substituted α,β-unsaturated substrates as initial Michael acceptors either kinetically or thermodynamically controlled diastereoisomers were formed with high stereoselection through the careful selection of the reaction conditions. Finally, a complete experimental and computational study confirmed the initially proposed DKR process during the catalytic oxa-Michael/Michael cascade reaction and also explained the kinetic/thermodynamic pathway operating in each case. PMID:28451356

Synthesis of the carbocyclic core of the cornexistins by ring-closing metathesis.

PubMed

Clark, J Stephen; Marlin, Frederic; Nay, Bastien; Wilson, Claire

2003-01-09

An advanced intermediate in the synthesis of the phytotoxins cornexistin and hydroxycornexistin has been synthesized. Sequential palladium-mediated sp(2)-sp(3) fragment coupling and ring-closing diene metathesis have been used to construct the nine-membered carbocyclic core found in the natural products. [reaction--see text

Covalent Modifiers: A Chemical Perspective on the Reactivity of α,β-Unsaturated Carbonyls with Thiols via Hetero-Michael Addition Reactions

PubMed Central

Jackson, Paul A.; Widen, John C.; Harki, Daniel A.; Brummond, Kay M.

2017-01-01

Although Michael acceptors display a potent and broad spectrum of bioactivity, they have largely been ignored in drug discovery because of their presumed indiscriminate reactivity. As such, a dearth of information exists relevant to the thiol reactivity of natural products and their analogs possessing this moiety. In the midst of recently approved acrylamide-containing drugs, it is clear that a good understanding of the hetero-Michael addition reaction and the relative reactivities of biological thiols with Michael acceptors under physiological conditions is needed for the design and use of these compounds as biological tools and potential therapeutics. This perspective provides information that will contribute to this understanding, such as kinetics of thiol addition reactions, bioactivities, as well as steric and electronic factors that influence the electrophilicity and reversibility of Michael acceptors. This perspective is focused on α,β-unsaturated carbonyls given their preponderance in bioactive natural products. PMID:27996267

Computational Study of the Aza-Michael Addition of the Flavonoid (+)-Taxifolin in the Inhibition of β-Amyloid Fibril Aggregation.

PubMed

Ginex, Tiziana; Trius, Marta; Luque, F Javier

2018-04-17

Inhibition of abnormal protein self-aggregation is an attractive strategy against amyloidogenic diseases, but has found limited success due to the complexity of protein self-assembly, the absence of fully reproducible aggregation assays, and the scarce knowledge of the inhibition mechanisms by small molecules. In this context, catechol-containing compounds may lead to covalent adducts with amyloid fibrils that interfere with the aggregation process. In particular, the covalent adduct formed between the oxidized form of (+)-taxifolin and an β-amyloid (Aβ42) suggests the involvement of a specific recognition motif that enables the chemical reaction with Aβ42. In this study, we have examined the mechanisms implicated in the aza-Michael addition of the o-quinone species of (+)-taxifolin with Aβ42 fibrils. The results support the binding of (+)-taxifolin to the hydrophobic groove delimited by the edges defined by Lys16 and Glu22 residues in the fibril. The chemical reaction proceeds through the nucleophilic attack of the deprotonated amino group of a Lys16 residue in a process activated by the interaction between the o-quinone ring with a vicinal Lys16 residue, as well as by a water-assisted proton transfer, which is the rate-limiting step of the reaction. This specific inhibition mechanism, which may explain the enhanced anti-aggregating activity of oxidized flavonoids compared to fresh compounds, holds promise for developing disease-modifying therapies. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Probing the Reactivity of Dimethylsulfoxonium Methylide with Conjugated and Nonconjugated Carbonyl Compounds: An Undergraduate Experiment Combining Synthesis, Spectral Analysis, and Mechanistic Discovery

ERIC Educational Resources Information Center

Ciaccio, James A.; Guevara, Elena L.; Alam, Rabeka; D'agrosa, Christina D.

2010-01-01

We introduce students to dimethylsulfoxonium methylide (DMSY) epoxidation of aryl and nonconjugated aliphatic aldehydes and ketones without revealing that DMSY cyclopropanates enones by Michael-initiated ring closure (MIRC). Each student performs the reaction of DMSY with one of nine carbonyl compounds, including four enones, and then analyzes the…

Synthesis and biological evaluation of new piplartine analogues as potent aldose reductase inhibitors (ARIs)

PubMed Central

Ramasubba Rao, Vidadala; Muthenna, Puppala; Shankaraiah, Gundeti; Akileshwari, Chandrasekhar; Hari Babu, Kothapalli; Suresh, Ganji; Suresh Babu, Katragadda; Chandra Kumar, Rotte Sateesh; Rajendra Prasad, Kothakonda; Ashok Yadav, Potharaju; Petrash, J. Mark; Bhanuprakash Reddy, Geereddy; Madhusudana Rao, Janaswamy

2013-01-01

As a continuation of our efforts directed towards the development of anti-diabetic agents from natural sources, piplartine was isolated from Piper chaba, and was found to inhibit recombinant human ALR2 with an IC50 of 160 µM. To improve the efficacy, a series of analogues have been synthesized by modification of the styryl/aromatic and heterocyclic ring functionalities of this natural product lead. All the derivatives were tested for their ALR2 inhibitory activity, and results indicated that adducts 3c, 3e and 2j prepared by the Michael addition of piplartine with indole derivatives displayed potent ARI activity, while the other compounds displayed varying degrees of inhibition. The active compounds were also capable of preventing sorbitol accumulation in human red blood cells. PMID:23124161

Reaching Higher Gamma in Ultracold Neutral Plasmas Through Disorder-Induced Heating Control

DTIC Science & Technology

2016-06-27

shielding ,” Phys. Rev. E 87, 033101 (2013) 4 Sequential ionization of ultracold plasma ions A simulation published in 2007 by Michael Murillo showed...AFRL-AFOSR-VA-TR-2017-0031 Reaching higher Gamma in ultracold neutral plasmas through disorder-induced heating control Scott Bergeson BRIGHAM YOUNG...TYPE Final Report 3. DATES COVERED (From - To) 01 June 2012 - 31 May 2016 4. TITLE AND SUBTITLE Reaching higher Gamma in ultracold neutral plasmas

Method for promoting Michael addition reactions

DOEpatents

Shah, Pankaj V.; Vietti, David E.; Whitman, David William

2010-09-21

Homogeneously dispersed solid reaction promoters having an average particle size from 0.01 .mu.m to 500 .mu.m are disclosed for preparing curable mixtures of at least one Michael donor and at least one Michael acceptor. The resulting curable mixtures are useful as coatings, adhesives, sealants and elastomers.

G-sequentially connectedness for topological groups with operations

NASA Astrophysics Data System (ADS)

Mucuk, Osman; Cakalli, Huseyin

2016-08-01

It is a well-known fact that for a Hausdorff topological group X, the limits of convergent sequences in X define a function denoted by lim from the set of all convergent sequences in X to X. This notion has been modified by Connor and Grosse-Erdmann for real functions by replacing lim with an arbitrary linear functional G defined on a linear subspace of the vector space of all real sequences. Recently some authors have extended the concept to the topological group setting and introduced the concepts of G-sequential continuity, G-sequential compactness and G-sequential connectedness. In this work, we present some results about G-sequentially closures, G-sequentially connectedness and fundamental system of G-sequentially open neighbourhoods for topological group with operations which include topological groups, topological rings without identity, R-modules, Lie algebras, Jordan algebras, and many others.

Double hetero-Michael addition of N-substituted hydroxylamines to quinone monoketals: synthesis of bridged isoxazolidines.

PubMed

Yin, Zhiwei; Zhang, Jinzhu; Wu, Jing; Liu, Che; Sioson, Kate; Devany, Matthew; Hu, Chunhua; Zheng, Shengping

2013-07-19

A general synthesis of bridged isoxazolidines from a double hetero-Michael addition of N-substituted hydroxylamines to quinone monoketals has been developed. The different addition order of N-benzylhydroxylamine and N-Boc hydroxylamine is also discussed. Moreover, the various functionalities in the isoxazolidine products allow facile derivatization.

Enantioselective Michael Addition of Pyrroles with Nitroalkenes in Aqueous Media Catalyzed by a Water-soluble Catalyst.

PubMed

Gui, Yang; Li, Yanan; Sun, Jianan; Zha, Zhenggen; Wang, Zhiyong

2018-06-11

A new water-soluble catalytic system were developed and therefor used in an enantioselective Michael addition of pyrroles with nitroalkenes in water to afford the nitroethylpyrrole derivatives with both excellent yields and ee values.

Chemistry and Biology of DNA Containing 1,N2-Deoxyguanosine Adducts of the α,β-Unsaturated Aldehydes Acrolein, Crotonaldehyde, and 4-Hydroxynonenal

PubMed Central

2009-01-01

The α,β-unsaturated aldehydes (enals) acrolein, crotonaldehyde, and trans-4-hydroxynonenal (4-HNE) are products of endogenous lipid peroxidation, arising as a consequence of oxidative stress. The addition of enals to dG involves Michael addition of the N2-amine to give N2-(3-oxopropyl)-dG adducts, followed by reversible cyclization of N1 with the aldehyde, yielding 1,N2-dG exocyclic products. The 1,N2-dG exocyclic adducts from acrolein, crotonaldehyde, and 4-HNE exist in human and rodent DNA. The enal-induced 1,N2-dG lesions are repaired by the nucleotide excision repair pathway in both Escherichia coli and mammalian cells. Oligodeoxynucleotides containing structurally defined 1,N2-dG adducts of acrolein, crotonaldehyde, and 4-HNE were synthesized via a postsynthetic modification strategy. Site-specific mutagenesis of enal adducts has been carried out in E. coli and various mammalian cells. In all cases, the predominant mutations observed are G→T transversions, but these adducts are not strongly miscoding. When placed into duplex DNA opposite dC, the 1,N2-dG exocyclic lesions undergo ring opening to the corresponding N2-(3-oxopropyl)-dG derivatives. Significantly, this places a reactive aldehyde in the minor groove of DNA, and the adducted base possesses a modestly perturbed Watson−Crick face. Replication bypass studies in vitro indicate that DNA synthesis past the ring-opened lesions can be catalyzed by pol η, pol ι, and pol κ. It also can be accomplished by a combination of Rev1 and pol ζ acting sequentially. However, efficient nucleotide insertion opposite the 1,N2-dG ring-closed adducts can be carried out only by pol ι and Rev1, two DNA polymerases that do not rely on the Watson−Crick pairing to recognize the template base. The N2-(3-oxopropyl)-dG adducts can undergo further chemistry, forming interstrand DNA cross-links in the 5′-CpG-3′ sequence, intrastrand DNA cross-links, or DNA−protein conjugates. NMR and mass spectrometric analyses indicate that the DNA interstand cross-links contain a mixture of carbinolamine and Schiff base, with the carbinolamine forms of the linkages predominating in duplex DNA. The reduced derivatives of the enal-mediated N2-dG:N2-dG interstrand cross-links can be processed in mammalian cells by a mechanism not requiring homologous recombination. Mutations are rarely generated during processing of these cross-links. In contrast, the reduced acrolein-mediated N2-dG peptide conjugates can be more mutagenic than the corresponding monoadduct. DNA polymerases of the DinB family, pol IV in E. coli and pol κ in human, are implicated in error-free bypass of model acrolein-mediated N2-dG secondary adducts, the interstrand cross-links, and the peptide conjugates. PMID:19397281

Polyphosphoester-Camptothecin Prodrug with Reduction-Response Prepared via Michael Addition Polymerization and Click Reaction.

PubMed

Du, Xueqiong; Sun, Yue; Zhang, Mingzu; He, Jinlin; Ni, Peihong

2017-04-26

Polyphosphoesters (PPEs), as potential candidates for biocompatible and biodegradable polymers, play an important role in material science. Various synthetic methods have been employed in the preparation of PPEs such as polycondensation, polyaddition, ring-opening polymerization, and olefin metathesis polymerization. In this study, a series of linear PPEs has been prepared via one-step Michael addition polymerization. Subsequently, camptothecin (CPT) derivatives containing disulfide bonds and azido groups were linked onto the side chain of the PPE through Cu(I)-catalyzed azidealkyne cyclo-addition "click" chemistry to yield a reduction-responsive polymeric prodrug P(EAEP-PPA)-g-ss-CPT. The chemical structures were characterized by nuclear magnetic resonance spectroscopy, gel permeation chromatography, Fourier transform infrared, ultraviolet-visible spectrophotometer, and high performance liquid chromatograph analyses, respectively. The amphiphilic prodrug could self-assemble into micelles in aqueous solution. The average particle size and morphology of the prodrug micelles were measured by dynamic light scattering and transmission electron microscopy, respectively. The results of size change under different conditions indicate that the micelles possess a favorable stability in physiological conditions and can be degraded in reductive medium. Moreover, the studies of in vitro drug release behavior confirm the reduction-responsive degradation of the prodrug micelles. A methyl thiazolyl tetrazolium assay verifies the good biocompatibility of P(EAEP-PPA) not only for normal cells, but also for tumor cells. The results of cytotoxicity and the intracellular uptake about prodrug micelles further demonstrate that the prodrug micelles can efficiently release CPT into 4T1 or HepG2 cells to inhibit the cell proliferation. All these results show that the polyphosphoester-based prodrug can be used for triggered drug delivery system in cancer treatment.

Asymmetric Michael Addition Mediated by Chiral Ionic Liquids.

PubMed

Suzuki, Yumiko

2018-06-01

Chiral ionic liquids with a focus on their applications in asymmetric Michael additions and related reactions were reviewed. The examples were classified on the basis of the mode of asymmetric induction (e.g., external induction/non-covalent interaction or internal induction/covalent bond formation), the roles in reactions (as a solvent or catalyst), and their structural features (e.g., imidazolium-based chiral cations, other chiral oniums; proline derivatives). Most of the reactions with high chiral induction are Michael addition of ketones or aldehydes to chalcones or nitrostyrenes where proline-derived chiral ionic liquids catalyze the reaction through enamine/ iminium formation. Many reports demonstrate the recyclability of ionic liquid-tagged pyrrolidines.

Mechanism of Action of Thalassospiramides, A New Class of Calpain Inhibitors

PubMed Central

Lu, Liang; Meehan, Michael J.; Gu, Shuo; Chen, Zhilong; Zhang, Weipeng; Zhang, Gen; Liu, Lingli; Huang, Xuhui; Dorrestein, Pieter C.; Xu, Ying; Moore, Bradley S.; Qian, Pei-Yuan

2015-01-01

Thalassospiramides comprise a large family of lipopeptide natural products produced by Thalassospira and Tistrella marine bacteria. Here we provide further evidence of their nanomolar inhibitory activity against the human calpain 1 protease. Analysis of structure-activity relationship data supported our hypothesis that the rigid 12-membered ring containing an α,β-unsaturated carbonyl moiety is the pharmacologically active functional group, in contrast to classic electrophilic “warheads” in known calpain inhibitors. Using a combination of chemical modifications, mass spectrometric techniques, site-directed mutagenesis, and molecular modeling, we show the covalent binding of thalassospiramide's α,β-unsaturated carbonyl moiety to the thiol group of calpain's catalytic Cys115 residue by a Michael 1,4-addition reaction. As nanomolar calpain inhibitors with promising selectivity and low toxicity from natural sources are rare, we consider thalassospiramides as promising drug leads. PMID:25740631

Mechanism of action of thalassospiramides, a new class of calpain inhibitors.

PubMed

Lu, Liang; Meehan, Michael J; Gu, Shuo; Chen, Zhilong; Zhang, Weipeng; Zhang, Gen; Liu, Lingli; Huang, Xuhui; Dorrestein, Pieter C; Xu, Ying; Moore, Bradley S; Qian, Pei-Yuan

2015-03-05

Thalassospiramides comprise a large family of lipopeptide natural products produced by Thalassospira and Tistrella marine bacteria. Here we provide further evidence of their nanomolar inhibitory activity against the human calpain 1 protease. Analysis of structure-activity relationship data supported our hypothesis that the rigid 12-membered ring containing an α,β-unsaturated carbonyl moiety is the pharmacologically active functional group, in contrast to classic electrophilic "warheads" in known calpain inhibitors. Using a combination of chemical modifications, mass spectrometric techniques, site-directed mutagenesis, and molecular modeling, we show the covalent binding of thalassospiramide's α,β-unsaturated carbonyl moiety to the thiol group of calpain's catalytic Cys115 residue by a Michael 1,4-addition reaction. As nanomolar calpain inhibitors with promising selectivity and low toxicity from natural sources are rare, we consider thalassospiramides as promising drug leads.

Negative ion electrospray ionization mass spectrometry of nucleoside phosphoramidate monoesters: elucidation of novel rearrangement mechanisms by multistage mass spectrometry incorporating in-source deuterium labelling.

PubMed

Xu, Peng-Xiang; Hu, An-Fu; Hu, Dan; Gao, Xiang; Zhao, Yu-Fen

2008-10-01

Several O-2',3'-isopropylideneuridine-O-5'-phosphoramidate monoesters were synthesized and analyzed by negative ion electrospray ionization tandem mass spectrometry (ESI-MS(n)). Two kinds of novel rearrangement reactions were observed due to the difference in the amino acid in the nucleoside phosphoramidate monoesters, and possible mechanisms were proposed. One involves a five-membered cyclic transition state. The other is formation of a stable five-membered ring intermediate by Michael addition. Results were confirmed by tandem mass spectrometry and isotopically labeled hydrogen atoms. Furthermore, the internal hydrogen exchange between active hydrogen and methyl acrylate in the heated capillary of the mass spectrometer was found. The characteristic fragmentation behavior in ESI-MS may be used to monitor this kind of compounds in the biological metabolism.

Catalyst-free and solvent-free Michael addition of 1,3-dicarbonyl compounds to nitroalkenes by a grinding method

PubMed Central

Xie, Zong-Bo; Wu, Ming-Yu; He, Ting; Le, Zhang-Gao

2012-01-01

Summary An environmentally benign, fast and convenient protocol has been developed for the Michael addition of 1,3-dicarbonyl compounds to β-nitroalkenes in good to excellent yields by a grinding method under catalyst- and solvent-free conditions. PMID:22563352

Synthesis of diazatricyclic core of Madangamines from cis-perhydroisoquinolines.

PubMed

Quirante, Josefina; Paloma, Laura; Diaba, Faïza; Vila, Xavier; Bonjoch, Josep

2008-01-18

Synthesis of the tricyclic core of madangamine alkaloids has been achieved in a 10-step sequence starting from a 4-(aminomethyl)anisole derivative. A Birch reduction and acylation with cyanoacetic acid followed by an intramolecular Michael process renders a polyfunctionalized cis-perhydroisoquinoline. A diastereoselective allylation and reduction of amide, nitrile, and ketone groups leads to a bicyclic alcohol, which undergoes aminocyclization through the nosyl derivative to the diazatricyclic ring.

Robust Electrical Transfer System (RETS) for Solar Array Drive Mechanism SlipRing Assembly

NASA Astrophysics Data System (ADS)

Bommottet, Daniel; Bossoney, Luc; Schnyder, Ralph; Howling, Alan; Hollenstein, Christoph

2013-09-01

Demands for robust and reliable power transmission systems for sliprings for SADM (Solar Array Drive Mechanism) are increasing steadily. As a consequence, it is required to know their performances regarding the voltage breakdown limit.An understanding of the overall shape of the breakdown voltage versus pressure curve is established, based on experimental measurements of DC (Direct Current) gas breakdown in complex geometries compared with a numerical simulation model.In addition a detailed study was made of the functional behaviour of an entire wing of satellite in a like- operational mode, comprising the solar cells, the power transmission lines, the SRA (SlipRing Assembly), the power S3R (Sequential Serial/shunt Switching Regulators) and the satellite load to simulate the electrical power consumption.A test bench able to measure automatically the: a)breakdown voltage versus pressure curve and b)the functional switching performances, was developed and validated.

Asymmetric Michael Addition Mediated by Chiral Ionic Liquids

PubMed Central

Suzuki, Yumiko

2018-01-01

Chiral ionic liquids with a focus on their applications in asymmetric Michael additions and related reactions were reviewed. The examples were classified on the basis of the mode of asymmetric induction (e.g., external induction/non-covalent interaction or internal induction/covalent bond formation), the roles in reactions (as a solvent or catalyst), and their structural features (e.g., imidazolium-based chiral cations, other chiral oniums; proline derivatives). Most of the reactions with high chiral induction are Michael addition of ketones or aldehydes to chalcones or nitrostyrenes where proline-derived chiral ionic liquids catalyze the reaction through enamine/ iminium formation. Many reports demonstrate the recyclability of ionic liquid-tagged pyrrolidines. PMID:29861702

HIGHLY DISATEREOSELECTIVE MICHAEL ADDITION OF FLAVANONE TO ITS CHALCONE PRECURSOR UNDER SOLVENT-FREE CONDITIONS USING MICROWAVES [POSTER

EPA Science Inventory

Substituted 2'-hydroxychalcones were found to give an equilibrium mixture of the starting chalcone and the corresponding flavanone inf 4.6-1:3 ratio in the presence of DBU gave two hitherto unknown diasteromeric dimers in a highly diastereoselective Michael addition of the carban...

Sequentially evaporated thin film YBa2Cu3O(7-x) superconducting microwave ring resonator

NASA Technical Reports Server (NTRS)

Rohrer, Norman J.; To, Hing Y.; Valco, George J.; Bhasin, Kul B.; Chorey, Chris; Warner, Joseph D.

1990-01-01

There is great interest in the application of thin film high temperature superconductors in high frequency electronic circuits. A ring resonator provides a good test vehicle for assessing the microwave losses in the superconductor and for comparing films made by different techniques. Ring resonators made of YBa2Cu3O(7-x) have been investigated on LaAlO3 substrates. The superconducting thin films were deposited by sequential electron beam evaporation of Cu, Y, and BaF2 with a post anneal. Patterning of the superconducting film was done using negative photolithography. A ring resonator was also fabricated from a thin gold film as a control. Both resonators had a gold ground plane on the backside of the substrate. The ring resonators' reflection coefficients were measured as a function of frequency from 33 to 37 GHz at temperatures ranging from 20 K to 68 K. The resonator exhibited two resonances which were at 34.5 and 35.7 GHz at 68 K. The resonant frequencies increased with decreasing temperature. The magnitude of the reflection coefficients was in the calculation of the unloaded Q-values. The performance of the evaporated and gold resonator are compared with the performance of a laser ablated YBa2Cu3O(7-x) resonator. The causes of the double resonance are discussed.

A facile and efficient method of enzyme immobilization on silica particles via Michael acceptor film coatings: immobilized catalase in a plug flow reactor.

PubMed

Bayramoglu, Gulay; Arica, M Yakup; Genc, Aysenur; Ozalp, V Cengiz; Ince, Ahmet; Bicak, Niyazi

2016-06-01

A novel method was developed for facile immobilization of enzymes on silica surfaces. Herein, we describe a single-step strategy for generating of reactive double bonds capable of Michael addition on the surfaces of silica particles. This method was based on reactive thin film generation on the surfaces by heating of impregnated self-curable polymer, alpha-morpholine substituted poly(vinyl methyl ketone) p(VMK). The generated double bonds were demonstrated to be an efficient way for rapid incorporation of enzymes via Michael addition. Catalase was used as model enzyme in order to test the effect of immobilization methodology by the reactive film surface through Michael addition reaction. Finally, a plug flow type immobilized enzyme reactor was employed to estimate decomposition rate of hydrogen peroxide. The highly stable enzyme reactor could operate continuously for 120 h at 30 °C with only a loss of about 36 % of its initial activity.

Production of Low-Freezing-Point Highly Branched Alkanes through Michael Addition.

PubMed

Jing, Yaxuan; Xia, Qineng; Liu, Xiaohui; Wang, Yanqin

2017-12-22

A new approach for the production of low-freezing-point, high-quality fuels from lignocellulose-derived molecules was developed with Michael addition as the key step. Among the investigated catalysts, CoCl 2 ⋅6 H 2 O was found most active for the Michael addition of 2,4-pentanedione with FA (single aldol adduct of furfural and acetone, 4-(2-furanyl)-3-butene-2-one). Over CoCl 2 ⋅6 H 2 O, a high carbon yield of C 13 oxygenates (about 75 %) can be achieved under mild conditions (353 K, 20 h). After hydrodeoxygenation, low-freezing-point (<223 K) branched alkanes with 13 carbons within jet fuel ranges were obtained over a Pd/NbOPO 4 catalyst. Furthermore, C 18,23 fuel precursors could be easily synthesized through Michael addition of 2,4-pentanedione with DFA (double-condensation product of furfural and acetone) under mild conditions and the molar ratio of C 18 /C 23 is dependent on the reaction conditions of Michael addition. After hydrodeoxygenation, high density (0.8415 g mL -1 ) and low-freezing-point (<223 K) branched alkanes with 18, 23 carbons within lubricant range were also obtained over a Pd/NbOPO 4 catalyst. These highly branched alkanes can be directly used as transportation fuels or additives. This work opens a new strategy for the synthesis of highly branched alkanes with low freezing point from renewable biomass. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

“Click, Click, Cyclize”: A DOS Approach to Sultams Utilizing Vinyl Sulfonamide Linchpins

PubMed Central

Zhou, Aihua; Rayabarapu, Dinesh; Hanson, Paul R.

2009-01-01

A diversity-oriented synthesis (DOS) strategy termed “Click, Click, Cyclize” is reported. This approach relies on functional group (FG) pairing between a vinyl sulfonamide and an array of functional groups to synthesize skeletally diverse sultams. Several FG pairing pathways on central tertiary vinyl sulfonamide linchpins have been developed including intramolecular Heck, aza-Michael, ring-closing enyne metathesis, Pauson—Khand, and chemoselective oxidation/Baylis—Hillman reactions. PMID:19115841

Poly(phenylene)-based anion exchange membrane

DOEpatents

Hibbs, Michael [Albuquerque, NM; Cornelius, Christopher J [Albuquerque, NM; Fujimoto, Cy H [Albuquerque, NM

2011-02-15

A poly(phenylene) compound of copolymers that can be prepared with either random or multiblock structures where a first polymer has a repeat unit with a structure of four sequentially connected phenyl rings with a total of 2 pendant phenyl groups and 4 pendant tolyl groups and the second polymer has a repeat unit with a structure of four sequentially connected phenyl rings with a total of 6 pendant phenyl groups. The second polymer has chemical groups attached to some of the pendant phenyl groups selected from CH.sub.3, CH.sub.2Br, and CH.sub.2N(CH.sub.3).sub.3Br groups. When at least one group is CH.sub.2N(CH.sub.3).sub.3Br, the material functions as an anion exchange membrane.

Synthesis of Aromatic Aza-metallapentalenes from Metallabenzene via Sequential Ring Contraction/Annulation

NASA Astrophysics Data System (ADS)

Wang, Tongdao; Han, Feifei; Huang, Haiping; Li, Jinhua; Zhang, Hong; Zhu, Jun; Lin, Zhenyang; Xia, Haiping

2015-04-01

The concept of aromaticity has long played an important role in chemistry and continues to fascinate both experimentalists and theoreticians. Among the archetypal aromatic compounds, heteroaromatics are particularly attractive. Recently, substitution of a transition-metal fragment for a carbon atom in the anti-aromatic hydrocarbon pentalene has led to the new heteroaromatic osmapentalenes. However, construction of the aza-homolog of osmapentalenes cannot be accomplished by a similar synthetic manipulation. Here, we report the synthesis of aza-osmapentalenes by sequential ring contraction/annulation reactions of osmabenzenes via osmapentafulvenes. Nuclear magnetic resonance spectra, X-ray crystallographic analysis, and DFT calculations all suggest that these aza-osmapentalenes exhibit aromatic character. Thus, the stepwise transformation of metallabenzenes to metallapentafulvenes and then aza-metallapentalenes provides an efficient and facile synthetic route to these bicyclic heteroaromatics.

Redox and Lewis acid relay catalysis: a titanocene/zinc catalytic platform in the development of multicomponent coupling reactions.

PubMed

Gianino, Joseph B; Campos, Catherine A; Lepore, Antonio J; Pinkerton, David M; Ashfeld, Brandon L

2014-12-19

A titanocene-catalyzed multicomponent coupling is described herein. Using catalytic titanocene, phosphine, and zinc dust, zinc acetylides can be generated from the corresponding iodoalkynes to affect sequential nucleophilic additions to aromatic aldehydes. The intermediate propargylic alkoxides are trapped in situ with acetic anhydride, which are susceptible to a second nucleophilic displacement upon treatment with a variety of electron-rich species, including acetylides, allyl silanes, electron-rich aromatics, silyl enol ethers, and silyl ketene acetals. Additionally, employing cyclopropane carboxaldehydes led to ring-opened products resulting from iodine incorporation. Taken together, these results form the basis for a new mode of three-component coupling reactions, which allows for rapid access to value added products in a single synthetic operation.

Efficient synthesis of optically active 4-nitro-cyclohexanones via bifunctional thiourea-base catalyzed double-Michael addition of nitromethane to dienones.

PubMed

Wu, Bin; Liu, Guo-Gui; Li, Mei-Qiu; Zhang, Yong; Zhang, Shao-Yun; Qiu, Jun-Ru; Xu, Xiao-Ping; Ji, Shun-Jun; Wang, Xing-Wang

2011-04-07

Thiourea-modified cinchona alkaloids as bifunctional catalysts and a base could catalyze a stepwise [5+1] cyclization of divinyl ketones with nitromethane via double Michael additions, furnishing optically active 4-nitro-cyclohexanones with good yields, excellent diastereoselectivities (>20 : 1) and high enantiomeric ratios (up to 97 : 3).

An efficient synthesis of the constrained peptidomimetic 2-oxo-3-(N-9-fluorenyloxycarbonylamino)-1-azabicyclo[4.3.0]nonane-9-carboxylic acid from pyroglutamic acid.

PubMed

Mandal, Pijus Kumar; Kaluarachchi, Kumar K; Ogrin, Douglas; Bott, Simon G; McMurray, John S

2005-11-25

[reaction: see text] Azabicyclo[X.Y.0]alkane amino acids are rigid dipeptide mimetics that are useful tools for structure-activity studies in peptide-based drug discovery. Herein, we report an efficient synthesis of three diastereomers of 9-tert-butoxycarbonyl-2-oxo-3-(N-tert-butoxycarbonylamino)-1-azabicyclo[4.3.0]nonane (3S,6S,9S, 3S,6R,9R, and 3S,6R,9S). Methyl N-Boc-pyroglutamate is cleaved with vinylmagnesium bromide to produce an acyclic gamma-vinyl ketone. Michael addition of N-diphenylmethyleneglycine tert-butyl ester produces the N-Boc-delta-oxo-alpha,omega-diaminoazelate intermediate, which, on hydrogenloysis, gives the fused ring system. Acidolytic deprotection followed by Fmoc-protection provided building blocks suitable for solid-phase synthesis.

Understanding the fate of the oxyallyl cation following Nazarov electrocyclization: sequential Wagner-Meerwein migrations and the synthesis of spirocyclic cyclopentenones

PubMed Central

Huang, Jie; Lebœuf, David; Frontier, Alison J.

2011-01-01

A general reaction sequence is described that involves Nazarov cyclization followed by two sequential Wagner Meerwein migrations, to afford spirocyclic compounds from divinyl ketones in the presence of one equivalent of copper(II) complexes. A detailed investigation of this sequence is described including a study of substrate scope and limitations. It was found that after 4π electrocyclization, two different pathways are available to the oxyallyl cation intermediate: elimination of a proton can give the usual Nazarov cycloadduct, or ring contraction can give an alternative tertiary carbocation. After ring contraction, either [1,2]-hydride or carbon migration can occur, depending upon the substitution pattern of the substrate, to furnish spirocyclic products. The rearrangement pathway is favored over the elimination pathway when catalyst loading was high and the copper(II) counterion is noncoordinating. Several ligands were found to be effective for the reaction. Thus, the reaction sequence can be controlled by judicious choice of reaction conditions to allow selective generation of richly functionalized spirocycles. The three steps of the sequence are stereospecific: electrocyclization followed by two [1,2]-suprafacial Wagner-Meerwein shifts: the ring contraction and then an hydride, alkenyl or aryl shift. The method allows stereospecific installation of adjacent stereocenters or adjacent quaternary centers arrayed around a cyclopentenone ring. PMID:21466152

Asymmetric synthesis of α-amino acids via homologation of Ni(II) complexes of glycine Schiff bases. Part 3: Michael addition reactions and miscellaneous transformations.

PubMed

Aceña, José Luis; Sorochinsky, Alexander E; Soloshonok, Vadim

2014-09-01

The major goal of this review is a critical discussion of the literature data on asymmetric synthesis of α-amino acids via Michael addition reactions involving Ni(II)-complexes of amino acids. The material covered is divided into two conceptually different groups dealing with applications of: (a) Ni(II)-complexes of glycine as C-nucleophiles and (b) Ni(II)-complexes of dehydroalanine as Michael acceptors. The first group is significantly larger and consequently subdivided into four chapters based on the source of stereocontrolling element. Thus, a chiral auxiliary can be used as a part of nucleophilic glycine Ni(II) complex, Michael acceptor or both, leading to the conditions of matching vs. mismatching stereochemical preferences. The particular focus of the review is made on the practical aspects of the methodology under discussion and mechanistic considerations.

Automated Synthesis of a 184-Member Library of Thiadiazepan-1, 1-dioxide-4-ones

PubMed Central

Fenster, Erik; Long, Toby R.; Zang, Qin; Hill, David; Neuenswander, Benjamin; Lushington, Gerald H.; Zhou, Aihua; Santini, Conrad; Hanson, Paul R.

2011-01-01

The construction of a 225-member (3 × 5 × 15) library of thiadiazepan-1,1-dioxide-4-ones was performed on a Chemspeed Accelerator (SLT-100) automated parallel synthesis platform, culminating in the successful preparation of 184/225 sultams. Three sultam core scaffolds were prepared based upon the utilization of an aza-Michael reaction on a multifunctional vinyl sulfonamide linchpin. The library exploits peripheral diversity in the form of a sequential, two-step [3 + 2] Huisgen cycloaddition/Pd-catalyzed Suzuki–Miyaura coupling sequence. PMID:21309582

Automated synthesis of a 184-member library of thiadiazepan-1,1-dioxide-4-ones.

PubMed

Fenster, Erik; Long, Toby R; Zang, Qin; Hill, David; Neuenswander, Benjamin; Lushington, Gerald H; Zhou, Aihua; Santini, Conrad; Hanson, Paul R

2011-05-09

The construction of a 225-member (3 × 5 × 15) library of thiadiazepan-1,1-dioxide-4-ones was performed on a Chemspeed Accelerator (SLT-100) automated parallel synthesis platform, culminating in the successful preparation of 184/225 sultams. Three sultam core scaffolds were prepared based upon the utilization of an aza-Michael reaction on a multifunctional vinyl sulfonamide linchpin. The library exploits peripheral diversity in the form of a sequential, two-step [3 + 2] Huisgen cycloaddition/Pd-catalyzed Suzuki-Miyaura coupling sequence.

Theoretical study on the reaction mechanisms of Michael chirality addition between propionaldehyde and nitroalkene catalyzed by an enantioselective catalyst.

PubMed

Zhou, Xinming; Li, Ling; Sun, Xuejun; Wang, Yajun; Du, Dongmei; Fu, Hui

2018-06-01

The asymmetric Michael addition between propionaldehyde and nitroalkene catalyzed by 8-(ethoxycarbonyl)-1,2,3,3a,8,8a-hexahydropyrrolo[2,3-b]indole-2-carboxylic acid has obtained relatively high yields and excellent enantioselectivities at room temperature. In this study, the molecular structures and optical activity of the most stable conformation I are optimized at B3LYP/6-311++ G(d,p) level. We find that levorotatory conformation I catalyzing the same Michael addition can produce laevo-product A and dextrorotatory conformation I' can obtain the dextral-product A'. These results have guiding significance for further studying on the new chemzymes and the mechanism of the obtained different chiral products. © 2018 Wiley Periodicals, Inc.

Quantum coherent π-electron rotations in a non-planar chiral molecule induced by using a linearly polarized UV laser pulse

NASA Astrophysics Data System (ADS)

Mineo, Hirobumi; Fujimura, Yuichi

2015-06-01

We propose an ultrafast quantum switching method of π-electron rotations, which are switched among four rotational patterns in a nonplanar chiral aromatic molecule (P)-2,2’- biphenol and perform the sequential switching among four rotational patterns which are performed by the overlapped pump-dump laser pulses. Coherent π-electron dynamics are generated by applying the linearly polarized UV pulse laser to create a pair of coherent quasidegenerated excited states. We also plot the time-dependent π-electron ring current, and discussed ring current transfer between two aromatic rings.

STS-45 Atlantis, Orbiter Vehicle (OV) 104, crew insignia

NASA Image and Video Library

1999-09-10

STS045-S-001 (October 1991) --- Designed by the crew members, the patch depicts the space shuttle launching from the Kennedy Space Center (KSC) into a high inclination orbit. From this vantage point, the Atmospheric Laboratory for Applications and Science (ATLAS) payload can view Earth, the sun, and their dynamic interactions against the background of space. Earth is prominently displayed and is the focus of the mission's space plasma physics and Earth sciences observations. The colors of the setting sun, measured by sensitive instruments, provide detailed information about ozone, carbon dioxide and other gases which determine Earth's climate and environment. Encircling the scene are the names of the flight crew members: Charles F. Bolden Jr., commander; Brian Duffy, pilot; C. Michael Foale, David C. Leestma, and Kathryn D. Sullivan, all mission specialists; Dirk Frimout and Byron K. Lichtenberg, payload specialists. The additional star in the ring is to recognize Charles R. Chappell and Michael Lampton, alternate payload specialists, and the entire ATLAS-1 team for its dedication and support of this "Mission to Planet Earth" (MTPE). The NASA insignia design for space shuttle flights is reserved for use by the astronauts and for other official use as the NASA Administrator may authorize. Public availability has been approved only in the form of illustrations by the various news media. When and if there is any change in this policy, which is not anticipated, it will be publicly announced. Photo credit: NASA

Direct Enantioselective Conjugate Addition of Carboxylic Acids with Chiral Lithium Amides as Traceless Auxiliaries

PubMed Central

2016-01-01

Michael addition is a premier synthetic method for carbon–carbon and carbon–heteroatom bond formation. Using chiral dilithium amides as traceless auxiliaries, we report the direct enantioselective Michael addition of carboxylic acids. A free carboxyl group in the product provides versatility for further functionalization, and the chiral reagent can be readily recovered by extraction with aqueous acid. The method has been applied in the enantioselective total synthesis of the purported structure of pulveraven B. PMID:25562717

Direct enantioselective conjugate addition of carboxylic acids with chiral lithium amides as traceless auxiliaries.

PubMed

Lu, Ping; Jackson, Jeffrey J; Eickhoff, John A; Zakarian, Armen

2015-01-21

Michael addition is a premier synthetic method for carbon-carbon and carbon-heteroatom bond formation. Using chiral dilithium amides as traceless auxiliaries, we report the direct enantioselective Michael addition of carboxylic acids. A free carboxyl group in the product provides versatility for further functionalization, and the chiral reagent can be readily recovered by extraction with aqueous acid. The method has been applied in the enantioselective total synthesis of the purported structure of pulveraven B.

STS-45 MS Foale dons EMU with technicians' help in JSC's WETF Bldg 29

NASA Technical Reports Server (NTRS)

1991-01-01

STS-45 Atlantis, Orbiter Vehicle (OV) 104, Mission Specialist (MS) C. Michael Foale stands on a platform as technicians help him don his extravehicular mobility unit (EMU). The technicians are preparing to connect the EMU upper and lower torsos at the waist ring. When fully suited, Foale will be lowered into a nearby 25 ft deep pool for an underwater simulation of contingency extravehicular activity (EVA) procedures. The pool is located in JSC's Weightless Environment Training Facility (WETF) Bldg 29.

N719 dye-sensitized organophotocatalysis: enantioselective tandem Michael addition/oxyamination of aldehydes.

PubMed

Yoon, Hyo-Sang; Ho, Xuan-Huong; Jang, Jiyeon; Lee, Hwa-Jung; Kim, Seung-Joo; Jang, Hye-Young

2012-07-06

A remarkably efficient photosensitizer, N719 dye, was used in asymmetric tandem Michael addition/oxyamination of aldehydes, rendering α,β-substituted aldehydes in good yields with excellent levels of enantioselectivity and diastereoselectivity. This is the first report of a multiorganocatalytic reaction involving iminium catalysis and photoinduced singly occupied molecular orbital (SOMO) catalysis. This reaction is expected to expand the scope of tandem organocatalytic reactions.

Chiral-catalyst-based convergent synthesis of HIV protease inhibitor GRL-06579A.

PubMed

Mihara, Hisashi; Sohtome, Yoshihiro; Matsunaga, Shigeki; Shibasaki, Masakatsu

2008-02-01

Catalytic asymmetric synthesis of GRL-06579A (1), an HIV-1 protease inhibitor effective against multi-protease-inhibitor-resistant viruses, is described. A convergent strategy that utilizes heterobimetallic multifunctional catalysts developed in our group is a key feature of the synthesis. The chirality of the bicyclic tetrahydrofuran unit of 1 was introduced through Al-Li-bis(binaphthoxide) (ALB) catalyst-controlled Michael addition of dimethyl malonate to racemic 4-O-protected cyclopentenone. ALB afforded not only the trans adduct with up to 96% ee from a matched substrate through kinetic resolution, but also the cis adduct with 99% ee through a catalyst-controlled Michael addition to a mismatched substrate. The Michael addition to produce the unusual cis adduct is described in detail. The framework of the bicyclic tetrahydrofuran was constructed by an intramolecular oxy-Michael reaction. The amino alcohol unit was constructed by an La-Li3-tris(binaphthoxide) (LLB)-catalyzed diastereoselective nitroaldol reaction of N-Boc aldehyde (Boc = tert-butoxycarbonyl) derived from L-phenylalanine. LLB promoted the nitroaldol reaction without racemization of the chiral aldehyde to give the nitroaldol adduct in 85% yield and with 93:7 diastereoselectivity and over 99% ee.

Basic-functionalized recyclable ionic liquid catalyst: A solvent-free approach for Michael addition of 1,3-dicarbonyl compounds to nitroalkenes under ultrasound irradiation.

PubMed

Narayanaperumal, Senthil; da Silva, Rodrigo César; Feu, Karla Santos; de la Torre, Alexander Fernández; Corrêa, Arlene G; Paixão, Márcio Weber

2013-05-01

A task-specific ionic liquid (TSIL) has been introduced as a recyclable catalyst in Michael addition. A series of nitroalkenes and various C-based nucleophiles were reacted in the presence of 30mol% of recyclable basic-functionalized ionic liquid. Good to excellent yields were obtained in 30min under ultrasound irradiation. Copyright © 2012 Elsevier B.V. All rights reserved.

Superelastic and pH-Responsive Degradable Dendrimer Cryogels Prepared by Cryo-aza-Michael Addition Reaction.

PubMed

Wang, Juan; Yang, Hu

2018-05-08

Dendrimers exhibit super atomistic features by virtue of their well-defined discrete quantized nanoscale structures. Here, we show that hyperbranched amine-terminated polyamidoamine (PAMAM) dendrimer G4.0 reacts with linear polyethylene glycol (PEG) diacrylate (575 g/mol) via the aza-Michael addition reaction at a subzero temperature (-20 °C), namely cryo-aza-Michael addition, to form a macroporous superelastic network, i.e., dendrimer cryogel. Dendrimer cryogels exhibit biologically relevant Young's modulus, high compression elasticity and super resilience at ambient temperature. Furthermore, the dendrimer cryogels exhibit excellent rebound performance and do not show significant stress relaxation under cyclic deformation over a wide temperature range (-80 to 100 °C). The obtained dendrimer cryogels are stable at acidic pH but degrade quickly at physiological pH through self-triggered degradation. Taken together, dendrimer cryogels represent a new class of scaffolds with properties suitable for biomedical applications.

Synthesis of pyroglutamic acid derivatives via double michael reactions of alkynones.

PubMed

Scansetti, Myriam; Hu, Xiangping; McDermott, Benjamin P; Lam, Hon Wai

2007-05-24

In the presence of substoichiometric quantities of potassium tert-butoxide and an additional metal salt, amide-tethered diacids undergo double Michael reactions with alkynones to provide highly functionalized pyroglutamic acid derivatives. The metal salt was found to play an important role in improving the diastereoselectivities of the reactions.

The chemical foundations of nitroalkene fatty acid signaling through addition reactions with thiols.

PubMed

Turell, Lucía; Steglich, Martina; Alvarez, Beatriz

2018-03-22

Nitroalkene fatty acids can be formed in vivo and administered exogenously. They exert pleiotropic signaling actions with cytoprotective and antiinflammatory effects. The presence of the potent electron withdrawing nitro group confers electrophilicity to the adjacent β-carbon. Thiols (precisely, thiolates) are strong nucleophiles and can react with nitroalkene fatty acids through reversible Michael addition reactions. In addition, nitroalkene fatty acids can undergo several other processes including metabolic oxidation, reduction, esterification, nitric oxide release and partition into hydrophobic compartments. The signaling actions of nitroalkenes are mainly mediated by reactions with critical thiols in regulatory proteins. Thus, the thio-Michael addition reaction provides a framework for understanding the molecular basis of the biological effects of nitroalkene fatty acids at the crossroads of thiol signaling and electrophilic lipid signaling. In this review, we describe the reactions of nitroalkene fatty acids in biological contexts. We focus on the Michael addition-elimination reaction with thiols and its mechanism, and extrapolate kinetic and thermodynamic considerations to in vivo settings. Copyright © 2018 Elsevier Inc. All rights reserved.

Diversity oriented synthesis of tricyclic compounds from glycals using the Ferrier and the Pauson-Khand reactions.

PubMed

Hotha, Srinivas; Tripathi, Ashish

2005-01-01

Diversity oriented synthesis of tricyclic compounds was achieved using a combination of the Ferrier reaction and the Pauson-Khand reaction. Ferrier reaction was effected using NbCl5, and the Pauson-Khand reaction was carried out using Co2(CO)8, acetonitrile-dimethoxyethane. Michael additions using various alkyl, aryl, and heterocyclic thiols were also performed successfully. The Ferrier, Pauson-Khand, and Michael addition reactions were found to be highly diastereoselective.

Pyrrolidinyl-camphor derivatives as a new class of organocatalyst for direct asymmetric Michael addition of aldehydes and ketones to beta-nitroalkenes.

PubMed

Ting, Ying-Fang; Chang, Chihliang; Reddy, Raju Jannapu; Magar, Dhananjay R; Chen, Kwunmin

2010-06-18

Practical and convenient synthetic routes have been developed for the synthesis of a new class of pyrrolidinyl-camphor derivatives (7 a-h). These novel compounds were screened as catalysts for the direct Michael addition of symmetrical alpha,alpha-disubstituted aldehydes to beta-nitroalkenes. When this asymmetric transformation was catalyzed by organocatalyst 7 f, the desired Michael adducts were obtained in high chemical yields, with high to excellent stereoselectivities (up to 98:2 diastereomeric ratio (d.r.) and 99 % enantiomeric excess (ee)). The scope of the catalytic system was expanded to encompass various aldehydes and ketones as the donor sources. The synthetic application was demonstrated by the synthesis of a tetrasubstituted-cyclohexane derivative from (S)-citronellal, with high stereoselectivity.

Hemocompatibility improvement of poly(ethylene terephthalate) via self-polymerization of dopamine and covalent graft of zwitterions.

PubMed

Cai, Xianmei; Yuan, Jiang; Chen, Shuangchun; Li, Pengfei; Li, Li; Shen, Jian

2014-03-01

Poly (ethylene terephthalate) (PET) has been widely adopted as a scaffold biomaterial, but further hemocompatibility improvement is still needed for wide biomedical applications. Inspired by the composition of adhesive proteins in mussels, we propose to use self-polymerized dopamine to form a surface-adherent polydopamine layer onto PET sheet, followed by Michael addition with N,N-dimethylethylenediamine (DMDA) to build tertiary amine, and final zwitterions(sulfobetaine and carboxybetaine) construction through ring-opening reaction. Physicochemical properties of substrates were demonstrated by water contact angle measurement, attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS). The hemocompatibility was evaluated by platelet adhesion, hemolytic, and protein adsorption. The results showed that the zwitterions immobilized PET endowed with improved resistance to nonspecific protein adsorption and platelet adhesion as well as nonhemolytic. The zwitterions with desirable hemocompatibility can be readily tailored to catheter for various biomedical applications. Copyright © 2013 Elsevier B.V. All rights reserved.

Aza-Michael Reaction for an Undergraduate Organic Chemistry Laboratory

ERIC Educational Resources Information Center

Nigam, Manisha; Rush, Brittney; Patel, Jay; Castillo, Raul; Dhar, Preeti

2016-01-01

A green, aza-Michael reaction is described that can be used to teach undergraduate students conjugate addition of nitrogen nucleophile to an a,ß-unsaturated ester. Students analyze spectral data of the product obtained from the assigned reaction to determine product structure and propose the mechanism of its formation. The experiment requires…

Sequential effects of severe drought and defoliation on tree growth and survival in a diverse temperate mesic forest

NASA Astrophysics Data System (ADS)

Matthes, J. H.; Pederson, N.; David, O.; Martin-Benito, D.

2017-12-01

Understanding the effects of climate change and biotic disturbance within diverse temperate mesic forests is complicated by the need to scale between impacts within individuals and across species in the community. It is not clear how these impacts within individuals and across a community influences the stand- and regional-scale response. Furthermore, co-occurring or sequential disturbances can make it challenging to interpret forest responses from observational data. In the northeastern United States, the 1960s drought was perhaps the most severe period of climatic stress within the past 300 years and negatively impacted the growth of individual trees across all species, but unevenly. Additionally, in 1981 the northeast experienced an outbreak of the defoliator Lymantria dispar, which preferentially consumes oak leaves, but in 1981 impacted a high proportion of other species as well. To investigate the effects of drought (across functional groups) and defoliation (within a functional group), we combined a long-term tree-ring dataset from an old-growth forest within the Palmaghatt Ravine in New York with a version of the Ecosystem Demography model that includes a scheme for representing forest insects and pathogens. We explored the sequential impacts of severe drought and defoliation on tree growth, community composition, and ecosystem-atmosphere interactions (carbon, water, and heat flux). W­e also conducted a set of modeling experiments with climate and defoliation disturbance scenarios to bound the potential long-term response of this forest to co-occurring and sequential drought-defoliator disturbances over the next fifty years.

Chiral N,N'-Dioxide-Organocatalyzed Regio-, Diastereo- and Enantioselective Michael Addition-Alkylation Reaction.

PubMed

Feng, Juhua; Yuan, Xiao; Luo, Weiwei; Lin, Lili; Liu, Xiaohua; Feng, Xiaoming

2016-10-24

A highly regio-, diastereo- and enantioselective Michael addition-alkylation reaction between α-substituted cyano ketones and (Z)-bromonitrostyrenes has been realized by using a chiral N,N'-dioxide as organocatalyst. A variety of substrates performed well in this reaction, and the corresponding multifunctionalized chiral 2,3-dihydrofurans were obtained in up to 95 % yield with 95:5 dr and 93 % ee. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Quantum chemical molecular dynamics simulation of single-walled carbon nanotube cap nucleation on an iron particle.

PubMed

Ohta, Yasuhito; Okamoto, Yoshiko; Page, Alister J; Irle, Stephan; Morokuma, Keiji

2009-11-24

The atomic scale details of single-walled carbon nanotube (SWNT) nucleation on metal catalyst particles are elusive to experimental observations. Computer simulation of metal-catalyzed SWNT nucleation is a challenging topic but potentially of great importance to understand the factors affecting SWNT diameters, chirality, and growth efficiency. In this work, we use nonequilibrium density functional tight-binding molecular dynamics simulations and report nucleation of sp(2)-carbon cap structures on an iron particle consisting of 38 atoms. One C(2) molecule was placed every 1.0 ps around an Fe(38) cluster for 30 ps, after which a further 410 ps of annealing simulation without carbon supply was performed. We find that sp(2)-carbon network nucleation and annealing processes occur in three sequential and repetitive stages: (A) polyyne chains on the metal surface react with each other to evolve into a Y-shaped polyyne junction, which preferentially form a five-membered ring as a nucleus; (B) polyyne chains on the first five-membered ring form an additional fused five- or six-membered ring; and (C) pentagon-to-hexagon self-healing rearrangement takes place with the help of short-lived polyyne chains, stabilized by the mobile metal atoms. The observed nucleation process resembles the formation of a fullerene cage. However, the metal particle plays a key role in differentiating the nucleation process from fullerene cage formation, most importantly by keeping the growing cap structure from closing into a fullerene cage and by keeping the carbon edge "alive" for the addition of new carbon material.

Facile and Promising Method for Michael Addition of Indole and Pyrrole to Electron-Deficient trans-β-Nitroolefins Catalyzed by a Hydrogen Bond Donor Catalyst Feist's Acid and Preliminary Study of Antimicrobial Activity

PubMed Central

Al Majid, Abdullah M. A.; Islam, Mohammad Shahidul; Barakat, Assem; Al-Agamy, Mohamed H. M.; Naushad, Mu.

2014-01-01

The importance of cooperative hydrogen-bonding effects has been demonstrated using novel 3-methylenecyclopropane-1,2-dicarboxylic acid (Feist's acid (FA)) as hydrogen bond donor catalysts for the addition of indole and pyrrole to trans-β-nitrostyrene derivatives. Because of the hydrogen bond donor (HBD) ability, Feist's acid (FA) has been introduced as a new class of hydrogen bond donor catalysts for the activation of nitroolefin towards nucleophilic substitution reaction. It has effectively catalyzed the Michael addition of indoles and pyrrole to β-nitroolefins under optimum reaction condition to furnish the corresponding Michael adducts in good to excellent yields (up to 98%). The method is general, atom-economical, convenient, and eco-friendly and could provide excellent yields and regioselectivities. Some newly synthesized compounds were for examined in vitro antimicrobial activity and their preliminary results are reported. PMID:24574906

Synthetic nat- or ent-steroids in as few as five chemical steps from epichlorohydrin

NASA Astrophysics Data System (ADS)

Kim, Wan Shin; Du, Kang; Eastman, Alan; Hughes, Russell P.; Micalizio, Glenn C.

2018-01-01

Today, more than 100 Food and Drug Administration-approved steroidal agents are prescribed daily for indications including heart failure, inflammation, pain and cancer. While triumphs in organic chemistry have enabled the establishment and sustained growth of the steroid pharmaceutical industry, the production of highly functionalized synthetic steroids of varying substitution and stereochemistry remains challenging, despite the numerous reports of elegant strategies for their de novo synthesis. Here, we describe an advance in chemical synthesis that has established an enantiospecific means to access novel steroids with unprecedented facility and flexibility through the sequential use of two powerful ring-forming reactions: a modern metallacycle-mediated annulative cross-coupling and a new acid-catalysed vinylcyclopropane rearrangement cascade. In addition to accessing synthetic steroids of either enantiomeric series, these steroidal products have been selectively functionalized within each of the four carbocyclic rings, a synthetic ent-steroid has been prepared on a multigram scale, the enantiomer of a selective oestrogen has been synthesized, and a novel ent-steroid with growth inhibitory properties in three cancer cell lines has been discovered.

An improved procedure to prepare 3-methyl-4-nitroalkylenethylisoxazoles and their reaction under catalytic enantioselective Michael addition with nitromethane.

PubMed

Moccia, Maria; Wells, Robert J; Adamo, Mauro F A

2015-02-21

Herein, we describe a short synthesis of 3-methyl-4-nitro-5-alkylethenyl isoxazoles and their reactivity as Michael acceptors. The title compounds reacted with nitromethane under phase-transfer catalysis to provide highly enantioenriched adducts (up to 93% ee) which were then converted to the corresponding γ-nitroacids.

Facile Iodine-Catalyzed Michael Addition of Indoles to α,α′-Bis(arylmethylene)cyclopentanones: An Efficient Synthesis of E-2-(3-Indolylphenylmethyl)-5-phenylmethylenecyclopentanones

PubMed Central

Pal, Rammohan; Das Gupta, Arpita; Mallik, Asok K.

2012-01-01

Iodine-catalyzed reaction of indoles with α,α′-bis(arylmethylene)cyclopentanones afforded one diastereomer of the corresponding Michael adducts, namely, E-2-(3-indolylphenylmethyl)-5-phenylmethylenecyclopentanones, in a good yield. The products form a new group of indole derivatives. PMID:24052849

Heterobimetallic Pd-Sn catalysis: a Suzuki, tandem ring-closing sequence toward indeno[2,1-b]thiophenes and indeno[2,1-b]indoles.

PubMed

Das, Debjit; Pratihar, Sanjay; Roy, Sujit

2012-09-21

Indeno[2,1-b]thiophene and indeno[1,2-b]indole motifs have been obtained in moderate to good yields from easily available substituted boronic acids, 2-bromo aryl/vinyl aldehydes, and nucleophiles such as arenes/heteroarenes and others using a catalytic combination of bimetallic "Pd-Sn" and AgPF(6). This formal three-component coupling involves a Suzuki reaction followed by nucleophile assisted tandem ring closure. The sequential synthesis of substituted heterocycle-fused indenes, benzofluorene, and fluorenes was also accomplished.

Rhodium-catalyzed sequential allylic amination and olefin hydroacylation reactions: enantioselective synthesis of seven-membered nitrogen heterocycles.

PubMed

Arnold, Jeffrey S; Mwenda, Edward T; Nguyen, Hien M

2014-04-01

Dynamic kinetic asymmetric amination of branched allylic acetimidates has been applied to the synthesis of 2-alkyl-dihydrobenzoazepin-5-ones. These seven-membered-ring aza ketones are prepared in good yield with high enantiomeric excess by rhodium-catalyzed allylic substitution with 2-amino aryl aldehydes followed by intramolecular olefin hydroacylation of the resulting alkenals. This two-step procedure is amenable to varied functionality and proves useful for the enantioselective preparation of these ring systems. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Substituted 1H-1,2,3-Triazol-4-yl-1H-pyrrolo[2,3-b]pyridines by De Novo One-Pot Ring Forming Coupling-Cyclization-Desilylation-CuAAC-Sequence.

PubMed

Müller, Thomas J J; Lessing, Timo; van Mark, Hauke

2018-05-04

Substituted 1H-1,2,3-triazol-4-yl-pyrrolo[2,3-b]pyridines are efficiently prepared by a one-pot coupling-cyclization-desilylation-CuAAC-sequence in the sense of a consecutive three-component fashion. The key feature of this novel de novo formation of azole and triazole anellation is the sequentially Pd/Cu-catalyzed process employing tri(iso-propyl)silylbutadiyne (TIPS-butadiyne) as a four-carbon building block. In addition, the sequence can be expanded in a four-component fashion also employing the in situ formation of the require azides. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The Electromechanical Behavior of a Micro-Ring Driven by Traveling Electrostatic Force

PubMed Central

Ye, Xiuqian; Chen, Yibao; Chen, Da-Chih; Huang, Kuo-Yi; Hu, Yuh-Chung

2012-01-01

There is no literature mentioning the electromechanical behavior of micro structures driven by traveling electrostatic forces. This article is thus the first to present the dynamics and stabilities of a micro-ring subjected to a traveling electrostatic force. The traveling electrostatic force may be induced by sequentially actuated electrodes which are arranged around the flexible micro-ring. The analysis is based on a linearized distributed model considering the electromechanical coupling effects between electrostatic force and structure. The micro-ring will resonate when the traveling speeds of the electrostatic force approach some critical speeds. The critical speeds are equal to the ratio of the natural frequencies to the wave number of the correlative natural mode of the ring. Apart from resonance, the ring may be unstable at some unstable traveling speeds. The unstable regions appear not only near the critical speeds, but also near some fractions of some critical speeds differences. Furthermore the unstable regions expand with increasing driving voltage. This article may lead to a new research branch on electrostatic-driven micro devices. PMID:22438705

Heterobimetallic Pd-Sn catalysis: Michael addition reaction with C-, N-, O-, and S-nucleophiles and in situ diagnostics.

PubMed

Das, Debjit; Pratihar, Sanjay; Roy, Sujit

2013-03-15

An efficient Michael addition reaction of differently substituted enones with carbon, sulfur, oxygen, and nitrogen nucleophiles has been achieved by a new heterobimetallic "Pd-Sn" catalyst system. The nature of the catalytically relevant species and their interactions with the enone moiety has been examined by spectroscopy. The effect of ligand and the coordination mode of enone with "Pd-Sn" heterobimetallic system have been investigated by kinetics and DFT studies. A straightforward application of this methodology is shown in the synthesis of 1,4-oxathiepane core.

Total synthesis of (±)-antroquinonol d.

PubMed

Sulake, Rohidas S; Jiang, Yan-Feng; Lin, Hsiao-Han; Chen, Chinpiao

2014-11-21

Total synthesis of (±)-antroquinonol D, which is isolated from very expensive and rarely found Antrodia camphorata and which has potential anticancer properties, was achieved from 4-methoxyphenol. In addition, a Michael addition to dimethoxy cyclohexadienones was studied. The main step involved chelation and substrate-controlled diastereoselective reduction of cyclohexenone and lactonization. Lactone synthesis facilitated the diastereoselective reduction of ketone, which help control the desired stereochemistry at the crucial stereogenic center in the natural product. Other key reactions in the synthesis involved a Michael addition of dimethyl malonate on cyclohexadienone, dihydroxylation, and Wittig olefination. A sesquiterpene side chain was synthesized through coupling with geranyl phenyl sulfide and Bouveault-Blanc reduction.

An Integral Part of the Frederick Community—Michael Dean | Poster

Cancer.gov

For more than 30 years, Michael Dean, Ph.D., has been an integral part of the NCI at Frederick community. In addition to studying several different aspects of genomics and cancer research, he has worked with the Werner H. Kirsten Student Intern Program and also volunteered his time with Mission of Mercy, a community-based organization providing free healthcare and free

Mechanism of Polyubiquitination by Human Anaphase-Promoting Complex: RING Repurposing for Ubiquitin Chain Assembly

DOE PAGES

Brown, Nicholas G.; Watson, Edmond R.; Weissmann, Florian; ...

2014-10-09

Polyubiquitination by E2 and E3 enzymes is a predominant mechanism regulating protein function. Some RING E3s, including anaphase-promoting complex/cyclosome (APC), catalyze polyubiquitination by sequential reactions with two different E2s. An initiating E2 ligates ubiquitin to an E3-bound substrate. Another E2 grows a polyubiquitin chain on the ubiquitin-primed substrate through poorly defined mechanisms. Here in this paper we show that human APC’s RING domain is repurposed for dual functions in polyubiquitination. The canonical RING surface activates an initiating E2-ubiquitin intermediate for substrate modification. However, APC engages and activates its specialized ubiquitin chain-elongating E2 UBE2S in ways that differ from current paradigms.more » During chain assembly, a distinct APC11 RING surface helps deliver a substrate-linked ubiquitin to accept another ubiquitin from UBE2S. Our data define mechanisms of APC/UBE2S-mediated polyubiquitination, reveal diverse functions of RING E3s and E2s, and provide a framework for understanding distinctive RING E3 features specifying ubiquitin chain elongation.« less

Thirty Points About Motivation From Skinner's Book Verbal Behavior

PubMed Central

Sundberg, Mark L.

2013-01-01

Skinner discussed the topic of motivation in every chapter of the book Verbal Behavior (1957), usually with his preferred terminology of “deprivation, satiation, and aversive stimulation.” In the current paper, direct quotations are used to systematically take the reader through 30 separate points made by Skinner in Verbal Behavior that collectively provide a comprehensive analysis of his position regarding the role of motivation in behavior analysis. In addition, various refinements and extensions of Skinner's analysis by Jack Michael and colleagues (Laraway, Snycerski, Michael, & Poling, 2003; Michael, 1982, 1988, 1993, 2000, 2004, 2007) are incorporated, along with suggestions for research and applications for several of the points. PMID:23814363

Synthesis, chemical reactivity as Michael acceptors, and biological potency of monocyclic cyanoenones, novel and highly potent anti-inflammatory and cytoprotective agents.

PubMed

Zheng, Suqing; Santosh Laxmi, Y R; David, Emilie; Dinkova-Kostova, Albena T; Shiavoni, Katherine H; Ren, Yanqing; Zheng, Ying; Trevino, Isaac; Bumeister, Ronald; Ojima, Iwao; Wigley, W Christian; Bliska, James B; Mierke, Dale F; Honda, Tadashi

2012-05-24

Novel monocyclic cyanoenones examined to date display unique features regarding chemical reactivity as Michael acceptors and biological potency. Remarkably, in some biological assays, the simple structure is more potent than pentacyclic triterpenoids (e.g., CDDO and bardoxolone methyl) and tricycles (e.g., TBE-31). Among monocyclic cyanoenones, 1 is a highly reactive Michael acceptor with thiol nucleophiles. Furthermore, an important feature of 1 is that its Michael addition is reversible. For the inhibition of NO production, 1 shows the highest potency. Notably, its potency is about three times higher than CDDO, whose methyl ester (bardoxolone methyl) is presently in phase III clinical trials. For the induction of NQO1, 1 also demonstrated the highest potency. These results suggest that the reactivity of these Michael acceptors is closely related to their biological potency. Interestingly, in LPS-stimulated macrophages, 1 causes apoptosis and inhibits secretion of TNF-α and IL-1β with potencies that are higher than those of bardoxolone methyl and TBE-31.

Michael Novak's "Business as a Calling" as a Vehicle for Addressing Ethical and Policy Concerns in a Business Law Course

ERIC Educational Resources Information Center

Murphy, Tonia Hap

2008-01-01

This article describes the author's experience of incorporating Michael Novak's "Business as a Calling: Work and the Examined Life" into a Business Law course. The author views it as a positive addition to the course, one that may be of interest to her colleagues at other institutions. Accordingly, after an overview of Novak's analysis in…

Competing Classical and Quantum Effects in Shape Relaxation of a Metallic Island

NASA Technical Reports Server (NTRS)

Okamoto, Rowland H.; Chen, D.; Yamada, T.

2002-01-01

Pb islands grown on a silicon substrate transform at room temperature from the initially flattop facet geometry into an unusual ring, shape with a volume-preserving mass transport process catalysed by the tip electrical field of a scanning tunnelling microscope. The formation of such ring shape morphology results from the competing classical and quantum effects in the shape relaxation. The latter also leads to a sequential regrowth on alternating, strips of the same facet defined by the underlying substrate steps, showing for the first time the dynamical impact of the quantum size effect on the stability of a nanostructure.

Electrooxidation of morin hydrate at a Pt electrode studied by cyclic voltammetry.

PubMed

Masek, Anna; Chrzescijanska, Ewa; Zaborski, Marian

2014-04-01

The process and the kinetics of the electrochemical oxidation of morin in an anhydrous electrolyte have been investigated using cyclic and differential pulse voltammetry. The oxidation mechanism proceeds in sequential steps related to the hydroxyl groups in the three aromatic rings. The oxidation of the 2',4'dihydroxy moiety at the B ring of morin occurs first, at very low positive potentials, and is a one-electron, one-proton irreversible reaction. The rate constant, electron transfer coefficient and diffusion coefficients involved in the electrochemical oxidation of morin were determined. The influence of the deprotonation of the ring B hydroxyl moiety is related to the electron/proton donating capacity of morin and to its radical scavenging antioxidant activity. Copyright © 2013 Elsevier Ltd. All rights reserved.

β-Amino acid catalyzed asymmetric Michael additions: design of organocatalysts with catalytic acid/base dyad inspired by serine proteases.

PubMed

Yang, Hui; Wong, Ming Wah

2011-09-16

A new type of chiral β-amino acid catalyst has been computationally designed, mimicking the enzyme catalysis of serine proteases. Our catalyst approach is based on the bioinspired catalytic acid/base dyad, namely, a carboxyl and imidazole pair. DFT calculations predict that this designed organocatalyst catalyzes Michael additions of aldehydes to nitroalkenes with excellent enantioselectivities and remarkably high anti diastereoselectivities. The unusual stacked geometry of the enamine intermediate, hydrogen bonding network, and the adoption of an exo transition state are the keys to understand the stereoselectivity. © 2011 American Chemical Society

Synthesis and structure of a ferric complex of 2,6-di(1H-pyrazol-3-yl)pyridine and its excellent performance in the redox-controlled living ring-opening polymerization of ε-caprolactone.

PubMed

Fang, Yang-Yang; Gong, Wei-Jie; Shang, Xiu-Juan; Li, Hong-Xi; Gao, Jun; Lang, Jian-Ping

2014-06-14

The reaction of FeCl3 with a pincer ligand, 2,6-di(1H-pyrazol-3-yl)pyridine (bppyH2), produced a mononuclear Fe(III) complex [Fe(bppyH2)Cl3] (1), which could be reduced to the corresponding Fe(II) dichloride complex [Fe(bppyH2)Cl2] (2) by suitable reducing agents such as Cp2Co or Fe powder. 1 and 2 exhibited a reversible transformation from each other with appropriate redox reagents. 1 could be utilized as a pre-catalyst to initiate the ring-opening polymerization of ε-caprolactone in the presence of alcohol but did not work. The 1/alcohol system displayed characteristics of a well-controlled polymerization with the resulting poly(ε-caprolactone) having low molecular weight distributions, a linear tendency of molecular weight evolution with conversion, and polymer growth observed for the sequential additions of ε-caprolactone monomer to the polymerization reaction. The polymerization was completely turned off by the in situ reduction of the catalytic Fe center via Cp2Co and then turned back upon the addition of [Cp2Fe]PF6. The rate of polymerization was modified by switching in situ between the Fe(III) and Fe(II) species.

Gear tooth stress measurements of two helicopter planetary stages

NASA Technical Reports Server (NTRS)

Krantz, Timothy L.

1992-01-01

Two versions of the planetary reduction stages from U.S. Army OH-58 helicopter main rotor transmissions were tested at NASA Lewis. One sequential and one nonsequential planetary were tested. Sun gear and ring gear teeth strains were measured, and stresses were calculated from the strains. The alternating stress at the fillet of both the loaded and unloaded sides of the teeth and at the root of the sun gear teeth are reported. Typical stress variations as the gear tooth moves through mesh are illustrated. At the tooth root location of the thin rimmed sun gear, a significant stress was produced by a phenomenon other than the passing of a planet gear. The load variation among the planets was studied. Each planet produced its own distinctive load distribution on the ring and sun gears. The load variation was less for a three planet, nonsequential design as compared to that of a four planet, sequential design. The reported results enhance the data base for gear stress levels and provide data for the validation of analytical methods.

An Integral Part of the Frederick Community—Michael Dean | Poster

Cancer.gov

For more than 30 years, Michael Dean, Ph.D., has been an integral part of the NCI at Frederick community. In addition to studying several different aspects of genomics and cancer research, he has worked with the Werner H. Kirsten Student Intern Program and also volunteered his time with Mission of Mercy, a community-based organization providing free healthcare and free prescription medications to the uninsured and under-insured.

How does climate influence xylem morphogenesis over the growing season? Insights from long-term intra-ring anatomy in Picea abies

PubMed Central

Fonti, Patrick; von Arx, Georg; Carrer, Marco

2017-01-01

Background and Aims During the growing season, the cambium of conifer trees produces successive rows of xylem cells, the tracheids, that sequentially pass through the phases of enlargement and secondary wall thickening before dying and becoming functional. Climate variability can strongly influence the kinetics of morphogenetic processes, eventually affecting tracheid shape and size. This study investigates xylem anatomical structure in the stem of Picea abies to retrospectively infer how, in the long term, climate affects the processes of cell enlargement and wall thickening. Methods Tracheid anatomical traits related to the phases of enlargement (diameter) and wall thickening (wall thickness) were innovatively inspected at the intra-ring level on 87-year-long tree-ring series in Picea abies trees along a 900 m elevation gradient in the Italian Alps. Anatomical traits in ten successive tree-ring sectors were related to daily temperature and precipitation data using running correlations. Key Results Close to the altitudinal tree limit, low early-summer temperature negatively affected cell enlargement. At lower elevation, water availability in early summer was positively related to cell diameter. The timing of these relationships shifted forward by about 20 (high elevation) to 40 (low elevation) d from the first to the last tracheids in the ring. Cell wall thickening was affected by climate in a different period in the season. In particular, wall thickness of late-formed tracheids was strongly positively related to August–September temperature at high elevation. Conclusions Morphogenesis of tracheids sequentially formed in the growing season is influenced by climate conditions in successive periods. The distinct climate impacts on cell enlargement and wall thickening indicate that different morphogenetic mechanisms are responsible for different tracheid traits. Our approach of long-term and high-resolution analysis of xylem anatomy can support and extend short-term xylogenesis observations, and increase our understanding of climate control of tree growth and functioning under different environmental conditions. PMID:28130220

­Back-to-back mechanisms drive actomyosin ring closure during Drosophila embryo cleavage

PubMed Central

2016-01-01

Contraction of actomyosin rings during cytokinesis is typically attributed to actin filaments sliding toward each other via Myosin-2 motor activity. However, rings constrict in some cells in the absence of Myosin-2 activity. Thus, ring closure uses Myosin-2–dependent and –independent mechanisms. But what the Myosin-2–independent mechanisms are, and to what extent they are sufficient to drive closure, remains unclear. During cleavage in Drosophila melanogaster embryos, actomyosin rings constrict in two sequential and mechanistically distinct phases. We show that these phases differ in constriction speed and are genetically and pharmacologically separable. Further, Myosin-2 activity is required for slow constriction in “phase 1” but is largely dispensable for fast constriction in “phase 2,” and F-actin disassembly is only required for fast constriction in phase 2. Switching from phase 1 to phase 2 seemingly relies on the spatial organization of F-actin as controlled by Cofilin, Anillin, and Septin. Our work shows that fly embryos present a singular opportunity to compare separable ring constriction mechanisms, with varying Myosin-2 dependencies, in one cell type and in vivo. PMID:27799369

Reactivity measurement in estimation of benzoquinone and benzoquinone derivatives’ allergenicity

PubMed Central

Mbiya, Wilbes; Chipinda, Itai; Simoyi, Reuben H.; Siegel, Paul D.

2015-01-01

Benzoquinone (BQ) and benzoquinone derivatives (BQD) are used in the production of dyes and cosmetics. While BQ, an extreme skin sensitizer, is an electrophile known to covalently modify proteins via Michael Addition (MA) reaction whilst halogen substituted BQD undergo nucleophilic vinylic substitution (SNV) mechanism onto amine and thiol moieties on proteins, the allergenic effects of adding substituents on BQ have not been reported. The effects of inserting substituents on the BQ ring has not been studied in animal assays. However, mandated reduction/elimination of animals used in cosmetics testing in Europe has led to an increased need for alternatives for the prediction of skin sensitization potential. Electron withdrawing and electron donating substituents on BQ were assessed for effects on BQ reactivity toward nitrobenzene thiol (NBT). The NBT binding studies demonstrated that addition of EWG to BQ as exemplified by the chlorine substituted BQDs increased reactivity while addition of EDG as in the methyl substituted BQDs reduced reactivity. BQ and BQD skin allerginicity was evaluated in the murine local lymph node assay (LLNA). BQD with electron withdrawing groups had the highest chemical potency followed by unsubstituted BQ and the least potent were the BQD with electron donating groups. The BQD results demonstrate the impact of inductive effects on both BQ reactivity and allergenicity, and suggest the potential utility of chemical reactivity data for electrophilic allergen identification and potency ranking. PMID:26612505

Eco-friendly polyethylene glycol promoted Michael addition reactions of α,β-unsaturated carbonyl compounds

EPA Science Inventory

Abstract- Intra- and inter-nucleophilic addition reactions of different unsaturated compounds were found to be highly effective without any additives in PEG-400 as a recyclable reaction medium under neutral conditions.

Forming a Two-Ring Polycyclic Aromatic Hydrocarbon without a Benzene Intermediate: the Reaction of Propargyl with Acetylene

NASA Astrophysics Data System (ADS)

Osborn, David; Savee, John; Selby, Talitha; Welz, Oliver; Taatjes, Craig

The reaction of acetylene (HCCH) with a resonance-stabilized free radical is a commonly invoked mechanism for the generation of polycyclic aromatic hydrocarbons (PAH), which are likely precursors of soot particles in combustion. In this work, we examine the sequential addition of acetylene to the propargyl radical (H2CCCH) at temperatures of 800 and 1000 K. Using time-resolved multiplexed photoionization mass spectrometry with tunable ionizing radiation, we identified the isomeric forms of the C5H5 and C7H7 intermediates in this reaction sequence, and confirmed that the final C9H8 product is the two-ring aromatic compound indene. We identified two different resonance-stabilized C5H5 intermediates, with different temperature dependencies. Furthermore, the C7H7 intermediate is the tropyl radical (c-C7H7) , not the benzyl radical (C6H5CH2) , as is usually assumed in combustion environments. These experimental results are in general agreement with the latest electronic structure / master equation results of da Silva et al. This work shows a pathway for PAH formation that bypasses benzene / benzyl intermediates.

Ring/Flash: Telephone Skills for Deaf and Hard of Hearing Students. Teacher Guide and Student Workbook.

ERIC Educational Resources Information Center

Deyo, David

The curriculum is designed to teach elementary level deaf and hard of hearing students telephone skills. The program provides sequential activities to teach both voice and TDD communication methods. Suggested activities are detailed for each skill. The first unit on TDD communication is divided into the following sections: keyboard skills,…

KSC-04pd0614

NASA Image and Video Library

2004-03-24

KENNEDY SPACE CENTER, FLA. -- United Space Alliance workers Michael Williams and Ginger Morrison stitch together pieces of insulation blankets inside the ring that fits in the nose cap of Discovery. The blankets consist of layered, pure silica felt sandwiched between a layer of silica fabric (the hot side) and a layer of S-Glass fabric. The blankets are semi-rigid and can be made as large as 30 inches by 30 inches. The blanket is through-stitched with pure silica thread in a 1-inch grid pattern. After fabrication, the blanket is bonded directly to the vehicle structure and finally coated with a high purity silica coating that improves erosion resistance.

KSC-04pd0613

NASA Image and Video Library

2004-03-24

KENNEDY SPACE CENTER, FLA. -- United Space Alliance workers Ginger Morrison and Michael Williams stitch together pieces of insulation blankets inside the ring that fits in the nose cap of Discovery. The blankets consist of layered, pure silica felt sandwiched between a layer of silica fabric (the hot side) and a layer of S-Glass fabric. The blanket is through-stitched with pure silica thread in a 1-inch grid pattern. After fabrication, the blanket is bonded directly to the vehicle structure and finally coated with a high purity silica coating that improves erosion resistance. The blankets are semi-rigid and can be made as large as 30 inches by 30 inches.

KSC-04PD-0613

NASA Technical Reports Server (NTRS)

2004-01-01

KENNEDY SPACE CENTER, FLA. -- United Space Alliance workers Ginger Morrison and Michael Williams stitch together pieces of insulation blankets inside the ring that fits in the nose cap of Discovery. The blankets consist of layered, pure silica felt sandwiched between a layer of silica fabric (the hot side) and a layer of S-Glass fabric. The blanket is through-stitched with pure silica thread in a 1-inch grid pattern. After fabrication, the blanket is bonded directly to the vehicle structure and finally coated with a high purity silica coating that improves erosion resistance. The blankets are semi-rigid and can be made as large as 30 inches by 30 inches.

KSC-04PD-0616

NASA Technical Reports Server (NTRS)

2004-01-01

KENNEDY SPACE CENTER, FLA. -- United Space Alliance workers Ginger Morrison and Michael Williams stitch together pieces of insulation blankets inside the ring that fits in the nose cap of Discovery. The blankets consist of layered, pure silica felt sandwiched between a layer of silica fabric (the hot side) and a layer of S-Glass fabric. The blankets are semi-rigid and can be made as large as 30 inches by 30 inches. The blanket is through- stitched with pure silica thread in a 1-inch grid pattern. After fabrication, the blanket is bonded directly to the vehicle structure and finally coated with a high purity silica coating that improves erosion resistance.

KSC-04pd0616

NASA Image and Video Library

2004-03-24

KENNEDY SPACE CENTER, FLA. -- United Space Alliance workers Ginger Morrison and Michael Williams stitch together pieces of insulation blankets inside the ring that fits in the nose cap of Discovery. The blankets consist of layered, pure silica felt sandwiched between a layer of silica fabric (the hot side) and a layer of S-Glass fabric. The blankets are semi-rigid and can be made as large as 30 inches by 30 inches. The blanket is through-stitched with pure silica thread in a 1-inch grid pattern. After fabrication, the blanket is bonded directly to the vehicle structure and finally coated with a high purity silica coating that improves erosion resistance.

KSC-04PD-0614

NASA Technical Reports Server (NTRS)

2004-01-01

KENNEDY SPACE CENTER, FLA. -- United Space Alliance workers Michael Williams and Ginger Morrison stitch together pieces of insulation blankets inside the ring that fits in the nose cap of Discovery. The blankets consist of layered, pure silica felt sandwiched between a layer of silica fabric (the hot side) and a layer of S-Glass fabric. The blankets are semi-rigid and can be made as large as 30 inches by 30 inches. The blanket is through- stitched with pure silica thread in a 1-inch grid pattern. After fabrication, the blanket is bonded directly to the vehicle structure and finally coated with a high purity silica coating that improves erosion resistance.

Synthesis of peptides containing overlapping lanthionine bridges on the solid phase: an analogue of rings D and E of the lantibiotic nisin.

PubMed

Mothia, Begum; Appleyard, Antony N; Wadman, Sjoerd; Tabor, Alethea B

2011-08-19

A methodology for the solid-phase synthesis of the overlapping lanthionine bridges found in many lantibiotics has been developed. A novel Teoc/TMSE-protected lanthionine derivative has been synthesized, and this lanthionine, and an Aloc/allyl-protected lanthionine derivative, have been incorporated into a linear peptide using solid-phase peptide synthesis. Selective deprotection of the silyl protecting groups, followed by sequential cyclization, deprotection of the allyl protecting groups, and further cyclization, enabled the regioselective formation of an analogue of rings D and E of nisin. © 2011 American Chemical Society

Br2 molecular elimination in photolysis of (COBr)2 at 248 nm by using cavity ring-down absorption spectroscopy: a photodissociation channel being ignored.

PubMed

Wu, Chia-Ching; Lin, Hsiang-Chin; Chang, Yuan-Bin; Tsai, Po-Yu; Yeh, Yu-Ying; Fan, He; Lin, King-Chuen; Francisco, J S

2011-12-21

A primary dissociation channel of Br(2) elimination is detected following a single-photon absorption of (COBr)(2) at 248 nm by using cavity ring-down absorption spectroscopy. The technique contains two laser beams propagating in a perpendicular configuration. The tunable laser beam along the axis of the ring-down cell probes the Br(2) fragment in the B(3)Π(ou)(+)-X(1)Σ(g)(+) transition. The measurements of laser energy- and pressure-dependence and addition of a Br scavenger are further carried out to rule out the probability of Br(2) contribution from a secondary reaction. By means of spectral simulation, the ratio of nascent vibrational population for v = 0, 1, and 2 levels is evaluated to be 1:(0.65 ± 0.09):(0.34 ± 0.07), corresponding to a Boltzmann vibrational temperature of 893 ± 31 K. The quantum yield of the ground state Br(2) elimination reaction is determined to be 0.11 ± 0.06. With the aid of ab initio potential energy calculations, the pathway of molecular elimination is proposed on the energetic ground state (COBr)(2) via internal conversion. A four-center dissociation mechanism is followed synchronously or sequentially yielding three fragments of Br(2) + 2CO. The resulting Br(2) is anticipated to be vibrationally hot. The measurement of a positive temperature effect supports the proposed mechanism.

The Michael Reaction

NASA Astrophysics Data System (ADS)

Poon, Thomas; Mundy, Bradford P.; Shattuck, Thomas W.

2002-02-01

A brief account of the Michael reaction is provided, illustrating its versatility as a topic in undergraduate chemistry courses. Included is a short biography of the reaction's namesake, examples of its use in organic synthesis, and its unique role in the defense mechanism of the bacterium Micromonospora echinospora. A computational rationale for the selectivity of 1,4 versus 1,2 addition of nucleophiles to a,b-unsaturated carbonyls is discussed and links to animations suitable for an introductory organic chemistry course are provided.

Multistep Dst development and ring current composition changes during the 4-6 June 1991 magnetic storm

NASA Astrophysics Data System (ADS)

Kozyra, J. U.; Liemohn, M. W.; Clauer, C. R.; Ridley, A. J.; Thomsen, M. F.; Borovsky, J. E.; Roeder, J. L.; Jordanova, V. K.; Gonzalez, W. D.

2002-08-01

The 4-6 June 1991 magnetic storm, which occurred during solar maximum conditions, is analyzed to investigate two observed features of magnetic storms that are not completely understood: (1) the mass-dependent decay of the ring current during the early recovery phase and (2) the role of preconditioning in multistep ring current development. A kinetic ring current drift-loss model, driven by dynamic fluxes at the nightside outer boundary, was used to simulate this storm interval. A strong partial ring current developed and persisted throughout the main and early recovery phases. The majority of ions in the partial ring current make one pass through the inner magnetosphere on open drift paths before encountering the dayside magnetopause. The ring current exhibited a three-phase decay in this storm. A short interval of charge-exchange loss constituted the first phase of the decay followed by a classical two-phase decay characterized by an abrupt transition between two very different decay timescales. The short interval dominated by charge-exchange loss occurred because an abrupt northward turning of the interplanetary magnetic field (IMF) trapped ring current ions on closed trajectories, and turned-off sources and ``flow-out'' losses. If this had been the end of the solar wind disturbance, decay timescales would have gradually lengthened as charge exchange preferentially removed the short-lived species; a distinctive two-phase decay would not have resulted. However, the IMF turned weakly southward, drift paths became open, and a standard two-phase decay ensued as the IMF rotated slowly northward again. As has been shown before, a two-phase decay is produced as open drift paths are converted to closed in a weakening convection electric field, driving a transition from the fast flow-out losses associated with the partial ring current to the slower charge-exchange losses associated with the trapped ring current. The open drift path geometry during the main phase and during phase 1 of the two-phase decay has important consequences for the evolution of ring current composition and for preconditioning issues. In this particular storm, ring current composition changes measured by the Combined Release and Radiation Effects Satellite (CRRES) during the main and recovery phase of the storm resulted largely from composition changes in the plasma sheet transmitted into the inner magnetosphere along open drift paths as the magnetic activity declined. Possible preconditioning elements were investigated during the multistep development of this storm, which was driven by the sequential arrival of three southward IMF Bz intervals of increasing peak strength. In each case, previous intensifications (preexisting ring currents) were swept out of the magnetosphere by the enhanced convection associated with the latest intensification and did not act as a significant preconditioning element. However, plasma sheet characteristics varied significantly between subsequent intensifications, altering the response of the magnetosphere to the sequential solar wind drivers. A denser plasma sheet (ring current source population) appeared during the second intensification, compensating for the weaker IMF Bz at this time and producing a minimum pressure-corrected Dst* value comparable to the third intensification (driven by stronger IMF Bz but a lower density plasma sheet source). The controlling influence of the plasma sheet dynamics on the ring current dynamics and its role in altering the inner magnetospheric response to solar wind drivers during magnetic storms adds a sense of urgency to understanding what processes produce time-dependent responses in the plasma sheet density, composition, and temperature.

Biogenetically inspired approach to the Strychnos alkaloids. Concise syntheses of (+/-)-akuammicine and (+/-)-strychnine.

PubMed

Ito, M; Clark, C W; Mortimore, M; Goh, J B; Martin, S F

2001-08-22

A linear synthesis of the indole alkaloid (+/-)-akuammicine (2) was completed by a novel sequence of reactions requiring only 10 steps from commercially available starting materials. The approach features a tandem vinylogous Mannich addition and an intramolecular hetero Diels-Alder reaction to rapidly assemble the pentacyclic heteroyohimboid derivative 8 from the readily available hydrocarboline 6. Oxidation of the E ring of 8 gave the lactone 9 that was converted into deformylgeissoschizine (11). The subsequent elaboration of 11 into 2 was effected by a biomimetically patterned transformation that involved sequential oxidation and base-induced skeletal reorganization. A variation of these tactics was then applied to the synthesis of the C(18) hydroxylated akuammicine derivative 36. Because 36 had previously been converted into strychnine (1) in four steps, its preparation constitutes a concise, formal synthesis of this complex alkaloid.

Substrate Control in Stereoselective Lanthionine Biosynthesis

PubMed Central

Tang, Weixin; Jiménez-Osés, Gonzalo; Houk, K. N.; van der Donk, Wilfred A.

2014-01-01

Enzymes are typically highly stereoselective catalysts that enforce a reactive conformation on their native substrates. We report here a rare example where the substrate controls the stereoselectivity of an enzyme-catalyzed Michael-type addition during the biosynthesis of lanthipeptides. These natural products contain thioether crosslinks formed by cysteine attack on dehydrated Ser and Thr residues. We demonstrate that several lanthionine synthetases catalyze highly selective anti additions in which the substrate (and not the enzyme) determines whether the addition occurs from the Re or Si face. A single point mutation in the peptide substrate completely inverted the stereochemical outcome of the enzymatic modification. Quantum mechanical calculations reproduced the experimentally observed selectivity and suggest that conformational restraints imposed by the amino acid sequence on the transition states determine the face selectivity of the Michael-type cyclization. PMID:25515891

Organocatalytic, enantioselective synthesis of benzoxaboroles via Wittig/oxa-Michael reaction Cascade of α-formyl boronic acids† †Electronic supplementary information (ESI) available. CCDC 1487136. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c6sc04522g Click here for additional data file. Click here for additional data file.

PubMed Central

Hazra, Gurupada; Maity, Sanjay; Bhowmick, Sudipto

2017-01-01

An unprecedented enantioselective synthesis of 3-substituted benzoxaboroles has been developed. An in situ generated ortho-boronic acid containing chalcone provides the chiral benzoxaboroles via an asymmetric oxa-Michael addition of hydroxyl group attached to the boronic acid triggered by the cinchona alkaloid based chiral amino-squaramide catalysts. In general, good yields with good to excellent enantioselectivities (up to 99%) were obtained. The resulting benzoxaboroles were converted to the corresponding chiral β-hydroxy ketones without affecting the enantioselectivity. PMID:28451370

Merging gold and organocatalysis: a facile asymmetric synthesis of annulated pyrroles.

PubMed

Hack, Daniel; Loh, Charles C J; Hartmann, Jan M; Raabe, Gerhard; Enders, Dieter

2014-04-01

The combination of cinchona-alkaloid-derived primary amine and Au(I) -phosphine catalysts allowed the selective C-H functionalization of two adjacent carbon atoms of pyrroles under mild reaction conditions. This sequential dual activation provides seven-membered-ring-annulated pyrrole derivatives in excellent yields and enantioselectivities. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Stereospecific ring expansion from orthocyclophanes with central chirality to metacyclophanes with planar chirality.

PubMed

Ishida, Naoki; Sawano, Shota; Murakami, Masahiro

2014-01-01

Carbon-carbon bonds constitute the major framework of organic molecules and carbon-hydrogen bonds are abundant in their peripheries. Such nonpolar σ-bonds are thermodynamically stable and kinetically inert in general. Nonetheless, selective activation of those ubiquitous bonds may offer a straightforward method to construct and/or functionalize organic skeletons. Herein we describe ring expansion from orthocyclophanes to metacyclophanes occurring upon sequential action of light and a metal catalyst. Formally, specific non-strained carbon-hydrogen and carbon-carbon bonds are cleaved and exchanged without elimination of any leaving groups. Notably, the product is energetically uphill from the starting material, but the endergonic photocyclization step makes it possible to drive the transformation forward. The ring expansion is extended to the stereospecific synthesis of metacyclophanes possessing planar chirality, during which central chirality on a tertiary carbon is transferred to planar chirality.

A Promiscuous De Novo Retro-Aldolase Catalyzes Asymmetric Michael Additions via Schiff Base Intermediates.

PubMed

Garrabou, Xavier; Beck, Tobias; Hilvert, Donald

2015-05-04

Recent advances in computational design have enabled the development of primitive enzymes for a range of mechanistically distinct reactions. Here we show that the rudimentary active sites of these catalysts can give rise to useful chemical promiscuity. Specifically, RA95.5-8, designed and evolved as a retro-aldolase, also promotes asymmetric Michael additions of carbanions to unsaturated ketones with high rates and selectivities. The reactions proceed by amine catalysis, as indicated by mutagenesis and X-ray data. The inherent flexibility and tunability of this catalyst should make it a versatile platform for further optimization and/or mechanistic diversification by directed evolution. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Michael Addition Reactions between Chiral Equivalents of a Nucleophilic Glycine and (S)- or (R)-3-[(E)-Enoyl]-4-phenyl-1,3-oxazolidin-2-ones as a General Method for Efficient Preparation of β-Substituted Pyroglutamic Acids. Case of Topographically Controlled Stereoselectivity

PubMed Central

Soloshonok*, Vadim A.; Cai, Chaozhong; Yamada, Takeshi; Ueki, Hisanori; Ohfune, Yasufumi; Hruby, Victor J.

2006-01-01

This paper describes a systematic study of addition reactions between the chiral Ni(II) complex of the Schiff base of glycine with (S)-o-[N-(N-benzylprolyl)amino]benzophenone and (S)- or (R)-3-[(E)-enoyl]-4-phenyl-1,3-oxazolidin-2-ones as a general and synthetically efficient approach to β-substituted pyroglutamic acids and relevant compounds. These reactions were shown to occur at room temperature in the presence of nonchelating organic bases and, most notably, with very high (>98% diastereomeric excess (de)) stereoselectivity at both newly formed stereogenic centers. The stereochemical outcome of the reactions was found to be overwhelmingly controlled by the stereochemical preferences of the Michael acceptors, and the chirality of the glycine complex influenced only the reaction rate. Thus, in the reactions of both the (S)-configured Ni(II) complex and the Michael acceptors, the reaction rates were exceptionally high, allowing preparation of the corresponding products with virtually quantitative (>98%) chemical and stereochemical yields. In contrast, reactions of the (S)-configured Ni(II) complex and (R)-configured Michael acceptors proceeded at noticeably lower rates, but the addition products were obtained in high diastereo-and enantiomeric purity. To rationalize the remarkably high and robust stereoselectivity observed in these reactions, we consider an enzyme–substrate-like mode of interaction involing a topographical match or mismatch of two geometric figures. Excellent chemical and stereochemical yields, combined with the simplicity and operational convenience of the experimental procedures, render the present method of immediate use for preparing various β-substituted pyroglutamic acids and related compounds. PMID:16248672

Michael addition reactions between chiral equivalents of a nucleophilic glycine and (S)- or (R)-3-[(E)-enoyl]-4-phenyl-1,3-oxazolidin-2-ones as a general method for efficient preparation of beta-substituted pyroglutamic acids. Case of topographically controlled stereoselectivity.

PubMed

Soloshonok, Vadim A; Cai, Chaozhong; Yamada, Takeshi; Ueki, Hisanori; Ohfune, Yasufumi; Hruby, Victor J

2005-11-02

This paper describes a systematic study of addition reactions between the chiral Ni(II) complex of the Schiff base of glycine with (S)-o-[N-(N-benzylprolyl)amino]benzophenone and (S)- or (R)-3-[(E)-enoyl]-4-phenyl-1,3-oxazolidin-2-ones as a general and synthetically efficient approach to beta-substituted pyroglutamic acids and relevant compounds. These reactions were shown to occur at room temperature in the presence of nonchelating organic bases and, most notably, with very high (>98% diastereomeric excess (de)) stereoselectivity at both newly formed stereogenic centers. The stereochemical outcome of the reactions was found to be overwhelmingly controlled by the stereochemical preferences of the Michael acceptors, and the chirality of the glycine complex influenced only the reaction rate. Thus, in the reactions of both the (S)-configured Ni(II) complex and the Michael acceptors, the reaction rates were exceptionally high, allowing preparation of the corresponding products with virtually quantitative (>98%) chemical and stereochemical yields. In contrast, reactions of the (S)-configured Ni(II) complex and (R)-configured Michael acceptors proceeded at noticeably lower rates, but the addition products were obtained in high diastereo- and enantiomeric purity. To rationalize the remarkably high and robust stereoselectivity observed in these reactions, we consider an enzyme-substrate-like mode of interaction involving a topographical match or mismatch of two geometric figures. Excellent chemical and stereochemical yields, combined with the simplicity and operational convenience of the experimental procedures, render the present method of immediate use for preparing various beta-substituted pyroglutamic acids and related compounds.

Acid-Activatable Michael-Type Fluorescent Probes for Thiols and for Labeling Lysosomes in Live Cells.

PubMed

Dai, Chun-Guang; Du, Xiao-Jiao; Song, Qin-Hua

2015-12-18

A Michael addition is usually taken as a base-catalyzed reaction. Most fluorescent probes have been designed to detect thiols in slightly alkaline solutions (pH 7-9). The sensing reactions of almost all Michael-type fluorescent probes for thiols are faster in a high pH solution than in a low pH solution. In this work, we synthesized a series of 7-substituted 2-(quinolin-2-ylmethylene)malonic acids (QMAs, substituents: NEt2, OH, H, Cl, or NO2) and their ethyl esters (QMEs) as Michael-type fluorescent probes for thiols. The sensing reactions of QMAs and QMEs occur in distinct pH ranges, pH < 7 for QMAs and pH > 7 for QMEs. On the basis of experimental and theoretic studies, we have clarified the distinct pH effects on the sensing reactivity between QMAs and QMEs and demonstrated that two QMAs (NEt2, OH) are highly sensitive and selective fluorescent probes for thiols in acidic solutions (pH < 7) and promising dyes that can label lysosomes in live cells.

How does climate influence xylem morphogenesis over the growing season? Insights from long-term intra-ring anatomy in Picea abies.

PubMed

Castagneri, Daniele; Fonti, Patrick; von Arx, Georg; Carrer, Marco

2017-04-01

During the growing season, the cambium of conifer trees produces successive rows of xylem cells, the tracheids, that sequentially pass through the phases of enlargement and secondary wall thickening before dying and becoming functional. Climate variability can strongly influence the kinetics of morphogenetic processes, eventually affecting tracheid shape and size. This study investigates xylem anatomical structure in the stem of Picea abies to retrospectively infer how, in the long term, climate affects the processes of cell enlargement and wall thickening. Tracheid anatomical traits related to the phases of enlargement (diameter) and wall thickening (wall thickness) were innovatively inspected at the intra-ring level on 87-year-long tree-ring series in Picea abies trees along a 900 m elevation gradient in the Italian Alps. Anatomical traits in ten successive tree-ring sectors were related to daily temperature and precipitation data using running correlations. Close to the altitudinal tree limit, low early-summer temperature negatively affected cell enlargement. At lower elevation, water availability in early summer was positively related to cell diameter. The timing of these relationships shifted forward by about 20 (high elevation) to 40 (low elevation) d from the first to the last tracheids in the ring. Cell wall thickening was affected by climate in a different period in the season. In particular, wall thickness of late-formed tracheids was strongly positively related to August-September temperature at high elevation. Morphogenesis of tracheids sequentially formed in the growing season is influenced by climate conditions in successive periods. The distinct climate impacts on cell enlargement and wall thickening indicate that different morphogenetic mechanisms are responsible for different tracheid traits. Our approach of long-term and high-resolution analysis of xylem anatomy can support and extend short-term xylogenesis observations, and increase our understanding of climate control of tree growth and functioning under different environmental conditions. © The Author 2017. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Sequential single shot X-ray photon correlation spectroscopy at the SACLA free electron laser

DOE PAGES

Lehmkühler, Felix; Kwaśniewski, Paweł; Roseker, Wojciech; ...

2015-11-27

In this study, hard X-ray free electron lasers allow for the first time to access dynamics of condensed matter samples ranging from femtoseconds to several hundred seconds. In particular, the exceptional large transverse coherence of the X-ray pulses and the high time-averaged flux promises to reach time and length scales that have not been accessible up to now with storage ring based sources. However, due to the fluctuations originating from the stochastic nature of the self-amplified spontaneous emission (SASE) process the application of well established techniques such as X-ray photon correlation spectroscopy (XPCS) is challenging. Here we demonstrate a single-shotmore » based sequential XPCS study on a colloidal suspension with a relaxation time comparable to the SACLA free-electron laser pulse repetition rate. High quality correlation functions could be extracted without any indications for sample damage. This opens the way for systematic sequential XPCS experiments at FEL sources.« less

Sequential single shot X-ray photon correlation spectroscopy at the SACLA free electron laser

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lehmkühler, Felix; Kwaśniewski, Paweł; Roseker, Wojciech

In this study, hard X-ray free electron lasers allow for the first time to access dynamics of condensed matter samples ranging from femtoseconds to several hundred seconds. In particular, the exceptional large transverse coherence of the X-ray pulses and the high time-averaged flux promises to reach time and length scales that have not been accessible up to now with storage ring based sources. However, due to the fluctuations originating from the stochastic nature of the self-amplified spontaneous emission (SASE) process the application of well established techniques such as X-ray photon correlation spectroscopy (XPCS) is challenging. Here we demonstrate a single-shotmore » based sequential XPCS study on a colloidal suspension with a relaxation time comparable to the SACLA free-electron laser pulse repetition rate. High quality correlation functions could be extracted without any indications for sample damage. This opens the way for systematic sequential XPCS experiments at FEL sources.« less

Test apparatus for locating shorts during assembly of electrical buses

NASA Technical Reports Server (NTRS)

Deboo, G. J.; Devine, D. L. (Inventor)

1981-01-01

A test apparatus is described for locating electrical shorts that is especially suited for use while an electrical circuit is being fabricated or assembled. A ring counter derives input pulses from a square wave oscillator. The outputs of the counter are fed through transistors to an array of light emitting diodes. Each diode is connected to an electrical conductor, such as a bus bar, that is to be tested. In the absence of a short between the electrical conductors the diodes are sequentially illuminated. When a short occurs, a comparator/multivibrator circuit triggers an alarm and stops the oscillator and the sequential energization of the diodes. The two diodes that remain illuminated identify the electrical conductors that are shorted.

Sequential Aldol Condensation – Transition Metal-Catalyzed Addition Reactions of Aldehydes, Methyl Ketones and Arylboronic Acids

PubMed Central

Liao, Yuan-Xi; Xing, Chun-Hui; Israel, Matthew; Hu, Qiao-Sheng

2011-01-01

Sequential aldol condensation of aldehydes with methyl ketones followed by transition metal-catalyzed addition reactions of arylboronic acids to form β-substituted ketones is described. By using the 1,1′-spirobiindane-7,7′-diol (SPINOL)-based phosphite, an asymmetric version of this type of sequential reaction, with up to 92% ee, was also realized. Our study provided an efficient method to access β-substituted ketones and might lead to the development of other sequential/tandem reactions with transition metal-catalyzed addition reactions as the key step. PMID:21417359

Sequential aldol condensation-transition metal-catalyzed addition reactions of aldehydes, methyl ketones, and arylboronic acids.

PubMed

Liao, Yuan-Xi; Xing, Chun-Hui; Israel, Matthew; Hu, Qiao-Sheng

2011-04-15

Sequential aldol condensation of aldehydes with methyl ketones followed by transition metal-catalyzed addition reactions of arylboronic acids to form β-substituted ketones is described. By using the 1,1'-spirobiindane-7,7'-diol (SPINOL)-based phosphite, an asymmetric version of this type of sequential reaction, with up to 92% ee, was also realized. Our study provided an efficient method to access β-substituted ketones and might lead to the development of other sequential/tandem reactions with transition metal-catalyzed addition reactions as the key step. © 2011 American Chemical Society

HIGHLY DIASTEREOSELECTIVE MICHAEL REACTION UNDER SOLVENT-FREE CONDITIONS USING MICROWAVES: CONJUGATE ADDITION OF FLAVANONE TO ITS CHALCONE PRECURSOR

EPA Science Inventory

Microwave-assisted reaction of 2'-hydroxychalcones in the presence of DBU resulted in the formation of hitherto unknown dimers by conjugate addition of the intermediate cyclic ketone to the starting enone.

The Redox-Active Chromium Phthalocyanine System: Isolation of Five Oxidation States from Pc4- CrI to Pc2- CrIII.

PubMed

Zhou, Wen; Thompson, John R; Leznoff, Clifford C; Leznoff, Daniel B

2017-02-16

The preparation and structural characterization of a series of chromium phthalocyanine complexes with multiple metal and ring oxidation states were achieved using PcCr II (1) (Pc=phthalocyanine) or PcCr II (THF) 2 (1⋅THF 2 ) as starting materials. The reaction of soluble 1⋅THF 2 with Br 2 or I 2 gave the PcCr III halide complexes PcCrX(THF) (X=I/I 3 , Br; 3, 4, respectively). Treatment of 1 with 0.5 equivalent of PhIO or air generated the dinuclear [PcCr(THF)] 2 (μ-O) (5), whereas the addition of one equivalent of AgSbF 6 to 1 resulted in oxidation to THF-solvated octahedral [PcCr III (THF) 2 ]SbF 6 (6). The reduction of 1 with three sequential equivalents of KEt 3 BH resulted in the isolation of [K(DME) 4 ][Pc 3- Cr II ] (7), [K(DME) 4 ] 2 [Pc 4- Cr II ] (8) and [K 6 (DME) 4 ][Pc 4- Cr I ] 2 (9), respectively. The reduced products are deep purple in colour, with visible absorption maxima between 500-580 nm. The ring-reduced complexes 7 and 8 are monomeric, whereas 9 is a 1D chain of dinuclear [PcCr] 2 units with intercalated K + cations and supported by Cr-Cr interactions of 2.988(2) Å. Addition of four equivalents of KC 8 resulted in the demetallated product PcK 2 (DME) 4 (10), which has a 1D chain structure. The isolation and structural characterization of new PcCr complexes spanning five oxidation states, including rare examples of crystalline reduced Pc-ring species emphasizes the broad redox activity and stability of phthalocyanine-based complexes. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Multicapillary Flow Reactor: Synthesis of 1,2,5-Thiadiazepane 1,1-Dioxide Library Utilizing One-Pot Elimination and Inter-/Intramolecular Double aza-Michael Addition Via Microwave-Assisted, Continuous-Flow Organic Synthesis (MACOS)

PubMed Central

Ullah, Farman; Zang, Qin; Javed, Salim; Zhou, Aihua; Knudtson, Christopher A.; Bi, Danse; Hanson, Paul R.; Organ, Michael G.

2013-01-01

A microwave-assisted, continuous-flow organic synthesis (MACOS) protocol for the synthesis of functionalized 1,2,5-thiadiazepane 1,1-dioxide library, utilizing a one-pot elimination and inter-/intramolecular double aza-Michael addition strategy is reported. The optimized protocol in MACOS was utilized for scale-out and further extended for library production using a multicapillary flow reactor. A 50-member library of 1,2,5-thiadiazepane 1,1-dioxides was prepared on a 100- to 300-mg scale with overall yields between 50 and 80% and over 90 % purity determined by proton nuclear magnetic resonance (1H-NMR) spectroscopy. PMID:24244871

Biography for Michael Rossol | NREL

Science.gov Websites

Biography for Michael Rossol Michael Rossol Michael Rossol Resource Data Scientist Michael.Rossol @nrel.gov | 303-275-3680 Michael Rossol is a member of the Systems Modeling team within the Systems Modeling

Michael Addition Polymerization of Trifunctional Amine and Acrylic Monomer: A Versatile Platform for Development of Biomaterials.

PubMed

Cheng, Weiren; Wu, Decheng; Liu, Ye

2016-10-10

Michael addition polymerizations of amines and acrylic monomers are versatile approaches to biomaterials for various applications. A combinatorial library of poly(β-amino ester)s and diverse poly(amido amine)s from diamines and diacrylates or bis(acrylamide)s have been reported, respectively. Furthermore, novel linear and hyperbranched polymers from Michael addition polymerizations of trifunctional amines and acrylic monomers significantly enrich this category of biomaterials. In this Review, we focus on the biomaterials from Michael addition polymerizations of trifunctional amines and acrylic monomers. First we discuss how the polymerization mechanisms, which are determined by the reactivity sequence of the three types of amines of trifunctional amines, i.e., secondary (2°) amines (original), primary (1°) amines, and 2° amines (formed), are affected by the chemistry of monomers, reaction temperature, and solvent. Then we update how to design and synthesize linear and hyperbranched polymers based on the understanding of polymerization mechanisms. Linear polymers containing 2° amines in the backbones can be obtained from polymerizations of diacrylates or bis(acrylamide)s with equimolar trifunctional amine, and several approaches, e.g., 2A 2 +BB'B″, A 3 +2BB'B', A 2 +BB'B″, to hyperbranched polymers are developed. Further through molecular design of monomers, conjugation of functional species to 2° amines in the backbones of linear polymers and the abundant terminal groups of hyperbranched polymers, the amphiphilicity of polymers can be adjusted, and additional stimuli, e.g., thermal, redox, reactive oxidation species (ROS), and light, responses can be integrated with the intrinsic pH response. Finally we discuss the applications of the polymers for gene/drug delivery and bioimaging through exploring their self-assemblies in various motifs, e.g., micelles, polyplexes particles/nanorings and hydrogels. Redox-responsive hyperbranched polymers can display 300 times higher in vitro gene transfection efficiency and provide a higher in vivo siRNA efficacy than PEI. Also redox-responsive micelle carriers can improve the efficacy of anticancer drug and the bioimaging contrast. Further molecular design and optimization of this category of polymers together with in vivo studies should provide safe and efficient biomaterials for clinical applications.

Astronaut Hall of Fame Induction Ceremony

NASA Image and Video Library

2017-05-19

In a ceremony set beneath Space Shuttle Atlantis, veteran astronauts C. Michael Foale and Ellen Ochoa are inducted into the U.S. Astronaut Hall of Fame. Foale and Ochoa make up the 16th group of space shuttle astronauts to be inducted into the Hall of Fame, and their addition to the group brings the total number of inductees to 95. More than 20 legendary astronauts were on hand to welcome the inductees, including: Robert Cabana, Dan Brandenstein, Al Worden, Charlie Duke, Charles Bolden, Michael Coats, Robert Crippen, Rhea Seddon, and Fred Gregory.

Enantioselective organocatalytic one-pot amination/aza-Michael/aldol condensation reaction sequence: synthesis of 3-pyrrolines with a quaternary stereocenter.

PubMed

Desmarchelier, Alaric; Coeffard, Vincent; Moreau, Xavier; Greck, Christine

2012-10-08

Primary amine-catalyzed direct conversion of α,α-disubstituted aldehydes into 3-pyrrolines with a quaternary stereocenter is reported. The one-pot enantioselective sequence is based on a α-amination, an aza-Michael addition of hydrazine, an aldol condensation dehydratation and proceeds with good yields and excellent levels of enantioselectivity. Synthetically attractive applications including the formation of aziridinopyrrolidine or epoxypyrrolidine derivatives with good yields and selectivities are also described. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A Microfluidic Chip Integrated with Hyaluronic Acid-Functionalized Electrospun Chitosan Nanofibers for Specific Capture and Nondestructive Release of CD44-Overexpressing Circulating Tumor Cells.

PubMed

Wang, Mengyuan; Xiao, Yunchao; Lin, Lizhou; Zhu, Xiaoyue; Du, Lianfang; Shi, Xiangyang

2018-04-18

Detection of circulating tumor cells (CTCs) in peripheral blood is of paramount significance for early-stage cancer diagnosis, estimation of cancer development, and individualized cancer therapy. Herein, we report the development of hyaluronic acid (HA)-functionalized electrospun chitosan nanofiber (CNF)-integrated microfludic platform for highly specific capture and nondestructive release of CTCs. First, electrospun CNFs were formed and modified with zwitterion of carboxyl betaine acrylamide (CBAA) via Michael addition reaction and then targeting ligand HA through a disulfide bond. We show that the formed nanofibers still maintain the smooth fibrous morphology after sequential surface modifications, have a good hemocompatibility, and exhibit an excellent antifouling property due to the CBAA modification. After being embedded within a microfluidic chip, the fibrous mat can capture cancer cells (A549, a human lung cancer cell line) with an efficiency of 91% at a flow rate of 1.0 mL/h. Additionally, intact release of cancer cells is able to be achieved after treatment with glutathione for 40 min to have a release efficiency of 90%. Clinical applications show that 9 of 10 nonsmall-cell lung cancer patients and 5 of 5 breast cancer patients are diagnosed to have CTCs (1 to 18 CTCs per mL of blood). Our results suggest that the developed microfluidic system integrated with functionalized CNF mats may be employed for effective CTCs capture for clinical diagnosis of cancer.

Evolution of the High Velocity X-Ray Emission in SN 1987A

NASA Astrophysics Data System (ADS)

Dewey, Daniel; Haberl, F.; Dwarkadas, V. V.; Burrows, D. N.; Park, S.

2011-01-01

Chandra HETG observations of SN 1987A in late 1999 showed very broad lines with observed FWHM of order 7000 km/s (Michael et al. 2002). At this time (SN day 4600) the blastwave was already interacting with the HII region around the progenitor and optical spots had recently appeared. High-resolution spectra taken from May 2003 ( day 5900) to the present by XMM-Newton and Chandra have been well fit by models with FWHM less than 2000 km/s (Zhekov et al. 2005; Dewey et al. 2008; Sturm et al 2010). The emission is increasingly dominated by these narrower components as the blastwave encounters more of the dense equatorial ring. However emission from the HII region out of the ring plane is still expected at late times and would contribute a high-velocity component to the spectra. We analyze 6 epochs of SN 1987A grating data and include an additional very broad component in the spectral model. We find that deep HETG 2007 data are better fit when one quarter of the flux comes from a component with FWHM 8500 km/s, and that RGS 2003 data show an improved fit with a very-broad fraction that is between the 1999 and 2007 values. Later data continue a progression to lower, but still significant, very-broad fractions. The measurements are discussed in terms of the density and extent of the out-of-plane HII region, hydrodynamical simulations, and 3D models of SN 1987A's emission. Support for this work was provided by NASA/USA through contract NAS8-03060 to the Smithsonian Astrophysical Observatory (SAO) and further SAO sub-contracts TM9-0004X to VVD (U Chicago) and SV3-73016 to MIT for support of the CXC.

In situ epoxide generation by dimethyldioxirane oxidation and the use of epichlorohydrin in the flow synthesis of a library of β-amino alcohols.

PubMed

Cossar, Peter J; Baker, Jennifer R; Cain, Nicholas; McCluskey, Adam

2018-04-01

The flow coupling of epichlorohydrin with substituted phenols, while efficient, limits the nature of the epoxide available for the development of focused libraries of β-amino alcohols. This limitation was encountered in the production of analogues of 1-(4-nitrophenoxy)-3-((2-((4-(trifluoromethyl)pyrimidin-2-yl)amino)ethyl)amino)propan-2-ol 1 , a potential antibiotic lead. The in situ (flow) generation of dimethyldoxirane (DMDO) and subsequent flow olefin epoxidation abrogates this limitation and afforded facile access to structurally diverse β-amino alcohols. Analogues of 1 were readily accessed either via (i) a flow/microwave hybrid approach, or (ii) a sequential flow approach. Key steps were the in situ generation of DMDO, with olefin epoxidation in typically good yields and a flow-mediated ring opening aminolysis to form an expanded library of β-amino alcohols 1 and 10a - 18g , resulting in modest ( 11a , 21%) to excellent ( 12g , 80%) yields. Alternatively flow coupling of epichlorohydrin with phenols 4a - 4m (22%-89%) and a Bi(OTf) 3 catalysed microwave ring opening with amines afforded a select range of β-amino alcohols, but with lower levels of aminolysis regiocontrol than the sequential flow approach.

In situ epoxide generation by dimethyldioxirane oxidation and the use of epichlorohydrin in the flow synthesis of a library of β-amino alcohols

PubMed Central

Cossar, Peter J.; Baker, Jennifer R.; Cain, Nicholas

2018-01-01

The flow coupling of epichlorohydrin with substituted phenols, while efficient, limits the nature of the epoxide available for the development of focused libraries of β-amino alcohols. This limitation was encountered in the production of analogues of 1-(4-nitrophenoxy)-3-((2-((4-(trifluoromethyl)pyrimidin-2-yl)amino)ethyl)amino)propan-2-ol 1, a potential antibiotic lead. The in situ (flow) generation of dimethyldoxirane (DMDO) and subsequent flow olefin epoxidation abrogates this limitation and afforded facile access to structurally diverse β-amino alcohols. Analogues of 1 were readily accessed either via (i) a flow/microwave hybrid approach, or (ii) a sequential flow approach. Key steps were the in situ generation of DMDO, with olefin epoxidation in typically good yields and a flow-mediated ring opening aminolysis to form an expanded library of β-amino alcohols 1 and 10a–18g, resulting in modest (11a, 21%) to excellent (12g, 80%) yields. Alternatively flow coupling of epichlorohydrin with phenols 4a–4m (22%–89%) and a Bi(OTf)3 catalysed microwave ring opening with amines afforded a select range of β-amino alcohols, but with lower levels of aminolysis regiocontrol than the sequential flow approach. PMID:29765627

Virtually complete control of simple and face diastereoselectivity in the Michael addition reactions between achiral equivalents of a nucleophilic glycine and (S)- or (R)-3-(E-enoyl)-4-phenyl-1,3-oxazolidin-2-ones: practical method for preparation of beta-substituted pyroglutamic acids and prolines.

PubMed

Soloshonok, Vadim A; Ueki, Hisanori; Tiwari, Rohit; Cai, Chaozhong; Hruby, Victor J

2004-07-23

This study demonstrates a new strategy for controlling the stereochemical outcome of the Michael addition reactions between nucleophilic glycine equivalents and alpha,beta-unsaturated carboxylic acid derivatives: The addition reactions between achiral Ni(II)-complex of the Schiff base of glycine with o-[N-alpha-pycolylamino]acetophenone and (S)- or (R)-3-(E-enoyl)-4-phenyl-1,3-oxazolidin-2-ones were shown to occur at room temperature in the presence of nonchelating organic bases and, most notably, with very high stereoselectivity at both newly formed stereogenic centers. Thus, the chiral 4-phenyl-1,3-oxazolidin-2-one moiety was found to control efficiently both face diastereoselectivities of the glycine derived enolate and the C,C double bond of the Michael acceptor. The new strategy developed in this work is methodologically superior to previous methods, most notably in terms of generality and synthetic efficiency. Excellent chemical yields and diastereoselectivities, combined with the simplicity of the experimental procedures, render the present method of immediate use for preparing various 3-substituted pyroglutamic acids and related amino acids (glutamic acids, glutamines, prolines, etc.) available via conventional transformations of the former.

Neutral O2 and Ion O2+ Sources from Rings into the Inner Magnetosphere

NASA Astrophysics Data System (ADS)

Elrod, M. K.; Johnson, R. E.; Cassidy, T. A.; Wilson, R. J.; Tseng, W.; Ip, W.

2009-12-01

The primary source of neutral O2 for Saturn’s magnetosphere is due to solar UV photons protons that produce O2 from H2O ice decomposition over the main rings as well as the tenuous F and G rings resulting in a tenuous O2 atmosphere (Johnson et. al. 2006). The O2 atmosphere is very thin to the point of being nearly collisionless. Our model of the atmosphere predict that as it interacts with the ring particles, the O2 is adsorbed and desorbed from the rings causing changes in the trajectories, which in turn, allows for a distribution of O2 from the rings throughout the magnetosphere (Tokar et. al. 2005; Tseng et. al. 2009). Predominately through photo-ionization and ion-exchange these O2 neutrals from the ice grains become a source for O2+ ions in the inner magnetosphere. Once the O2 becomes ionized to become O2+ the ions then follow the field lines. The ions interact with the ice particles in the rings to stick to the ring particles effectively reducing the ion density. As a result the ion density is greater over the Cassini Division and the area between the F and G ring where the optical depth due to the ice grain is less. Accordingly, the neutral O2 densities would tend to be high over the higher optical depth of the B and A main rings where the source rates are higher. Models of the neutral densities have shown high densities over the main rings, with a tail through the magnetosphere. Analysis of the CAPS (Cassini Plasma Spectrometer) data from the Saturn Orbit Insertion (SOI) in 2004 shows a peak in density over the Cassini Division and a higher peak in O2+ ion density between the F and G rings. References: Johnson, R.E., J.G. Luhmann, R.L. Tokar, M. Bouhram, J.J. Berthelier, E.C. Siler, J.F. Cooper, T.W. Hill, H.T. Smith, M. Michael, M. Liu, F.J. Crary, D.T. Young, "Production, Ionization and Redistribution of O2 Saturn's Ring Atmosphere" Icarus 180, 393-402 (2006).(pdf) Tokar, R.L., and 12 colleagues, 2005. Cassini Observations of the Thermal Plasma in the Vicinity of Saturn’s Main Rings and the F and G Rings. Geophys. Res. Lett. 32, doi:10.1029/2005GL022690. L14S04. Martens, H. R., Reisenfeld, D. B., Williams, J. D., Johnson, R.E., Smith H. T., “Observations of molecular oxygen ions in Saturn’s inner magnetosphere”. Geophy. Res. Lett. 2009. W.-L. Tseng, Ip, W.-H., Johnson, R. E., Cassidy, T. A., Elrod, M. K., “The Structure and Time Variability of the Ring atmosphere and ionosphere”. Geophy. Res. Lett. 2009.

New eco-friendly animal bone meal catalysts for preparation of chalcones and aza-Michael adducts

PubMed Central

2012-01-01

Abstract Two efficient reactions were successfully carried out using Animal Bone Meal (ABM) and potassium fluoride or sodium nitrate doped ABMs as new heterogeneous catalysts under very mild conditions. After preparation and characterization of the catalysts, we first report their use in a simple and convenient synthesis of various chalcones by Claisen–Schmidt condensation and then in an aza-Michael addition involving several synthesized chalcones with aromatic amines. All the reactions were carried out at room temperature in methanol; the chalcone synthesis was also achieved in water environment under microwave irradiation. Doping ABM enhances the rate and yield at each reaction. Catalytic activities are discussed and the ability to re-use the ABM is demonstrated. Results For Claisen–Schmidt the use of ABM alone, yields never exceeded 17%. In each entry, KF/ABM and NaNO3/ABM (79-97%) gave higher yields than using ABM alone under thermic condition. Also the reaction proceeded under microwave irradiation in good yields (72-94% for KF/ABM and 81-97% for NaNO3/ABM) and high purity. For aza-Michael addition the use of ABM doped with KF or NaNO3 increased the catalytic activity remarkably. The very high yields could be noted (84-95% for KF/ABM and 81-94% for NaNO3/ABM). Conclusion The present method is an efficient and selective procedure for the synthesis of chalcones an aza-Michael adducts. The ABM and doped ABMs are a new, inexpensive and attractive solid supports which can contribute to the development of catalytic processes and reduced environmental problems. PMID:22721409

Biliatresone, a Reactive Natural Toxin from Dysphania glomulifera and D. littoralis: Discovery of the Toxic Moiety 1,2-Diaryl-2-Propenone.

PubMed

Koo, Kyung A; Lorent, Kristin; Gong, Weilong; Windsor, Peter; Whittaker, Stephen J; Pack, Michael; Wells, Rebecca G; Porter, John R

2015-08-17

We identified a reactive natural toxin, biliatresone, from Dysphania glomulifera and D. littoralis collected in Australia that produces extrahepatic biliary atresia in a zebrafish model. Three additional isoflavonoids, including the known isoflavone betavulgarin, were also isolated. Biliatresone is in the very rare 1,2-diaryl-2-propenone class of isoflavonoids. The α-methylene of the 1,2-diaryl-2-propenone of biliatresone spontaneously reacts via Michael addition in the formation of water and methanol adducts. The lethal dose of biliatresone in a zebrafish assay was 1 μg/mL, while the lethal dose of synthetic 1,2-diaryl-2-propen-1-one was 5 μg/mL, suggesting 1,2-diaryl-2-propenone as the toxic Michael acceptor.

Biliatresone, a Reactive Natural Toxin from Dysphania glomulifera and D. littoralis: Discovery of the Toxic Moiety 1,2-Diaryl-2-Propenone

PubMed Central

Koo, Kyung A.; Lorent, Kristin; Gong, Weilong; Windsor, Peter; Whittaker, Stephen J.; Pack, Michael; Wells, Rebecca G.; Porter, John R.

2016-01-01

We identified a reactive natural toxin, biliatresone, from Dysphania glomulifera and D. littoralis collected in Australia that produces extrahepatic biliary atresia in a zebrafish model. Three additional isoflavonoids, including the known isoflavone betavulgarin, were also isolated. Biliatresone is in the very rare 1,2-diaryl-2-propenone class of isoflavonoids. The α-methylene of the 1,2-diaryl-2-propenone of biliatresone spontaneously reacts via Michael addition in the formation of water and methanol adducts. The lethal dose of biliatresone in a zebrafish assay was 1 μg/mL, while the lethal dose of synthetic 1,2-diaryl-2-propen-1-one was 5 μg/mL, suggesting 1,2-diaryl-2-propenone as the toxic Michael acceptor. PMID:26175131

Hexamethoxylated Monocarbonyl Analogues of Curcumin Cause G2/M Cell Cycle Arrest in NCI-H460 Cells via Michael Acceptor-Dependent Redox Intervention.

PubMed

Li, Yan; Zhang, Li-Ping; Dai, Fang; Yan, Wen-Jing; Wang, Hai-Bo; Tu, Zhi-Shan; Zhou, Bo

2015-09-09

Curcumin, derived from the dietary spice turmeric, holds promise for cancer prevention. This prompts much interest in investigating the action mechanisms of curcumin and its analogues. Two symmetrical hexamethoxy-diarylpentadienones (1 and 2) as cucumin analogues were reported to possess significantly enhanced cytotoxicity compared with the parent molecule. However, the detailed mechanisms remain unclear. In this study, compounds 1 and 2 were identified as the G2/M cell cycle arrest agents to mediate the cytotoxicity toward NCI-H460 cells via Michael acceptor-dependent redox intervention. Compared with curcumin, they could more easily induce a burst of reactive oxygen species (ROS) and collapse of the redox buffering system. One possible reason is that they could more effectively target intracellular TrxR to convert this antioxidant enzyme into a ROS promoter. Additionally, they caused up-regulation of p53 and p21 and down-regulation of redox-sensitive Cdc25C along with cyclin B1/Cdk1 in a Michael acceptor- and ROS-dependent fashion. Interestingly, in comparison with compound 2, compound 1 displayed a relatively weak ability to generate ROS but increased cell cycle arrest activity and cytotoxicity probably due to its Michael acceptor-dependent microtubule-destabilizing effect and greater GST-inhibitory activity, as well as its enhanced cellular uptake. This work provides useful information for understanding Michael acceptor-dependent and redox-mediated cytotoxic mechanisms of curcumin and its active analogues.

Ring-shaped dysphotopsia associated with posterior chamber phakic implantable collamer lenses with a central hole.

PubMed

Eom, Youngsub; Kim, Dae Wook; Ryu, Dongok; Kim, Jun-Heon; Yang, Seul Ki; Song, Jong Suk; Kim, Sug-Whan; Kim, Hyo Myung

2017-05-01

To evaluate the incidence of central hole-induced ring-shaped dysphotopsia after posterior chamber phakic implantable collamer lens (ICL) with central hole (hole ICL) implantation and to investigate the causes of central hole-induced dysphotopsia. The clinical study enrolled 29 eyes of 15 consecutive myopic patients implanted with hole ICL. The incidence of ring-shaped dysphotopsia after hole ICL implantation was evaluated. In the experimental simulation study, non-sequential ray tracing was used to construct myopic human eye models with hole ICL and ICL without a central hole (conventional ICL). Simulated retinal images measured in log-scale irradiance were compared between the two ICLs for an extended Lambertian light-emitting disc object 20 cm in diameter placed 2 m from the corneal vertex. To investigate the causes of hole-induced dysphotopsia, a series of retinal images were simulated using point sources at infinity with well-defined field angles (0 to -20°) and multiple ICL models. Of 29 eyes, 15 experienced ring-shaped dysphotopsia after hole ICL implantation. The simulation study using an extended Lambertian source showed that hole ICL-evoked ring-shaped dysphotopsia was formed at a retinal field angle of ±40°. Component-level analysis using a well-defined off-axis point source from infinity revealed that ring-shaped dysphotopsia was generated by stray light refraction from the inner wall of the hole and the posterior ICL surface. Hole ICL-evoked ring-shaped dysphotopsia was related to light refraction at the central hole structure. Surgeons are advised to explain to patients the possibility of ring-shaped dysphotopsia after hole ICL implantation. © 2016 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

Acute and chronic pain in calves after different methods of rubber-ring castration.

PubMed

Becker, Johanna; Doherr, Marcus G; Bruckmaier, Rupert M; Bodmer, Michèle; Zanolari, Patrik; Steiner, Adrian

2012-12-01

The goal of the present study was to evaluate the effect of different methods of rubber-ring castration on acute and chronic pain in calves. Sixty-three 4-6 week-old calves were randomly and sequentially allocated to one of five groups: Group RR (traditional rubber ring castration); group BRR (combination of one rubber ring with Burdizzo); group Rcut (one rubber ring applied with the scrotal tissue and rubber ring removed on day 9); group 3RR (three rubber rings placed one above the other around the scrotal neck); and group CO (controls; sham-castrated). All calves received 0.2 mL/kg bodyweight lidocaine 2%, injected into the spermatic cords and around the scrotal neck 15 min before castration. The presence of acute and chronic pain was assessed using plasma cortisol concentrations, response to palpation of scrotal area, time from castration until complete wound healing, and behavioural signs. Calves of group 3RR showed severe swelling and inflammation, and licking of the scrotal area occurred significantly more often than in groups Rcut and CO. Technique 3RR was discontinued for welfare reasons before the end of the study. All castration groups had significantly more pain upon palpation than calves of group CO, but palpation elicited markedly less pain in group Rcut than in the other castration groups. The most rapid healing time and shortest duration of chronic pain after castration was achieved in group Rcut. For welfare reasons, the Rcut technique should be considered as a valuable alternative to traditional rubber ring castration of calves at 4-6 weeks of age. Copyright © 2012 Elsevier Ltd. All rights reserved.

An unusual Michael-induced skeletal rearrangement of a bicyclo[3.3.1]nonane framework of phloroglucinols to a novel bioactive bicyclo[3.3.0]octane.

PubMed

Vidali, Veroniki P; Mitsopoulou, Kornilia P; Dakanali, Marianna; Demadis, Konstantinos D; Odysseos, Andreani D; Christou, Yiota A; Couladouros, Elias A

2013-11-01

A novel skeletal rearrangement of bicyclo[3.3.1]nonane-2,4,9-trione (16) to an unprecedented highly functionalized bicyclo[3.3.0]octane system (17), induced by an intramolecular Michael addition, is presented. This novel framework was found to be similarly active to hyperforin (1), against PC-3 cell lines. A mechanistic study was examined in detail, proposing a number of cascade transformations. Also, reactivity of the Δ(7,10)-double bond was examined under several conditions to explain the above results.

Sequential allylic substitution/Pauson-Khand reaction: a strategy to bicyclic fused cyclopentenones from MBH-acetates of acetylenic aldehydes.

PubMed

Raji Reddy, Chada; Kumaraswamy, Paridala; Singarapu, Kiran K

2014-09-05

An efficient approach for the construction of novel bicyclic fused cyclopentenones starting from Morita-Baylis-Hillman (MBH) acetates of acetylenic aldehydes with flexible scaffold diversity has been achieved using a two-step reaction sequence involving allylic substitution and the Pauson-Khand reaction. This strategy provided a facile access to various bicyclic cyclopentenones fused with either a carbocyclic or a heterocyclic ring system in good yield.

Metal-chelating polymers by anionic ring-opening polymerization and their use in quantitative mass cytometry.

PubMed

Illy, Nicolas; Majonis, Daniel; Herrera, Isaac; Ornatsky, Olga; Winnik, Mitchell A

2012-08-13

Metal-chelating polymers (MCPs) are important reagents for multiplexed immunoassays based on mass cytometry. The role of the polymer is to carry multiple copies of individual metal isotopes, typically as lanthanide ions, and to provide a reactive functionality for convenient attachment to a monoclonal antibody (mAb). For this application, the optimum combination of chain length, backbone structure, end group, pendant groups, and synthesis strategy has yet to be determined. Here we describe the synthesis of a new type of MCP based on anionic ring-opening polymerization of an activated cyclopropane (the diallyl ester of 1,1-cyclopropane dicarboxylic acid) using a combination of 2-furanmethanethiol and a phosphazene base as the initiator. This reaction takes place with rigorous control over molecular weight, yielding a polymer with a narrow molecular weight distribution, reactive pendant groups for introducing a metal chelator, and a functional end group with orthogonal reactivity for attaching the polymer to the mAbs. Following the ring-opening polymerization, a two-step transformation introduced diethylenetriaminepentaacetic acid (DTPA) chelating groups on each pendant group. The polymers were characterized by NMR, size exclusion chromatography (SEC), and thermogravimetric analysis (TGA). The binding properties toward Gd(3+) as a prototypical lanthanide (Ln) ion were also studied by isothermal titration calorimetry (ITC). Attachment to a mAb involves a Diels-Alder reaction of the terminal furan with a bismaleimide, followed by a Michael addition of a thiol on the mAb, generated by mild reduction of a disulfide bond in the hinge region. Polymer samples with a number average degree of polymerization of 35, with a binding capacity of 49.5 ± 6 Ln(3+) ions per chain, were loaded with 10 different types of Ln ions and conjugated to 10 different mAbs. A suite of metal-tagged Abs was tested by mass cytometry in a 10-plex single cell analysis of human adult peripheral blood, allowing us to quantify the antibody binding capacity of 10 different cell surface antigens associated with specific cell types.

77 FR 51751 - Information Collection Request; Farm Loan Programs, Direct Loan Making

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-27

... online instructions for submitting comments. Mail: Michael Moore, Senior Loan Officer, USDA, FSA, LMD... credit counseling, management advice, and financial guidance. Additionally, FSA must document that credit...

Discovery of 5-Amino- N -(1 H -pyrazol-4-yl)pyrazolo[1,5- a ]pyrimidine-3-carboxamide Inhibitors of IRAK4

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lim, Jongwon; Altman, Michael D.; Baker, James

2015-06-11

Interleukin-1 receptor associated kinase 4 (IRAK4) is an essential signal transducer downstream of the IL-1R and TLR superfamily, and selective inhibition of the kinase activity of the protein represents an attractive target for the treatment of inflammatory diseases. A series of 5-amino-N-(1H-pyrazol-4-yl)pyrazolo[1,5-a]pyrimidine-3-carboxamides was developed via sequential modifications to the 5-position of the pyrazolopyrimidine ring and the 3-position of the pyrazole ring. Replacement of substituents responsible for poor permeability and improvement of physical properties guided by cLogD led to the identification of IRAK4 inhibitors with excellent potency, kinase selectivity, and pharmacokinetic properties suitable for oral dosing.

A Parallel Saturation Algorithm on Shared Memory Architectures

NASA Technical Reports Server (NTRS)

Ezekiel, Jonathan; Siminiceanu

2007-01-01

Symbolic state-space generators are notoriously hard to parallelize. However, the Saturation algorithm implemented in the SMART verification tool differs from other sequential symbolic state-space generators in that it exploits the locality of ring events in asynchronous system models. This paper explores whether event locality can be utilized to efficiently parallelize Saturation on shared-memory architectures. Conceptually, we propose to parallelize the ring of events within a decision diagram node, which is technically realized via a thread pool. We discuss the challenges involved in our parallel design and conduct experimental studies on its prototypical implementation. On a dual-processor dual core PC, our studies show speed-ups for several example models, e.g., of up to 50% for a Kanban model, when compared to running our algorithm only on a single core.

Towards elucidation of the mechanism of biological nanomotors

NASA Astrophysics Data System (ADS)

Zhao, Zhengyi

Biological functions such as cell mitosis, bacterial binary fission, DNA replication or repair, homologous recombination, Holliday junction resolution, viral genome packaging, and cell entry all involve biomotor-driven DNA translocation. In the past, the ubiquitous biological nanomotors were classified into two categories: linear and rotation motors. In 2013, we discovered a third type of biomotor, revolving motor without rotation. The revolving motion is further found to be widespread among many biological systems. In addition, the detailed sequential action mechanism of the ATPase ring in the phi29 dsDNA packaging motor has been elucidated: ATP binding induces a conformational entropy alternation of ATPase to a high affinity toward dsDNA; ATP hydrolysis triggers another conformational entropy change in ATPase to a low DNA affinity, by which the dsDNA substrate is pushed toward an adjacent ATPase subunit. The subunit communication is regulated by an arginine finger that extends from one ATPase subunit to the adjacent unit, resulting in an asymmetrical hexameric organization. Continuation of this process promotes the movement and revolving of the dsDNA within the hexameric ATPase ring. Coordination of all the motor components facilitate the motion direction control of the viral DNA packaging motors, and make it unusually powerful and effective. KEYWORDS: Phi29 dsDNA Packaging Motor, Bio-nanomotor, RNA Nanotechnology, DNA Translocase, One-Way Revolving, ASCE Superfamily, AAA+ Superfamily.

Lithium formate ion clusters formation during electrospray ionization: Evidence of magic number clusters by mass spectrometry and ab initio calculations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shukla, Anil; Bogdanov, Bogdan

2015-02-14

Small cationic and anionic clusters of lithium formate were generated by electrospray ionization and their fragmentations were studied by tandem mass spectrometry. Singly as well as multiply charged clusters were formed with the general formulae, (HCOOLi)nLi+, (HCOOLi)nLimm+, (HCOOLi)nHCOO- and (HCOOLi)n(HCOO)mm-. Several magic number cluster ions were observed in both the positive and negative ion modes although more predominant in the positive ion mode with (HCOOLi)3Li+ being the most abundant and stable cluster ions. Fragmentations of singly charged clusters proceed first by the loss of a dimer unit ((HCOOLi)2) followed by sequential loss of monomer units (HCOOLi). In the case ofmore » positive cluster ions, all fragmentations lead to the magic cluster (HCOOLi)3Li+ at higher collision energies which later fragments to dimer and monomer ions in lower abundance. Quantum mechanical calculations performed for smaller cluster ions showed that the trimer ion has a closed ring structure similar to the phenalenylium structure with three closed rings connected to the lithium ion. Further additions of monomer units result in similar symmetric structures for hexamer and nonamer cluster ions. Thermochemical calculations show that trimer cluster ion is relatively more stable than neighboring cluster ions, supporting the experimental observation of a magic number cluster with enhanced stability.« less

Confirmation of a traveling feature in Saturn's rings in Cassini Imaging Science Subsystem data

NASA Astrophysics Data System (ADS)

Aye, K. M.; Rehnberg, M.; Esposito, L. W.

2017-12-01

Introduction: Using Cassini UVIS occultation data, a traveling wave feature has been identified in the Saturn rings that is most likely caused by the radial positions swap of the moons Janus and Epimetheus [1]. The hypothesis is that non-linear interferences between the density waves when being relocated by the moon swap create a solitary wave that is traveling outward through the rings. The observations in [1] further lead to the derivation of values for the radial travel speeds of the identified traveling features, from 39.6 km/yr for the Janus 5:4 resonance up to 45.8 for the Janus 4:3 resonance. Previous confirmations in ISS data: Work in [1] also identified the feature in Cassini Imaging Science Subsystem (ISS) data that was taken around the time of the UVIS occultations where the phenomenon was first discovered, so far one ISS image for each Janus resonances 2:1, 4:3, 5:4, and 6:5. Searches performed in ISS data: Filtering all existing ISS data down to the best resolutions that include both a clearly identifiable minimum and maximum ring radius, we have visually inspected approx. 200 images, both with and without known resonances within the image, but unbeknownst to the inspector. Identification of a feature of interest happens when train waves are being interrupted by anomalies. Comparing the radial locations of identified ISS features with those in UV data of [1], we have identified several at the same radii. Considering the vast differences in radial resolution, we conclude that the traveling feature causes observable anomalies at both small scales of meters, up to large scales of hundreds of meters to kilometers.References: [1] Rehnberg, M.E., Esposito, L.W., Brown, Z.L., Albers, N., Sremčević, M., Stewart, G.R., 2016. A Traveling Feature in Saturn's Rings. Icarus, accepted in June 2016. [2] K.-Michael Aye (2016, November 11). michaelaye/pyciss: . v0.6.0 Zenodo. https://doi.org/10.5281/zenodo.596802

Annular dynamics of memo3D annuloplasty ring evaluated by 3D transesophageal echocardiography.

PubMed

Nishi, Hiroyuki; Toda, Koichi; Miyagawa, Shigeru; Yoshikawa, Yasushi; Fukushima, Satsuki; Yoshioka, Daisuke; Sawa, Yoshiki

2018-04-01

We assessed the mitral annular motion after mitral valve repair with the Sorin Memo 3D® (Sorin Group Italia S.r.L., Saluggia, Italy), which is a unique complete semirigid annuloplasty ring intended to restore the systolic profile of the mitral annulus while adapting to the physiologic dynamism of the annulus, using transesophageal real-time three-dimensional echocardiography. 17 patients (12 male; mean age 60.4 ± 14.9 years) who underwent mitral annuloplasty using the Memo 3D ring were investigated. Mitral annular motion was assessed using QLAB®version8 allowing for a full evaluation of the mitral annulus dynamics. The mitral annular dimensions were measured throughout the cardiac cycle using 4D MV assessment2® while saddle shape was assessed through sequential measurements by RealView®. Saddle shape configuration of the mitral annulus and posterior and anterior leaflet motion could be observed during systole and diastole. The mitral annular area changed during the cardiac cycle by 5.7 ± 1.8%.The circumference length and diameter also changed throughout the cardiac cycle. The annular height was significantly higher in mid-systole than in mid-diastole (p < 0.05). The Memo 3D ring maintained a physiological saddle-shape configuration throughout the cardiac cycle. Real-time three-dimensional echocardiography analysis confirmed the motion and flexibility of the Memo 3D ring upon implantation.

A colorimetric detection of acrylamide in potato chips based on nucleophile-initiated thiol-ene Michael addition.

PubMed

Hu, Qinqin; Fu, Yingchun; Xu, Xiahong; Qiao, Zhaohui; Wang, Ronghui; Zhang, Ying; Li, Yanbin

2016-02-07

Acrylamide (AA), a neurotoxin and a potential carcinogen, has been found in various thermally processed foods such as potato chips, biscuits, and coffee. Simple, cost-effective, and sensitive methods for the rapid detection of AA are needed to ensure food safety. Herein, a novel colorimetric method was proposed for the visual detection of AA based on a nucleophile-initiated thiol-ene Michael addition reaction. Gold nanoparticles (AuNPs) were aggregated by glutathione (GSH) because of a ligand-replacement, accompanied by a color change from red to purple. In the presence of AA, after the thiol-ene Michael addition reaction between GSH and AA with the catalysis of a nucleophile, the sulfhydryl group of GSH was consumed by AA, which hindered the subsequent ligand-replacement and the aggregation of AuNPs. Therefore, the concentration of AA could be determined by the visible color change caused by dispersion/aggregation of AuNPs. This new method showed high sensitivity with a linear range from 0.1 μmol L(-1) to 80 μmol L(-1) and a detection limit of 28.6 nmol L(-1), and especially revealed better selectivity than the fluorescence sensing method reported previously. Moreover, this new method was used to detect AA in potato chips with a satisfactory result in comparison with the standard methods based on chromatography, which indicated that the colorimetric method can be expanded for the rapid detection of AA in thermally processed foods.

Optimization of the β-Elimination/Michael Addition Chemistry on Reversed-Phase Supports for Mass Spectrometry Analysis of O-Linked Protein Modifications

PubMed Central

Nika, Heinz; Nieves, Edward; Hawke, David H.; Angeletti, Ruth Hogue

2013-01-01

We previously adapted the β-elimination/Michael addition chemistry to solid-phase derivatization on reversed-phase supports, and demonstrated the utility of this reaction format to prepare phosphoseryl peptides in unfractionated protein digests for mass spectrometric identification and facile phosphorylation-site determination. Here, we have expanded the use of this technique to β-N-acetylglucosamine peptides, modified at serine/threonine, phosphothreonyl peptides, and phosphoseryl/phosphothreonyl peptides, followed in sequence by proline. The consecutive β-elimination with Michael addition was adapted to optimize the solid-phase reaction conditions for throughput and completeness of derivatization. The analyte remained intact during derivatization and was recovered efficiently from the silica-based, reversed-phase support with minimal sample loss. The general use of the solid-phase approach for enzymatic dephosphorylation was demonstrated with phosphoseryl and phosphothreonyl peptides and was used as an orthogonal method to confirm the identity of phosphopeptides in proteolytic mixtures. The solid-phase approach proved highly suitable to prepare substrates from low-level amounts of protein digests for phosphorylation-site determination by chemical-targeted proteolysis. The solid-phase protocol provides for a simple, robust, and efficient tool to prepare samples for phosphopeptide identification in MALDI mass maps of unfractionated protein digests, using standard equipment available in most biological laboratories. The use of a solid-phase analytical platform is expected to be readily expanded to prepare digest from O-glycosylated- and O-sulfonated proteins for mass spectrometry-based structural characterization. PMID:23997661

Facile construction of macroporous hybrid monoliths via thiol-methacrylate Michael addition click reaction for capillary liquid chromatography.

PubMed

Lin, Hui; Ou, Junjie; Liu, Zhongshan; Wang, Hongwei; Dong, Jing; Zou, Hanfa

2015-01-30

A facile approach based on thiol-methacrylate Michael addition click reaction was developed for construction of porous hybrid monolithic materials. Three hybrid monoliths were prepared via thiol-methacrylate click polymerization by using methacrylate-polyhedral oligomeric silsesquioxane (POSS) (cage mixture, n=8, 10, 12, POSS-MA) and three multi-thiol crosslinkers, 1,6-hexanedithiol (HDT), trimethylolpropane tris(3-mercaptopropionate) (TPTM) and pentaerythritol tetrakis(3-mercaptopropionate) (PTM), respectively, in the presence of porogenic solvents (n-propanol and PEG 200) and a catalyst (dimethylphenylphosphine, DMPP). The obtained monoliths possessed high thermal and chemical stabilities. Besides, they all exhibited high column efficiencies and excellent separation abilities in capillary liquid chromatography (cLC). The highest column efficiency could reach ca. 195,000N/m for butylbenzene on the monolith prepared with POSS-MA and TPTM (monolith POSS-TPTM) in reversed-phase (RP) mode at 0.64mm/s. Good chromatographic performance were all achieved in the separations of polycyclic aromatic hydrocarbons (PAHs), phenols, anilines, EPA 610 as well as bovine serum albumin (BSA) digest. The high column efficiencies in the range of 51,400-117,000N/m (achieved on the monolith POSS-PTM in RP mode) convincingly demonstrated the high separation abilities of these thiol-methacrylate based hybrid monoliths. All the results demonstrated the feasibility of the phosphines catalyzed thiol-methacrylate Michael addition click reaction in fabrication of monolithic columns with high efficiency for cLC applications. Copyright © 2014 Elsevier B.V. All rights reserved.

Michael Ulsh | NREL

Science.gov Websites

Michael Ulsh Photo of Michael Ulsh Michael Ulsh Manufacturing R&D Project Lead Michael.Ulsh -line quality control, the study of the performance and durability effects of manufacturing defects, and lead for a multi-lab consortium on solution processing and roll-to-roll manufacturing, and is involved

Pre-configured polyhedron based protection against multi-link failures in optical mesh networks.

PubMed

Huang, Shanguo; Guo, Bingli; Li, Xin; Zhang, Jie; Zhao, Yongli; Gu, Wanyi

2014-02-10

This paper focuses on random multi-link failures protection in optical mesh networks, instead of single, the dual or sequential failures of previous studies. Spare resource efficiency and failure robustness are major concerns in link protection strategy designing and a k-regular and k-edge connected structure is proved to be one of the optimal solutions for link protection network. Based on this, a novel pre-configured polyhedron based protection structure is proposed, and it could provide protection for both simultaneous and sequential random link failures with improved spare resource efficiency. Its performance is evaluated in terms of spare resource consumption, recovery rate and average recovery path length, as well as compared with ring based and subgraph protection under probabilistic link failure scenarios. Results show the proposed novel link protection approach has better performance than previous works.

Space Shuttle Projects

NASA Image and Video Library

1995-11-12

The STS-76 crew patch depicts the Space Shuttle Atlantis and Russia's Mir Space Station as the space ships prepare for a rendezvous and docking. The Spirit of 76, an era of new beginnings, is represented by the Space Shuttle rising through the circle of 13 stars in the Betsy Ross flag. STS-76 begins a new period of international cooperation in space exploration with the first Shuttle transport of a United States astronaut, Shannon W. Lucid, to the Mir Space Station for extended joint space research. Frontiers for future exploration are represented by stars and the planets. The three gold trails and the ring of stars in union form the astronaut logo. Two suited extravehicular activity (EVA) crew members in the outer ring represent the first EVA during Shuttle-Mir docked operations. The EVA objectives were to install science experiments on the Mir exterior and to develop procedures for future EVA's on the International Space Station. The surnames of the crew members encircle the patch: Kevin P. Chilton, mission commander; Richard A. Searfoss, pilot; Ronald M. Sega, Michael R. ( Rich) Clifford, Linda M. Godwin and Lucid, all mission specialists. This patch was designed by Brandon Clifford, age 12, and the crew members of STS-76.

Synthesis and stereochemical analysis of β-nitromethane substituted γ-amino acids and peptides.

PubMed

Ganesh Kumar, Mothukuri; Mali, Sachitanand M; Gopi, Hosahudya N

2013-02-07

The high diastereoselectivity in the Michael addition of nitromethane to α,β-unsaturated γ-amino esters, crystal conformations of β-nitromethane substituted γ-amino acids and peptides are studied. Results suggest that the N-Boc protected amide NH, conformations of α,β-unsaturated γ-amino esters and alkyl side chains play a crucial role in dictating the high diastereoselectivity of nitromethane addition to E-vinylogous amino esters. Investigation of the crystal conformations of both α,β-unsaturated γ-amino esters and the Michael addition products suggests that an H-C(γ)-C(β)=C(α) eclipsed conformer of the unsaturated amino ester leads to the major (anti) product compared to that of an N-C(γ)-C(β)=C(α) eclipsed conformer. The major diastereomers were separated and subjected to the peptide synthesis. The single crystal analysis of the dipeptide containing β-nitromethane substituted γ-amino acids reveals a helical type of folded conformation with an isolated H-bond involving a nine-atom pseudocycle.

Race, punishment, and the Michael Vick experience.

PubMed

Piquero, Alex R; Piquero, Nicole Leeper; Gertz, Marc; Baker, Thomas; Batton, Jason; Barnes, J C

2011-01-01

Objective. The relationship between race and crime has been contentious, focusing primarily on offending and incarceration patterns among minorities. There has been some limited work on public perceptions of criminal punishment, and findings show that while minorities believe in the role and rule of law, they simultaneously perceive the justice system as acting in a biased and/or unfair manner. Two limitations have stalled this literature. First, research has focused mainly on criminal punishments to the neglect of noncriminal punishments. Second, most studies have not examined whether race remains salient after considering other demographic variables or discrimination and legitimacy attitudes.Methods. Using data from 400 adults, we examine how race affects perceptions of criminal punishment and subsequent reinstatement into the National Football League in the case of Michael Vick, a star professional quarterback who pled guilty to charges of operating an illegal dog-fighting ring.Results. Findings show that whites are more likely to view Vick's punishment as too soft and that he should not be reinstated, while nonwhites had the opposite views. Race remained significant after controlling for other variables believed to be related to punishment perceptions.Conclusion. Attitudes toward both criminal punishment and NFL reinstatement vary across race such that there exists important divides in how individuals perceive the system meting out punishment and subsequently reintegrating offenders back into society. These results underscore that white and nonwhites perceive the law and its administration differently.

Additional Responses to Hugh Heclo's "On Thinking Institutionally"

ERIC Educational Resources Information Center

Lincoln, Timothy D.; Fennell, Robert C.

2011-01-01

Issue 13:3 of this journal (July 2010) included a "Conversation" on Hugh Heclo's recent publication "On Thinking Institutionally" (Paradigm Publishers, 2008) with a book review by Robert Fennell and responses by Richard Ascough, Tat-siong Benny Liew, Michael McLain, and Lynne Westfield. Here we publish two additional responses to this same book.…

Chiral phosphines in nucleophilic organocatalysis

PubMed Central

Xiao, Yumei; Sun, Zhanhu

2014-01-01

Summary This review discusses the tertiary phosphines possessing various chiral skeletons that have been used in asymmetric nucleophilic organocatalytic reactions, including annulations of allenes, alkynes, and Morita–Baylis–Hillman (MBH) acetates, carbonates, and ketenes with activated alkenes and imines, allylic substitutions of MBH acetates and carbonates, Michael additions, γ-umpolung additions, and acylations of alcohols. PMID:25246969

Design and synthesis of pH-sensitive polyamino-ester magneto-dendrimers: Surface functional groups effect on viability of human prostate carcinoma cell lines DU145.

PubMed

Dayyani, Nahid; Khoee, Sepideh; Ramazani, Ali

2015-06-15

Novel pH-sensitive, biocompatible and biodegradable magneto-dendrimers with OH and/or NH2 functional groups based on poly amino-ester were synthesized for delivery of anti-cancer drugs. Magnetite nanoparticles (MNPs) were synthesized by the co-precipitation method and their surfaces were modified by 3-aminopropyl triethoxysilane. The first and second generations of the magneto-dendrimer with hydroxyl end groups were produced by sequential acrylation and Michael addition reactions using the required amounts of acryloyl chloride and diethanolamine, respectively. The dendrimer containing amino functional surface groups up to second generation was synthesized by the same method using the necessary amounts of acryloyl chloride and ethylenediamine. These dendrimers were fully characterized by the Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), dynamic light scattering (DLS) and zeta potential analysis, vibrating-sample magnetometer (VSM), scanning electron microscope (SEM), transmission electron microscopy (TEM) and selected area electron diffraction (SAED). In-vitro release profiles of the drug-loaded magnetic nanoparticles and their cytotoxicity assay were investigated at two pHs (7.4 and 5.8). The hydrolytic degradation behavior of magneto-dendrimers was evaluated in PBS buffer. Our research suggests that magneto-dendrimers having amine or hydroxyl functional groups could be considered as the suitable nanocarriers for therapy applications. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Quantum switching of π-electron rotations in a nonplanar chiral molecule by using linearly polarized UV laser pulses.

PubMed

Mineo, Hirobumi; Yamaki, Masahiro; Teranishi, Yoshiaki; Hayashi, Michitoshi; Lin, Sheng Hsien; Fujimura, Yuichi

2012-09-05

Nonplanar chiral aromatic molecules are candidates for use as building blocks of multidimensional switching devices because the π electrons can generate ring currents with a variety of directions. We employed (P)-2,2'-biphenol because four patterns of π-electron rotations along the two phenol rings are possible and theoretically determine how quantum switching of the π-electron rotations can be realized. We found that each rotational pattern can be driven by a coherent excitation of two electronic states under two conditions: one is the symmetry of the electronic states and the other is their relative phase. On the basis of the results of quantum dynamics simulations, we propose a quantum control method for sequential switching among the four rotational patterns that can be performed by using ultrashort overlapped pump and dump pulses with properly selected relative phases and photon polarization directions. The results serve as a theoretical basis for the design of confined ultrafast switching of ring currents of nonplanar molecules and further current-induced magnetic fluxes of more sophisticated systems.

Coherent structures in interacting vortex rings

NASA Astrophysics Data System (ADS)

Deng, Jian; Xue, Jingyu; Mao, Xuerui; Caulfield, C. P.

2017-02-01

We investigate experimentally the nonlinear structures that develop from interacting vortex rings induced by a sinusoidally oscillating ellipsoidal disk in fluid at rest. We vary the scaled amplitude or Keulegan-Carpenter number 0.3

Transport properties of a quantum dot and a quantum ring in series

NASA Astrophysics Data System (ADS)

Seo, Minky; Chung, Yunchul

2018-01-01

The decoherence mechanism of an electron interferometer is studied by using a serial quantum dot and ring device. By coupling a quantum dot to a quantum ring (closed-loop electron interferometer), we were able to observe both Coulomb oscillations and Aharonov-Bohm interference simultaneously. The coupled device behaves like an ordinary double quantum dot at zero magnetic field while the conductance of the Coulomb blockade peak is modulated by the electron interference at finite magnetic fields. By injecting one electron at a time (by exploiting the sequential tunneling of a quantum dot) into the interferometer, we were able to study the visibility of the electron interference at non-zero bias voltage. The visibility was found to decay rapidly as the electron energy was increased, which was consistent with the recently reported result for an electron interferometer. However, the lobe pattern and the sudden phase jump became less prominent. These results imply that the lobe pattern and the phase jump in an electron interferometer may be due to electron interactions inside the interferometer, as is predicted by the theory.

KENNEDY SPACE CENTER, FLA. - STS-120 Mission Specialists Piers Sellers and Michael Foreman are in the Space Station Processing Facility for hardware familiarization. The mission will deliver the second of three Station connecting modules, Node 2, which attaches to the end of U.S. Lab. It will provide attach locations for the Japanese laboratory, European laboratory, the Centrifuge Accommodation Module and later Multi-Purpose Logistics Modules. The addition of Node 2 will complete the U.S. core of the International Space Station.

NASA Image and Video Library

2003-07-18

KENNEDY SPACE CENTER, FLA. - STS-120 Mission Specialists Piers Sellers and Michael Foreman are in the Space Station Processing Facility for hardware familiarization. The mission will deliver the second of three Station connecting modules, Node 2, which attaches to the end of U.S. Lab. It will provide attach locations for the Japanese laboratory, European laboratory, the Centrifuge Accommodation Module and later Multi-Purpose Logistics Modules. The addition of Node 2 will complete the U.S. core of the International Space Station.

Enzyme-catalyzed Michael addition for the synthesis of warfarin and its determination via fluorescence quenching of L-tryptophan

NASA Astrophysics Data System (ADS)

Yuan, Yusheng; Yang, Liu; Liu, Shaopu; Yang, Jidong; Zhang, Hui; Yan, Jingjing; Hu, Xiaoli

2017-04-01

A sensitive fluorescence sensor for warfarin was proposed via quenching the fluorescence of L-tryptophan due to the interaction between warfarin and L-tryptophan. Warfarin, as one of the most effective anticoagulants, was designed and synthesized via lipase from porcine pancreas (PPL) as a biocatalyst to catalyze the Michael addition of 4-hydroxycoumarin to α, β-unsaturated enones in organic medium in the presence of water. Furthermore, the spectrofluorometry was used to detect the concentration of warfarin with a linear range and detection limit (3σ/k) of 0.04-12.0 μmol L- 1 (R2 = 0.994) and 0.01 μmol L- 1, respectively. Herein, this was the first application of bio-catalytic synthesis and fluorescence for the determination of warfarin. The proposed method was applied to determine warfarin of the drug in tablets with satisfactory results.

Defect-mediated resonance shift of silicon-on-insulator racetrack resonators.

PubMed

Ackert, J J; Doylend, J K; Logan, D F; Jessop, P E; Vafaei, R; Chrostowski, L; Knights, A P

2011-06-20

We present a study on the effects of inert ion implantation of Silicon-On-Insulator (SOI) racetrack resonators. Selective ion implantation was used to create deep-level defects within a portion of the resonator. The resonant wavelength and round-trip loss were deduced for a range of sequential post-implantation annealing temperatures from 100 to 300 °C. As the devices were annealed there was a concomitant change in the resonance wavelength, consistent with an increase in refractive index following implantation and recovery toward the pre-implanted value. A total shift in resonance wavelength of ~2.9 nm was achieved, equivalent to a 0.02 increase in refractive index. The excess loss upon implantation increased to 301 dB/cm and was reduced to 35 dB/cm following thermal annealing. In addition to providing valuable data for those incorporating defects within resonant structures, we suggest that these results present a method for permanent tuning (or trimming) of ring resonator characteristics.

Unexpected regioselective carbon-hydrogen bond activation/cyclization of indolyl aldehydes or ketones with alkynes to benzo-fused oxindoles.

PubMed

Liu, Xingyan; Li, Gaocan; Song, Feijie; You, Jingsong

2014-09-25

Rhodium-catalyzed carbon-hydrogen bond activation has attracted great interest in the construction of carbon-carbon and carbon-heteroatom bonds. In recent years, transition metal-mediated oxygen transposition through a 'dehydration-rehydration' process has been considered as a promising strategy towards oxygen-functionalized compounds. Here we describe an unexpected rhodium-catalyzed regioselective carbon-hydrogen bond activation/cyclization of easily available indolyl aldehydes or ketones with alkynes to afford benzo-fused oxindoles, involving the sequential carbonyl-assisted carbon-hydrogen activation of the indole ring at the 4-position, [4+2] cyclization, aromatization via dehydration, nucleophilic addition of water to iminium and oxidation. Isotopic labelling experiments disclose the occurrence of apparent oxygen transposition via dehydration-rehydration from the indolyl-3-carbonyl group to the 2-position of pyrrole to forge a new carbonyl bond. The tandem reaction has been used as the key step for the concise synthesis of priolines, a type of alkaloid isolated from the roots of Salvia prionitis.

Additional diagnostic value of multiplane echocardiography over biplane imaging in assessment of mitral prosthetic valves.

PubMed Central

Faletra, F.; De Chiara, F.; Corno, R.; Passini, L.

1996-01-01

OBJECTIVE: To evaluate how often multiplane transoesophageal echocardiography yields new or complementary data in mitral prostheses in comparison with the exclusive use of biplane imaging. PATIENTS: 73 consecutive patients with mitral prostheses who underwent multiplane transoesophageal echocardiograpy between January 1993 and December 1994. METHODS: Biplane images (transverse and longitudinal planes) and multiplane images (transverse, longitudinal, and intermediate planes) were recorded on two separate videotapes. The data provided by multiplane transoesophageal echocardiography were evaluated as (a) new data (abnormalities missed by biplane imaging); (b) complementary data (better delineating lesions already visualised by biplane imaging); or (c) redundant data (data already provided by biplane imaging). RESULTS: Multiplane transoesophageal echocardiography revealed new abnormalities in seven patients (9.5%) (thrombi in three and paraprosthetic leaks in the remaining four) and complementary data in nine (12.3%). In patients with paraprosthetic regurgitation, the possibility of continuously visualising the sewing ring by means of sequential angulations allowed the circumferential extension of the leak to be measured. In seven patients with paravalvar regurgitation who underwent surgery, the extension of the leak as measured by the multiplane approach closely corresponded with the surgical data. CONCLUSIONS: In comparison with the exclusive use of biplane imaging, the multiplane approach added new or complementary data in a significant proportion of patients with mitral prostheses. The ability to obtain the sequential adjacent planes allowed a more reliable appraisal of the extension of the leak and other abnormalities. Images PMID:8697166

Combining Orthogonal Chain-End Deprotections and Thiol-Maleimide Michael Coupling: Engineering Discrete Oligomers by an Iterative Growth Strategy.

PubMed

Huang, Zhihao; Zhao, Junfei; Wang, Zimu; Meng, Fanying; Ding, Kunshan; Pan, Xiangqiang; Zhou, Nianchen; Li, Xiaopeng; Zhang, Zhengbiao; Zhu, Xiulin

2017-10-23

Orthogonal maleimide and thiol deprotections were combined with thiol-maleimide coupling to synthesize discrete oligomers/macromolecules on a gram scale with molecular weights up to 27.4 kDa (128mer, 7.9 g) using an iterative exponential growth strategy with a degree of polymerization (DP) of 2 n -1. Using the same chemistry, a "readable" sequence-defined oligomer and a discrete cyclic topology were also created. Furthermore, uniform dendrons were fabricated using sequential growth (DP=2 n -1) or double exponential dendrimer growth approaches (DP=22n -1) with significantly accelerated growth rates. A versatile, efficient, and metal-free method for construction of discrete oligomers with tailored structures and a high growth rate would greatly facilitate research into the structure-property relationships of sophisticated polymeric materials. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Diverse high-torque bacterial flagellar motors assemble wider stator rings using a conserved protein scaffold

PubMed Central

Ribardo, Deborah A.; Brennan, Caitlin A.; Ruby, Edward G.; Jensen, Grant J.; Hendrixson, David R.

2016-01-01

Although it is known that diverse bacterial flagellar motors produce different torques, the mechanism underlying torque variation is unknown. To understand this difference better, we combined genetic analyses with electron cryo-tomography subtomogram averaging to determine in situ structures of flagellar motors that produce different torques, from Campylobacter and Vibrio species. For the first time, to our knowledge, our results unambiguously locate the torque-generating stator complexes and show that diverse high-torque motors use variants of an ancestrally related family of structures to scaffold incorporation of additional stator complexes at wider radii from the axial driveshaft than in the model enteric motor. We identify the protein components of these additional scaffold structures and elucidate their sequential assembly, demonstrating that they are required for stator-complex incorporation. These proteins are widespread, suggesting that different bacteria have tailored torques to specific environments by scaffolding alternative stator placement and number. Our results quantitatively account for different motor torques, complete the assignment of the locations of the major flagellar components, and provide crucial constraints for understanding mechanisms of torque generation and the evolution of multiprotein complexes. PMID:26976588

Photoinitiator-Free Synthesis of Endothelial Cell Adhesive and Enzymatically Degradable Hydrogels

PubMed Central

Jones, Derek R.; Marchant, Roger E.; von Recum, Horst; Gupta, Anirban Sen; Kottke-Marchant, Kandice

2015-01-01

We report on a photoinitiator-free synthetic method of incorporating bioactivity into poly(ethylene glycol) (PEG) hydrogels in order to control physical properties, enzymatic biodegradability and cell-specific adhesiveness of the polymer network, while eliminating the need for UV-mediated photopolymerization. To accomplish this, hydrogel networks were polymerized using Michael addition with four-arm PEG acrylate (10 kDa), using a collagenase sensitive peptide (CSP) as a crosslinker, and introducing an endothelial cell adhesive peptide either terminally (RGD) or attached to the crosslinking peptide sequence (CSP-RGD). The efficiency of the Michael addition reactions were determined by NMR and Ellman’s assay. Successful decoupling of cell adhesivity and physical properties was demonstrated by quantifying and comparing the swelling ratios and Young’s Moduli of various hydrogel formulations. Degradation profiles were established by incubating functionalized hydrogels in collagenase solutions (0.0 – 1.0 µg/mL), demonstrating that functionalized hydrogels degraded at a rate dependent upon collagenase concentration. Moreover, it was shown that the degradation rate was independent of CSP-RGD concentration. Cell attachment and proliferation on functionalized hydrogels were compared for various RGD concentrations, providing evidence that cell attachment and proliferation were directly related to relative amounts of the CSP-RGD combination peptide. An increase in cell viability was achieved using Michael addition techniques when compared to UV-polymerization, and was assessed by a LIVE/DEAD fluorescence assay. This photoinitiator-free method shows promise in creating hydrogel-based tissue engineering scaffolds allow for decoupled cell adhesivity and physical properties and that render greater cell viability. PMID:25462848

The effects of the sequential addition of synthesis parameters on the performance of alkali activated fly ash mortar

NASA Astrophysics Data System (ADS)

Dassekpo, Jean-Baptiste Mawulé; Zha, Xiaoxiong; Zhan, Jiapeng; Ning, Jiaqian

Geopolymer is an energy efficient and sustainable material that is currently used in construction industry as an alternative for Portland cement. As a new material, specific mix design method is essential and efforts have been made to develop a mix design procedure with the main focus on achieving better compressive strength and economy. In this paper, a sequential addition of synthesis parameters such as fly ash-sand, alkaline liquids, plasticizer and additional water at well-defined time intervals was investigated. A total of 4 mix procedures were used to study the compressive performance on fly ash-based geopolymer mortar and the results of each method were analyzed and discussed. Experimental results show that the sequential addition of sodium hydroxide (NaOH), sodium silicate (Na2SiO3), plasticizer (PL), followed by adding water (WA) increases considerably the compressive strengths of the geopolymer-based mortar. These results clearly demonstrate the high significant influence of sequential addition of synthesis parameters on geopolymer materials compressive properties, and also provide a new mixing method for the preparation of geopolymer paste, mortar and concrete.

Early alterations in vascular contractility associated to changes in fatty acid composition and oxidative stress markers in perivascular adipose tissue.

PubMed

Rebolledo, Alejandro; Rebolledo, Oscar R; Marra, Carlos A; García, María E; Roldán Palomo, Ana R; Rimorini, Laura; Gagliardino, Juan J

2010-10-21

To test the early effect of fructose-induced changes in fatty acid composition and oxidative stress markers in perivascular adipose tissue (PVAT) upon vascular contractility. Adult male Wistar rats were fed a commercial diet without (CD) or with 10% fructose (FRD) in the drinking water for 3 weeks. We measured plasma metabolic parameters, lipid composition and oxidative stress markers in aortic PVAT. Vascular contractility was measured in aortic rings sequentially, stimulated with serotonin (5-HT) and high K+-induced depolarization using intact and thereafter PVAT-deprived rings. Comparable body weights were recorded in both groups. FRD rats had increased plasma triglyceride and fructosamine levels. Their PVAT had an increased saturated to mono- or poly-unsaturated fatty acid ratio, a significant decrease in total superoxide dismutase and glutathione peroxidase activities and in the total content of glutathione. Conversely, lipid peroxidation (TBARS), nitric oxide content, and gluthathione reductase activity were significantly higher, indicating an increase in oxidative stress. In aortic rings, removal of PVAT increased serotonin-induced contractions, but the effect was significantly lower in rings from FRD rats. This effect was no longer observed when the two contractions were performed in PVAT-deprived rings. PVAT did not affect the contractions triggered by high K+-induced depolarization either in CD or FRD rats. FRD induces multiple metabolic and endocrine systemic alterations which also alter PVAT and the vascular relaxant properties of this tissue. The changes in PVAT would affect its paracrine modulation of vascular function.

[Development of boomerang-type intramolecular cascade reactions and application to natural product synthesis].

PubMed

Takasu, K

2001-12-01

Intramolecular cascade reaction has received much attention as a powerful methodology to construct a polycyclic framework in organic synthesis. We have been developing "boomerang-type cascade reaction" to construct a variety of polycyclic skeletons efficiently. In the above reactions, a nucleophilic function of substrates changes the character into an electrophile after the initial reaction, and the electrophilic group acts as a nucleophile in the second reaction. That is, the reaction center stepwise moves from one functional group back to the same one via other functional groups. The stream of the electron concerning the cascade reaction is like a locus of boomerang. We show here three different boomerang-type reactions via ionic species or free radicals. 1) Diastereoselective Michael-aldol reaction based on the chiral auxiliary method and enantioselective Michael-aldol reaction by the use of external chiral sources. 2) Short and efficient total syntheses of longifolane sesquiterpenes utilizing intramolecular double Michael addition as a key step. 3) Development of boomerang-type radical cascade reaction of halopolyenes to construct terpenoid skeletons and its regioselectivity.

Enantioselective conjugate additions of α-amino radicals via cooperative photoredox and Lewis acid catalysis.

PubMed

Ruiz Espelt, Laura; McPherson, Iain S; Wiensch, Eric M; Yoon, Tehshik P

2015-02-25

We report the highly enantioselective addition of photogenerated α-amino radicals to Michael acceptors. This method features a dual-catalyst protocol that combines transition metal photoredox catalysis with chiral Lewis acid catalysis. The combination of these two powerful modes of catalysis provides an effective, general strategy to generate and control the reactivity of photogenerated reactive intermediates.

[Determination of cadmium by HG-aFS in soil of virescent zone in Chengdu city].

PubMed

Chen, Yuan; Zeng, Ying; Wu, Hong-ji; Wang, Qin-er

2008-12-01

The different speciations of cadmium in soil samples from Chengdu greenbelt were extracted by Tessier sequential extraction method. The contents of total cadmium and different speciation cadmium were determined using HG-AFS. Under optimization condition of HG-AFS and using 2% HCl as medium, and 30 g x L(-1) KBH4 as reductive reagent, 1 mg x L(-1) Co2+ acting together with 10 g x L(-1) CH4N2S can advance the generating efficiency of cadmium compound. The effects of the coexisting elements in soil on the determination of cadmium can be reduced if certain amount of Na4P2O7, K2SO4 and BaCl2 are added. The linear range is 0-10 mg x L(-1) with r=0.9991 and the detection limit is 0.016 mg x L(-1). The recovery is 97.80%-100.2% with RSD of 1.93%. The analytical method is very sensitive and accurate. The distribution of average percentage of five speciations of cadmium in experimental soil samples is: residual fraction (62.1%) > exchangeable fraction (11.7%) > Fe-Mn oxide-bound (9.71%) > carbonate-bound (4.17%) > organic-bound (3.47%). Although residual fraction is the main speciation of cadmium in soil, the content of exchangeable fraction is relatively high. Thus the bioactivity of cadmium in the research area should be recognized. The concentration of cadmium exceeds the country standard in 19 soil sample, accounting for 86. 4% of all soil samples. The soil from Chengdu greenbelt located in 1st ring road, 2nd ring road and 3rd ring road was polluted to different degree. The relative pollution magnitude of them is: 2nd ring road > 1st ring road > 3rd ring road.

Camphor revisited: involvement of a unique monooxygenase in metabolism of 2-oxo-delta 3-4,5,5-trimethylcyclopentenylacetic acid by Pseudomonas putida.

PubMed Central

Ougham, H J; Taylor, D G; Trudgill, P W

1983-01-01

Previously, Pseudomonas putida was shown to degrade (+)-camphor, and cleavage of the first ring of the bicyclic structure involved two monooxygenases (a hydroxylase and a ring oxygen-inserting enzyme), a dehydrogenase, and spontaneous cleavage of an unstable oxygenation product (lactone). Cleavage of the second ring was not demonstrated but was assumed also to occur by ring oxygen insertion, since the predicted oxygenation product was extracted from whole-cell incubation systems. Our investigation established that metabolism of the first ring cleavage intermediate, 2-oxo-delta 3-4,5,5-trimethylcyclopentenylacetic acid, occurred through the sequential action of two inducible enzymes, a coenzyme A ester synthetase and an oxygenase. The oxygenase was purified to homogeneity and had a molecular weight of 106,000. This enzyme carried a single molecule of flavin adenine dinucleotide and consisted of two identical subunits. Iron was not present at a significant level. The oxygenase was specific for NADPH as the electron donor and absolutely specific for the coenzyme A ester of 2-oxo-delta 3-4,5,5-trimethylcyclopentenylacetic acid as the substrate. The reaction stoichiometry was compatible with this enzyme being a monooxygenase, and a mass spectral analysis of the methyl ester of the product confirmed the insertion of a single oxygen atom. The enzyme appeared to be analogous to, although distinct from. 2,5-diketocamphane 1,2-monooxygenase in catalyzing a "biological Baeyer-Villiger" reaction with the formation of a lactone. Structural analogy suggested that this lactone, like the first, was also unstable and susceptible to spontaneous ring opening, although this was not experimentally established. Images PMID:6848481

Camphor revisited: involvement of a unique monooxygenase in metabolism of 2-oxo-delta 3-4,5,5-trimethylcyclopentenylacetic acid by Pseudomonas putida.

PubMed

Ougham, H J; Taylor, D G; Trudgill, P W

1983-01-01

Previously, Pseudomonas putida was shown to degrade (+)-camphor, and cleavage of the first ring of the bicyclic structure involved two monooxygenases (a hydroxylase and a ring oxygen-inserting enzyme), a dehydrogenase, and spontaneous cleavage of an unstable oxygenation product (lactone). Cleavage of the second ring was not demonstrated but was assumed also to occur by ring oxygen insertion, since the predicted oxygenation product was extracted from whole-cell incubation systems. Our investigation established that metabolism of the first ring cleavage intermediate, 2-oxo-delta 3-4,5,5-trimethylcyclopentenylacetic acid, occurred through the sequential action of two inducible enzymes, a coenzyme A ester synthetase and an oxygenase. The oxygenase was purified to homogeneity and had a molecular weight of 106,000. This enzyme carried a single molecule of flavin adenine dinucleotide and consisted of two identical subunits. Iron was not present at a significant level. The oxygenase was specific for NADPH as the electron donor and absolutely specific for the coenzyme A ester of 2-oxo-delta 3-4,5,5-trimethylcyclopentenylacetic acid as the substrate. The reaction stoichiometry was compatible with this enzyme being a monooxygenase, and a mass spectral analysis of the methyl ester of the product confirmed the insertion of a single oxygen atom. The enzyme appeared to be analogous to, although distinct from. 2,5-diketocamphane 1,2-monooxygenase in catalyzing a "biological Baeyer-Villiger" reaction with the formation of a lactone. Structural analogy suggested that this lactone, like the first, was also unstable and susceptible to spontaneous ring opening, although this was not experimentally established.

KSC-08pd2572

NASA Image and Video Library

2008-09-05

CAPE CANAVERAL, Fla. – In the Payload Hazardous Servicing Facility at NASA’s Kennedy Space Center, crew members with the STS-125 mission get a close look at some of the equipment associated with their mission to service NASA’s Hubble Space Telescope. Looking at the Soft Capture Mechanism on the Flight Support Structure are a technician (pointing) and Mission Specialists Mike Massimino and Michael Good. The mechanism will enable the future rendezvous, capture and safe disposal of NASA's Hubble Space Telescope by either a crewed or robotic mission. The ring-like device attaches to Hubble’s aft bulkhead. The STS-125 crew is taking part in a crew equipment interface test, which provides experience handling tools, equipment and hardware they will use on their mission. Space shuttle Atlantis is targeted to launch on the STS-125 mission Oct. 10. Photo credit: NASA/Kim Shiflett

KSC-08pd2574

NASA Image and Video Library

2008-09-05

CAPE CANAVERAL, Fla. – In the Payload Hazardous Servicing Facility at NASA’s Kennedy Space Center, crew members with the STS-125 mission get a close look at some of the equipment associated with their mission to service NASA’s Hubble Space Telescope. Mission Specialist Michael Good points out part of the Flight Support Structure to Mission Specialist Andrew Feustel, right. The Soft Capture Mechanism is above him. The mechanism will enable the future rendezvous, capture and safe disposal of NASA's Hubble Space Telescope by either a crewed or robotic mission. The ring-like device attaches to Hubble’s aft bulkhead. The STS-125 crew is taking part in a crew equipment interface test, which provides experience handling tools, equipment and hardware they will use on their mission. Space shuttle Atlantis is targeted to launch on the STS-125 mission Oct. 10. Photo credit: NASA/Kim Shiflett

Nuclear valve manufacturer selects stainless forgings

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

1976-02-01

Forged type 316 stainless steel components for nuclear valves are described. Automatic plasma arc welding with powder filler alloys is employed for hardfacing. Seat ring forgings are surfaced four-at-a-time with Stellite No. 156 in a sequential manner to minimize heat input to the individual components. After cladding and machining, seat rings are welded into the valve body using a semiautomatic, hot-wire gas tungsten-arc process. Disc faces and guide slots are surfaced with Stellite No. 6. The valve stem is machined from 17-4PH forged bar stock in the H-1100 condition. The heat treatment is specified to minimize pitting under prolonged exposuremore » to wet packing. A 12 rms (0.3 $mu$m) surface finish minimizes tearing of the packing and subsequent leakage. The link and stem pin are SA 564 Grade 660 (in the H-1100 condition) and ASTM A637 Grade 718 respectively. (JRD)« less

76 FR 55904 - Michael J. Donahue; Notice of Termination of Exemption By Implied Surrender and Soliciting...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-09

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Project No. 6649-008] Michael J.... Date Initiated: September 1, 2011. d. Exemptee: Michael J. Donahue. e. Name and Location of Project.... Initiated Pursuant to: 18 CFR 4.106. g. Exemptee Contact Information: Mr. Michael J. Donahue, Route 3, Box...

76 FR 58264 - Michael J. Donahue; Notice of Termination of Exemption by Implied Surrender and Soliciting...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-20

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Project No. 6649-008] Michael J.... Date Initiated: September 13, 2011. d. Exemptee: Michael J. Donahue. e. Name and Location of Project.... Initiated Pursuant to: 18 CFR 4.106. g. Exemptee Contact Information: Mr. Michael J. Donahue, Route 3, Box...

75 FR 62635 - Proposed Information Collection (Patient Satisfaction Survey Michael E. DeBakey Home Care Program...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-12

... Collection (Patient Satisfaction Survey Michael E. DeBakey Home Care Program) Activity: Comment Request... determine patients' satisfaction with services provided by or through the Michael E. DeBakey Home Care...: Patient Satisfaction Survey Michael E. DeBakey Home Care Program, VA Form 10-0476. OMB Control Number...

77 FR 69550 - Proposed Information Collection (Patient Satisfaction Survey Michael E. DeBakey Home Care Program...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-11-19

... (Patient Satisfaction Survey Michael E. DeBakey Home Care Program) Activity: Comment Request AGENCY... information needed to determine patients' satisfaction with services provided by or through the Michael E...: Patient Satisfaction Survey Michael E. DeBakey Home Care Program, VA Form 10-0476. OMB Control Number...

Fan in the F Ring

NASA Image and Video Library

2010-07-20

This mosaic of images from NASA Cassini spacecraft depicts fan-like structures in Saturn tenuous F ring. Bright features are also visible near the core of the ring. Such features suggest the existence of additional objects in the F ring.

F Ring Bright Core Clumps

NASA Image and Video Library

2010-07-20

Bright clumps of ring material and a fan-like structure appear near the core of Saturn tenuous F ring in this mosaic of images from NASA Cassini spacecraft. Such features suggest the existence of additional objects in the F ring.

77 FR 14041 - Major Portion Prices and Due Date for Additional Royalty Payments on Indian Gas Production in...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-08

...) 231-3473; email [email protected] ; or Mike Curry, Team B, Western Audit and Compliance, ONRR; telephone (303) 231-3741; fax (303) 231- 3473; email Michael.Curry@onrr.gov . Mailing address: Office of...

Vertical axis wind turbines

DOEpatents

Krivcov, Vladimir [Miass, RU; Krivospitski, Vladimir [Miass, RU; Maksimov, Vasili [Miass, RU; Halstead, Richard [Rohnert Park, CA; Grahov, Jurij [Miass, RU

2011-03-08

A vertical axis wind turbine is described. The wind turbine can include a top ring, a middle ring and a lower ring, wherein a plurality of vertical airfoils are disposed between the rings. For example, three vertical airfoils can be attached between the upper ring and the middle ring. In addition, three more vertical airfoils can be attached between the lower ring and the middle ring. When wind contacts the vertically arranged airfoils the rings begin to spin. By connecting the rings to a center pole which spins an alternator, electricity can be generated from wind.

An approach to develop an algorithm to detect the climbing height in radial-axial ring rolling

NASA Astrophysics Data System (ADS)

Husmann, Simon; Hohmann, Magnus; Kuhlenkötter, Bernd

2017-10-01

Radial-axial ring rolling is the mainly used forming process to produce seamless rings, which are applied in miscellaneous industries like the energy sector, the aerospace technology or in the automotive industry. Due to the simultaneously forming in two opposite rolling gaps and the fact that ring rolling is a mass forming process, different errors could occur during the rolling process. Ring climbing is one of the most occurring process errors leading to a distortion of the ring's cross section and a deformation of the rings geometry. The conventional sensors of a radial-axial rolling machine could not detect this error. Therefore, it is a common strategy to roll a slightly bigger ring, so that random occurring process errors could be reduce afterwards by removing the additional material. The LPS installed an image processing system to the radial rolling gap of their ring rolling machine to enable the recognition and measurement of climbing rings and by this, to reduce the additional material. This paper presents the algorithm which enables the image processing system to detect the error of a climbing ring and ensures comparable reliable results for the measurement of the climbing height of the rings.

A fast and accurate online sequential learning algorithm for feedforward networks.

PubMed

Liang, Nan-Ying; Huang, Guang-Bin; Saratchandran, P; Sundararajan, N

2006-11-01

In this paper, we develop an online sequential learning algorithm for single hidden layer feedforward networks (SLFNs) with additive or radial basis function (RBF) hidden nodes in a unified framework. The algorithm is referred to as online sequential extreme learning machine (OS-ELM) and can learn data one-by-one or chunk-by-chunk (a block of data) with fixed or varying chunk size. The activation functions for additive nodes in OS-ELM can be any bounded nonconstant piecewise continuous functions and the activation functions for RBF nodes can be any integrable piecewise continuous functions. In OS-ELM, the parameters of hidden nodes (the input weights and biases of additive nodes or the centers and impact factors of RBF nodes) are randomly selected and the output weights are analytically determined based on the sequentially arriving data. The algorithm uses the ideas of ELM of Huang et al. developed for batch learning which has been shown to be extremely fast with generalization performance better than other batch training methods. Apart from selecting the number of hidden nodes, no other control parameters have to be manually chosen. Detailed performance comparison of OS-ELM is done with other popular sequential learning algorithms on benchmark problems drawn from the regression, classification and time series prediction areas. The results show that the OS-ELM is faster than the other sequential algorithms and produces better generalization performance.

Rings Research in the Next Decade

NASA Astrophysics Data System (ADS)

Burns, J. A.; Tiscareno, M. S.

2009-12-01

The study of planetary ring systems forms a key component of planetary science for several reasons: 1) The evolution and current states of planets and their satellites are affected in many ways by rings, while 2) conversely, properties of planets and moons and other solar system populations are revealed by their effects on rings; 3) highly structured and apparently delicate ring systems may be bellwethers, constraining various theories of the origin and evolution of their entire planetary system; and finally, 4) planetary rings provide an easily observable analogue to other astrophysical disk systems, enabling real “ground truth” results applicable to disks much more remote in space and/or time, including proto-planetary disks, circum-stellar disks, and even galaxies. Significant advances have been made in rings science in the past decade. The highest-priority rings research recommendations of the last Planetary Science Decadal Survey were to operate and extend the Cassini orbiter mission at Saturn; this has been done with tremendous success, accounting for much of the progress made on key science questions, as we will describe. Important progress in understanding the rings of Saturn and other planets has also come from Earth-based observational and theoretical work, again as prioritized by the last Decadal Survey. However, much important work remains to be done. At Saturn, the Cassini Solstice Mission must be brought to a successful completion. Priority should also be placed on sending spacecraft to Neptune and/or Uranus, now unvisited for more than 20 years. At Jupiter and Pluto, opportunities afforded by visiting spacecraft capable of studying rings should be exploited. On Earth, the need for continued research and analysis remains strong, including in-depth analysis of rings data already obtained, numerical and theoretical modeling work, laboratory analysis of materials and processes analogous to those found in the outer solar system, and continued Earth-based observations. Members of the Rings White Paper Team include: Matthew S. Tiscareno (Cornell U), Nicole Albers (U of Colorado), Todd Bradley (U of Central Florida), André Brahic (U of Paris, France), Shawn Brooks (JPL), Joseph Burns (Cornell U), Carlos Chavez (UNAM, Mexico), Joshua Colwell (U of Central Florida), Jeff Cuzzi (NASA Ames), Imke de Pater (U of California), Luke Dones (SwRI), Richard Durisen (Indiana U), Michael Evans (Cornell U), Cecile Ferrari (CEA Saclay, France), Gianrico Filacchione (INAF-IASF, Italy), Silvia Giuliatti Winter (UNESP, Brazil), Mitch Gordon (SETI), Amara Graps (SwRI), Eberhard Gruen (MPI, Germany), Douglas Hamilton (U of Maryland), Matthew Hedman (Cornell U), Mihaly Horanyi (U of Colorado), Sascha Kempf (MPI, Germany), Harald Krueger (MPI, Germany), Steve Larson (U of Arizona), Mark Lewis (Trinity U), Jack Lissauer (NASA Ames), Colin Mitchell (CICLOPS/SSI), Carl Murray (QMUL, England), Philip Nicholson (Cornell U), Cathy Olkin (SwRI), Robert Pappalardo (JPL), Frank Postberg (MPI, Germany), Heikki Salo (U of Oulu, Finland), Juergen Schmidt (U of Potsdam, Germany), David Seal (JPL), Mark Showalter (SETI), Frank Spahn (U of Potsdam, Germany), Linda Spilker (JPL), Joseph Spitale (CICLOPS/SSI), Ralf Srama (MPI, Germany), Miodrag Sremcevic (U of Colorado), Glen Stewart (U of Colorado), John Weiss (Carleton College), Padma Yanamandra-Fisher (JPL)

Maniac Talk - Michael Mishchenko

NASA Image and Video Library

2015-01-26

Michael Mishchenko Maniac Lecture, January 26, 2015 NASA climate scientist Dr. Michael I. Mishchenko presented a Maniac Talk entitled "How much first-principle physics do we need in remote-sensing and atmospheric-radiation research." Michael explained his skepticism and how it has shaped his contributions to the disciplines of electromagnetic scattering, radiative transfer, and remote sensing, which have found widespread use.

Multiuser signal detection using sequential decoding

NASA Astrophysics Data System (ADS)

Xie, Zhenhua; Rushforth, Craig K.; Short, Robert T.

1990-05-01

The application of sequential decoding to the detection of data transmitted over the additive white Gaussian noise channel by K asynchronous transmitters using direct-sequence spread-spectrum multiple access is considered. A modification of Fano's (1963) sequential-decoding metric, allowing the messages from a given user to be safely decoded if its Eb/N0 exceeds -1.6 dB, is presented. Computer simulation is used to evaluate the performance of a sequential decoder that uses this metric in conjunction with the stack algorithm. In many circumstances, the sequential decoder achieves results comparable to those obtained using the much more complicated optimal receiver.

Searching for a traveling feature in Saturn's rings in Cassini Imaging Science Subsystem data

NASA Astrophysics Data System (ADS)

Aye, Klaus-Michael; Rehnberg, Morgan; Brown, Zarah; Esposito, Larry W.

2016-10-01

Introduction: Using Cassini UVIS occultation data, a traveling wave feature has been identified in the Saturn rings that is most likely caused by the radial positions swap of the moons Janus and Epimetheus [1]. The hypothesis is that non-linear interferences between the linear density waves when being relocated by the moon swap create a solitary wave that is traveling outward through the rings. The observations in [1] further lead to the derivation of values for the radial travel speeds of the identified traveling features, from 39.6 km/yr for the Janus 5:4 resonance up to 45.8 for the Janus 4:3 resonance.Previous confirmations in ISS data: Work in [1] also identified the feature in Cassini Imaging Science Subsystem (ISS) data that was taken around the time of the UVIS occultations where the phenomenon was first discovered, so far one ISS image for each Janus resonances 2:1, 4:3, 5:4, and 6:5.Search guided by predicted locations: Using the observation-fitted radial velocities from [1], we can extrapolate these to identify Saturn radii at which the traveling feature should be found at later times. Using this and new image analysis and plotting tools available in [2], we have identified a potential candidate feature in an ISS image that was taken 2.5 years after the feature causing moon swap in January 2006. We intend to expand our search by identifying candidate ISS data by a meta-database search constraining the radius at future times corresponding to the predicted future locations of the hypothesized solitary wave and present our findings at this conference.References: [1] Rehnberg, M.E., Esposito, L.W., Brown, Z.L., Albers, N., Sremčević, M., Stewart, G.R., 2016. A Traveling Feature in Saturn's Rings. Icarus, accepted in June 2016. [2] K.-Michael Aye. (2016). pyciss: v0.5.0. Zenodo. 10.5281/zenodo.53092

Early alterations in vascular contractility associated to changes in fatty acid composition and oxidative stress markers in perivascular adipose tissue

PubMed Central

2010-01-01

Aim To test the early effect of fructose-induced changes in fatty acid composition and oxidative stress markers in perivascular adipose tissue (PVAT) upon vascular contractility. Methods Adult male Wistar rats were fed a commercial diet without (CD) or with 10% fructose (FRD) in the drinking water for 3 weeks. We measured plasma metabolic parameters, lipid composition and oxidative stress markers in aortic PVAT. Vascular contractility was measured in aortic rings sequentially, stimulated with serotonin (5-HT) and high K+-induced depolarization using intact and thereafter PVAT-deprived rings. Results Comparable body weights were recorded in both groups. FRD rats had increased plasma triglyceride and fructosamine levels. Their PVAT had an increased saturated to mono- or poly-unsaturated fatty acid ratio, a significant decrease in total superoxide dismutase and glutathione peroxidase activities and in the total content of glutathione. Conversely, lipid peroxidation (TBARS), nitric oxide content, and gluthathione reductase activity were significantly higher, indicating an increase in oxidative stress. In aortic rings, removal of PVAT increased serotonin-induced contractions, but the effect was significantly lower in rings from FRD rats. This effect was no longer observed when the two contractions were performed in PVAT-deprived rings. PVAT did not affect the contractions triggered by high K+-induced depolarization either in CD or FRD rats. Conclusions FRD induces multiple metabolic and endocrine systemic alterations which also alter PVAT and the vascular relaxant properties of this tissue. The changes in PVAT would affect its paracrine modulation of vascular function. PMID:20964827

Redox shuttles having an aromatic ring fused to a 1,1,4,4-tetrasubstituted cyclohexane ring

DOEpatents

Weng, Wei; Zhang, Zhengcheng; Amine, Khalil

2015-12-01

An electrolyte includes an alkali metal salt; an aprotic solvent; and a redox shuttle additive including an aromatic compound having at least one aromatic ring fused with at least one non-aromatic ring, the aromatic ring having two or more oxygen or phosphorus-containing substituents.

Reaction Mechanism of Covalent Modification of Phosphatidylethanolamine Lipids by Reactive Aldehydes 4-Hydroxy-2-nonenal and 4-Oxo-2-nonenal.

PubMed

Vazdar, Katarina; Vojta, Danijela; Margetić, Davor; Vazdar, Mario

2017-03-20

4-Hydroxy-2-nonenal (HNE) and 4-oxo-2-nonenal (ONE) are biologically important reactive aldehydes formed during oxidative stress in phospholipid bilayers. They are highly reactive species due to presence of several reaction centers and can react with amino acids in peptides and proteins, as well as phosphoethanolamine (PE) lipids, thus modifying their biological activity. The aim of this work is to study in a molecular detail the reactivity of HNE and ONE toward PE lipids in a simplified system containing only lipids and reactive aldehydes in dichloromethane as an inert solvent. We use a combination of quantum chemical calculations, 1 H NMR measurements, FT-IR spectroscopy, and mass spectrometry experiments and show that for both reactive aldehydes two types of chemical reactions are possible: formation of Michael adducts and Schiff bases. In the case of HNE, an initially formed Michael adduct can also undergo an additional cyclization step to a hemiacetal derivative, whereas no cyclization occurs in the case of ONE and a Michael adduct is identified. A Schiff base product initially formed when HNE is added to PE lipid can also further cyclize to a pyrrole derivative in contrast to ONE, where only a Schiff base product is isolated. The suggested reaction mechanism by quantum-chemical calculations is in a qualitative agreement with experimental yields of isolated products and is also additionally investigated by 1 H NMR measurements, FT-IR spectroscopy, and mass spectrometry experiments.

77 FR 67020 - Performance Review Board Appointments

Federal Register 2010, 2011, 2012, 2013, 2014

2012-11-08

..., Tommy Beck, Richard Belin, Alletta Berrigan, Michael Black, Michael Black, Steven Blanchard, Mary Josie..., Robert Reidenbach, Dennis Reynolds, Michael Rice, Bryan Roberson, Edwin Rountree, Carl Russ, David...

Enantioselective Conjugate Additions of α-Amino Radicals via Cooperative Photoredox and Lewis Acid Catalysis

PubMed Central

Espelt, Laura Ruiz; McPherson, Iain S.; Wiensch, Eric M.; Yoon, Tehshik P.

2015-01-01

We report the highly enantioselective addition of photogenerated α-amino radicals to Michael acceptors. This method features a dual-catalyst protocol that combines transition metal photoredox catalysis with chiral Lewis acid catalysis. The combination of these two powerful modes of catalysis provides an effective, general strategy to generate and control the reactivity of photogenerated reactive intermediates. PMID:25668687

The target-to-foils shift in simultaneous and sequential lineups.

PubMed

Clark, Steven E; Davey, Sherrie L

2005-04-01

A theoretical cornerstone in eyewitness identification research is the proposition that witnesses, in making decisions from standard simultaneous lineups, make relative judgments. The present research considers two sources of support for this proposal. An experiment by G. L. Wells (1993) showed that if the target is removed from a lineup, witnesses shift their responses to pick foils, rather than rejecting the lineups, a result we will term a target-to-foils shift. Additional empirical support is provided by results from sequential lineups which typically show higher accuracy than simultaneous lineups, presumably because of a decrease in the use of relative judgments in making identification decisions. The combination of these two lines of research suggests that the target-to-foils shift should be reduced in sequential lineups relative to simultaneous lineups. Results of two experiments showed an overall advantage for sequential lineups, but also showed a target-to-foils shift equal in size for simultaneous and sequential lineups. Additional analyses indicated that the target-to-foils shift in sequential lineups was moderated in part by an order effect and was produced with (Experiment 2) or without (Experiment 1) a shift in decision criterion. This complex pattern of results suggests that more work is needed to understand the processes which underlie decisions in simultaneous and sequential lineups.

Structural evidence for the partially oxidized dipyrromethene and dipyrromethanone forms of the cofactor of porphobilinogen deaminase: structures of the Bacillus megaterium enzyme at near-atomic resolution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Azim, N.; Deery, E.; Warren, M. J.

The enzyme porphobilinogen deaminase (PBGD; hydroxymethylbilane synthase; EC 2.5.1.61) catalyses a key early step in the biosynthesis of tetrapyrroles in which four molecules of the monopyrrole porphobilinogen are condensed to form a linear tetrapyrrole. Two near-atomic resolution structures of PBGD from B. megaterium are reported that demonstrate the time-dependent accumulation of partially oxidized forms of the cofactor, including one that possesses a tetrahedral C atom in the terminal pyrrole ring. The enzyme porphobilinogen deaminase (PBGD; hydroxymethylbilane synthase; EC 2.5.1.61) catalyses an early step of the tetrapyrrole-biosynthesis pathway in which four molecules of the monopyrrole porphobilinogen are condensed to form amore » linear tetrapyrrole. The enzyme possesses a dipyrromethane cofactor, which is covalently linked by a thioether bridge to an invariant cysteine residue (Cys241 in the Bacillus megaterium enzyme). The cofactor is extended during the reaction by the sequential addition of the four substrate molecules, which are released as a linear tetrapyrrole product. Expression in Escherichia coli of a His-tagged form of B. megaterium PBGD has permitted the X-ray analysis of the enzyme from this species at high resolution, showing that the cofactor becomes progressively oxidized to the dipyrromethene and dipyrromethanone forms. In previously solved PBGD structures, the oxidized cofactor is in the dipyromethenone form, in which both pyrrole rings are approximately coplanar. In contrast, the oxidized cofactor in the B. megaterium enzyme appears to be in the dipyrromethanone form, in which the C atom at the bridging α-position of the outer pyrrole ring is very clearly in a tetrahedral configuration. It is suggested that the pink colour of the freshly purified protein is owing to the presence of the dipyrromethene form of the cofactor which, in the structure reported here, adopts the same conformation as the fully reduced dipyrromethane form.« less

Biochemical Characterization and Structural Basis of Reactivity and Regioselectivity Differences between Burkholderia thailandensis and Burkholderia glumae 1,6-Didesmethyltoxoflavin N-Methyltransferase.

PubMed

Fenwick, Michael K; Almabruk, Khaled H; Ealick, Steven E; Begley, Tadhg P; Philmus, Benjamin

2017-08-01

Burkholderia glumae converts the guanine base of guanosine triphosphate into an azapteridine and methylates both the pyrimidine and triazine rings to make toxoflavin. Strains of Burkholderia thailandensis and Burkholderia pseudomallei have a gene cluster encoding seven putative biosynthetic enzymes that resembles the toxoflavin gene cluster. Four of the enzymes are similar in sequence to BgToxBCDE, which have been proposed to make 1,6-didesmethyltoxoflavin (1,6-DDMT). One of the remaining enzymes, BthII1283 in B. thailandensis E264, is a predicted S-adenosylmethionine (SAM)-dependent N-methyltransferase that shows a low level of sequence identity to BgToxA, which sequentially methylates N6 and N1 of 1,6-DDMT to form toxoflavin. Here we show that, unlike BgToxA, BthII1283 catalyzes a single methyl transfer to N1 of 1,6-DDMT in vitro. In addition, we investigated the differences in reactivity and regioselectivity by determining crystal structures of BthII1283 with bound S-adenosylhomocysteine (SAH) or 1,6-DDMT and SAH. BthII1283 contains a class I methyltransferase fold and three unique extensions used for 1,6-DDMT recognition. The active site structure suggests that 1,6-DDMT is bound in a reduced form. The plane of the azapteridine ring system is orthogonal to its orientation in BgToxA. In BthII1283, the modeled SAM methyl group is directed toward the p orbital of N1, whereas in BgToxA, it is first directed toward an sp 2 orbital of N6 and then toward an sp 2 orbital of N1 after planar rotation of the azapteridine ring system. Furthermore, in BthII1283, N1 is hydrogen bonded to a histidine residue whereas BgToxA does not supply an obvious basic residue for either N6 or N1 methylation.

Documentation in a Software Maintenance Environment.

DTIC Science & Technology

1987-08-28

Michael Jackson Diagrams 0...8217 ." " . ." ." ""’, " , "" " - . -’" ,," ’" " " "’" d t Review of Documentation Techniques Michael Jackson Diagrams Michael Jackson diagrams show data...coupling and cohesion. Logic is not represented in this technique, which thus is of limited value. Advantages: Michael Jackson diagrams are similar

An investigation of volcanic depressions. Part 4: Origin of Hole-in-the-ground, a maar in Central Oregon

NASA Technical Reports Server (NTRS)

Lorenz, V.

1971-01-01

Hole-in-the-Ground, a volcanic explosion crater, located in central Oregon is described. The morphology of the soil and rocks and the topography of the crater indicate the sequential happenings during the eruption. Geophysical measurements also indicate a domical intrusion below the crater floor, extending upward as a ring dike around the margins of the crater. The volume of ejecta was determined for four major eruptions. Varied analyses were made of the pyroclastic debris, rocks, cinders, and soil.

Tri-state oriented parallel processing system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tenenbaum, J.; Wallach, Y.

1982-08-01

An alternating sequential/parallel system, the MOPPS was introduced a few years ago and is modified despite the fact that it solved satisfactorily a number of real-time problems. The new system, the TOPPS is described and compared to MOPPS and two applications are chosen to prove it to be superior. The advantage of having a third basic, the ring mode, is illustrated when solving sets of linear equations with band matrices. The advantage of having independent I/O for the slaves is illustrated for biomedical signal analysis. 11 references.

Synthesis of isochromene-type scaffolds via single-flask Diels-Alder-[4 + 2]-annulation sequence of a silyl-substituted diene with menadione.

PubMed

Lee, Jihoon; Panek, James S

2014-06-20

A sequential Diels-Alder reaction/silicon-directed [4 + 2]-annulation was developed to assemble hydroisochromene-type ring systems from menadione 2. In the first step, a Diels-Alder of the 1-silyl-substituted butadiene 1 with 2 furnished an intermediate cyclic allylsilane. Subsequently, TMSOTf promoted a [4 + 2]-annulation through trapping of an oxonium, generated by condensation between an aldehyde and the TBS protected alcohol resulted in the formation of a cis-fused hydroisochromene 13.

Modeling of anisotropic properties of double quantum rings by the terahertz laser field.

PubMed

Baghramyan, Henrikh M; Barseghyan, Manuk G; Kirakosyan, Albert A; Ojeda, Judith H; Bragard, Jean; Laroze, David

2018-04-18

The rendering of different shapes of just a single sample of a concentric double quantum ring is demonstrated realizable with a terahertz laser field, that in turn, allows the manipulation of electronic and optical properties of a sample. It is shown that by changing the intensity or frequency of laser field, one can come to a new set of degenerated levels in double quantum rings and switch the charge distribution between the rings. In addition, depending on the direction of an additional static electric field, the linear and quadratic quantum confined Stark effects are observed. The absorption spectrum shifts and the additive absorption coefficient variations affected by laser and electric fields are discussed. Finally, anisotropic electronic and optical properties of isotropic concentric double quantum rings are modeled with the help of terahertz laser field.

Asymmetric synthesis of a potent, aminopiperidine-fused imidazopyridine dipeptidyl peptidase IV inhibitor.

PubMed

Xu, Feng; Corley, Edward; Zacuto, Michael; Conlon, David A; Pipik, Brenda; Humphrey, Guy; Murry, Jerry; Tschaen, David

2010-03-05

A practical asymmetric synthesis of a novel aminopiperidine-fused imidazopyridine dipeptidyl peptidase IV (DPP-4) inhibitor 1 has been developed. Application of a unique three-component cascade coupling with chiral nitro diester 7, which is easily accessed via a highly enantioselective Michael addition of dimethyl malonate to a nitrostyrene, allows for the assembly of the functionalized piperidinone skeleton in one pot. Through a base-catalyzed, dynamic crystallization-driven process, the cis-piperidionone 16a is epimerized to the desired trans isomer 16b, which is directly crystallized from the crude reaction stream in high yield and purity. Isomerization of the allylamide 16b in the presence of RhCl(3) is achieved without any epimerization of the acid/base labile stereogenic center adjacent to the nitro group on the piperidinone ring, while the undesired enamine intermediate is consumed to <0.5% by utilizing a trace amount of HCl generated from RhCl(3). The amino lactam 4, obtained through hydrogenation and hydrolysis, is isolated as its crystalline pTSA salt from the reaction solution directly, as such intramolecular transamidation has been dramatically suppressed via kinetic control. Finally, a Cu(I) catalyzed coupling-cyclization allows for the formation of the tricyclic structure of the potent DPP-4 inhibitor 1. The synthesis, which is suitable for large scale preparation, is accomplished in 23% overall yield.

Sequential addition reactions of two molecules of Grignard reagents to thioformamides.

PubMed

Murai, Toshiaki; Ui, Kazuki; Narengerile

2009-08-07

Sequential addition reactions of two molecules of Grignard reagents to thioformamides were found to yield tertiary amines in an efficient manner. The addition of two different Grignard reagents can be accomplished by using one equivalent of arylmagnesium reagent in the first step. In the second step, a variety of reagents such as alkyl, alkenyl, aryl, and alkynyl reagents were used to afford the corresponding amines in good to high yields.

The Rings with Identity Whose Additive Subgroups Are One-Sided Ideals

ERIC Educational Resources Information Center

Dobbs, David E.

2017-01-01

Let R be a ring with identity. Then {0} and R are the only additive subgroups of R if and only if R is isomorphic (as a ring with identity) to (exactly) one of {0}, Z/pZ for a prime number p. Also, each additive subgroup of R is a one-sided ideal of R if and only if R is isomorphic to (exactly) one of {0}, Z, Z/nZ for an integer n = 2. This note…

4. Photocopy of inkandwatercolor drawing (from St. Michael's Church) Rambusch, ...

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

4. Photocopy of ink-and-watercolor drawing (from St. Michael's Church) Rambusch, illustrator ca. 1932-37 INTERIOR, LOOKING NORTHEAST - St. Michael's Catholic Church, 519 East Third Street, Madison, Jefferson County, IN

Michael J. Fox: Spurring Research on Parkinson's

MedlinePlus

... on. Feature: Parkinson's Disease Michael J. Fox: Spurring Research on Parkinson's Past Issues / Winter 2014 Table of ... founded the Michael J. Fox Foundation for Parkinson's Research in the year 2000. Photo courtesy of Shutterstock " ...

Dignital Biological Converter

DTIC Science & Technology

2014-01-03

DARPA Contracting Officer: Michael Blackstone Submitted by: HEATHER GOUVIS Synthetic Genomics, Inc. 11149 NORTH TORREY PINES RD LA JOLLA, CA...Contracting Officer Representative (COR) Email: salit@nist.gov Michael Blackstone DARPA Contracting Officer Michael.Blackstone@darpa.mil DARPA

Biomimetically inspired asymmetric total synthesis of (+)-19-dehydroxyl arisandilactone A

NASA Astrophysics Data System (ADS)

Han, Yi-Xin; Jiang, Yan-Long; Li, Yong; Yu, Hai-Xin; Tong, Bing-Qi; Niu, Zhe; Zhou, Shi-Jie; Liu, Song; Lan, Yu; Chen, Jia-Hua; Yang, Zhen

2017-01-01

Complex natural products are a proven and rich source of disease-modulating drugs and of efficient tools for the study of chemical biology and drug discovery. The architectures of complex natural products are generally considered to represent significant barriers to efficient chemical synthesis. Here we describe a concise and efficient asymmetric synthesis of 19-dehydroxyl arisandilactone A--which belongs to a family of architecturally unique, highly oxygenated nortriterpenoids isolated from the medicinal plant Schisandra arisanensis. This synthesis takes place by means of a homo-Michael reaction, a tandem retro-Michael/Michael reaction, and Cu-catalysed intramolecular cyclopropanation as key steps. The proposed mechanisms for the homo-Michael and tandem retro-Michael/Michael reactions are supported by density functional theory (DFT) calculation. The developed chemistry may find application for the synthesis of its other family members of Schisandraceae nortriterpenoids.

KSC-08pd2573

NASA Image and Video Library

2008-09-05

CAPE CANAVERAL, Fla. – In the Payload Hazardous Servicing Facility at NASA’s Kennedy Space Center, crew members with the STS-125 mission get a close look at some of the equipment associated with their mission to service NASA’s Hubble Space Telescope. A technician, at left, provides information about the Soft Capture Mechanism on the Flight Support Structure to Mission Specialists Michael Good, Andrew Feustel and Mike Massimino. The mechanism will enable the future rendezvous, capture and safe disposal of NASA's Hubble Space Telescope by either a crewed or robotic mission. The ring-like device attaches to Hubble’s aft bulkhead. The STS-125 crew is taking part in a crew equipment interface test, which provides experience handling tools, equipment and hardware they will use on their mission. Space shuttle Atlantis is targeted to launch on the STS-125 mission Oct. 10. Photo credit: NASA/Kim Shiflett

Catalytic enantioselective synthesis of indanes by a cation-directed 5-endo-trig cyclization.

PubMed

Johnston, Craig P; Kothari, Abhishek; Sergeieva, Tetiana; Okovytyy, Sergiy I; Jackson, Kelvin E; Paton, Robert S; Smith, Martin D

2014-02-01

5-Endo-trig cyclizations are generally considered to be kinetically unfavourable, as described by Baldwin's rules. Consequently, observation of this mode of reaction under kinetic control is rare. This is usually ascribed to challenges in achieving appropriate approach trajectories for orbital overlap in the transition state. Here, we describe a highly enantio- and diastereoselective route to complex indanes bearing all-carbon quaternary stereogenic centres via a 5-endo-trig cyclization catalysed by a chiral ammonium salt. Through computation, the preference for the formally disfavoured 5-endo-trig Michael reaction over the formally favoured 5-exo-trig Dieckmann reaction is shown to result from thermodynamic contributions to the innate selectivity of the nucleophilic group, which outweigh the importance of the approach trajectory as embodied by Baldwin's rules. Our experimental and theoretical findings demonstrate that geometric and stereoelectronic constraints may not be decisive in the observed outcome of irreversible ring-closing reactions.

Molecular interactions between carbon nanotubes and ammonium ionic liquids and their catalysis properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Attri, Pankaj, E-mail: chem.pankaj@gmail.com; Bhatia, Rohit; Arora, Bharti

2014-10-15

Highlights: • We report interactions between multi-walled carbon nanotubes and ionic liquids. • Triethylammonium hydrogen phosphate ionic liquids are studied. • Raman spectroscopy is used to study interactions. • Morphological studies were carried out using scanning electron microscopy. • Bucky gel was used as catalyst for Michael reactions. - Abstract: A new catalytic method has been developed for the synthesis of aza/thia-Michael addition reactions of amines/thiols, which provide higher product yields. This catalyst is a combination of multi-walled carbon nanotubes (MWCNT) with triethylammonium hydrogen phosphate (TEAP) ionic liquid (IL), commonly referred to as bucky gel. In order to gain insightmore » into the interactions involved between IL and MWCNT, we utilised Raman spectroscopy for our analysis. The interactions between MWCNT with TEAP were clearly evidenced by the increasing intensity ratios and spectral shift in the wavelength for the Raman D and G bands of MWCNT. The morphological studies of the resulting composite materials of TEAP and MWCNT (bucky gel) were carried out using scanning electron microscopy (SEM). The key advantage of using bucky gel as a catalyst is that higher product yield is obtained in reduced reaction time for Michael reactions.« less

Ovalbumin-derived precursor peptides are transferred sequentially from gp96 and calreticulin to MHC I in the endoplasmic reticulum

PubMed Central

Kropp, Laura E.; Garg, Manish; Binder, Robert J.

2010-01-01

Cellular peptides generated by proteasomal degradation of proteins in the cytosol and destined for presentation by MHC I are associated with several chaperones. Hsp70, hsp90 and the TCP1-ring complex have been implicated as important cytosolic players for chaperoning these peptides. In this study we report that gp96 and calreticulin are essential for chaperoning peptides in the endoplasmic reticulum. Importantly we demonstrate that cellular peptides are transferred sequentially from gp96 to calreticulin and then to MHC I forming a relay line. Disruption of this relay line by removal of gp96 or calreticulin prevents the binding of peptides by MHC I and hence presentation of the MHC I-peptide complex on the cell surface. Our results are important for understanding how peptides are processed and trafficked within the endoplasmic reticulum before exiting in association with MHC I heavy chains and β2-microglobulin as a trimolecular complex. PMID:20410492

Catalytic asymmetric Michael reactions promoted by a lithium-free lanthanum-BINOL complex

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sasai, Hiroaki; Arai, Takayoshi; Shibasaki, Masakatsu

1994-02-23

In this communication, we report about a new lithium-free BINOL-lanthanum complex, which is quite effective in catalytic asymmetric Michael reaction. We have succeeded in developing effective asymmetric base catalysts, in particular, asymmetric ester enolate catalysts for asymmetric Michael reactions. Two asymmetric lanthanum complexes are now available, namely, BINOL-lanthanum-lithium complex, which is quite effective in catalytic asymmetric nitrosaldol reactions, and a new lithium-free BINOL-lanthanum ester enolate complex, that is very effective in catalytic asymmetric Michael reactions. The two complexes complement each other in their ability to catalyze asymmetric nitroaldol and asymmetric Michael reactions. 14 refs., 1 fig., 2 tabs.

Performance of Oil Pumping Rings: An Analytical and Experimental Study

NASA Technical Reports Server (NTRS)

Eusepi, M. W.; Walowit, J. A.; Pinkus, O.; Holmes, P.

1986-01-01

A steady-state design computer program was developed to predict the performance of pumping rings as functions of geometry, applied loading, speed, ring modulus, and fluid viscosity. Additional analyses were developed to predict transient behavior of the ring and the effects of temperature rises occurring in the hydrodynamic film between the ring and shaft. The analysis was initially compared with previous experimental data and then used to design additional rings for further testing. Tests were performed with Rulon, carbon-graphite, and babbit rings. The design analysis was used to size all of the rings and to select the ranges of clearances, thickness, and loading. Although full quantitative agreement was lacking, relative agreement existed in that rings that were predicted to perform well theoretically, generally performed well experimentally. Some causes for discrepanices between theory and experiment are believed to be due to starvation, leakage past the secondary seal at high pressures, and uncertainties in the small clearances and local inlet temperatures to the pumping ring. A separate preliminary analysis was performed for a pumping Leningrader seal. This anlaysis can be used to predict the film thickness and flow rate thr ough the seal as a function of pressure, speed, loading, and geometry.

Formation of Exotic Networks of Water Clusters in Helium Droplets Facilitated by the Presence of Neon Atoms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Douberly, Gary E.; Miller, Roger E.; Xantheas, Sotiris S.

Water clusters are formed in helium droplets via the sequential capture of monomers. One or two neon atoms are added to each droplet prior to the addition of water. The infrared spectrum of the droplet ensemble reveals several signatures of polar, water tetramer clusters having dipole moments between 2D and 3D. Comparison with ab initio computations supports the assignment of the cluster networks to noncyclic “3+1” clusters, which are ~5.3 kcal/mol less stable than the global minimum nonpolar cyclic tetramer. The (H2O)3Ne + H2O ring insertion barrier is sufficiently large, such that evaporative helium cooling is capable of kinetically quenchingmore » the nonequilibrium tetramer system prior to its rearrangement to the lower energy cyclic species. To this end, the reported process results in the formation of exotic water cluster networks that are either higher in energy than the most stable gas-phase analogs or not even stable in the gas phase.« less

Does No One Read Vygotsky's Words? Commentary on Glassman

ERIC Educational Resources Information Center

Gredler, Margaret; Shields, Carol

2004-01-01

In the May 2001 issue of "Educational Researcher," Michael Glassman proposed several commonalities in the thinking of John Dewey and Lev Vygotsky. However, in addition to general problems in the article (misstatements about scholars' writings and a reliance on unsupported inferences), the discussion misconstrues major concepts and topics addressed…

EXAMINATION OF QUINONE TOXICITY USING YEAST SACCHAROMYCES CEREVISIAE MODEL SYSTEM. (R827352C007)

EPA Science Inventory

The toxicity of quinones is generally thought to occur by two mechanisms: the formation of covalent bonds with biological molecules by Michael addition chemistry and the catalytic reduction of oxygen to superoxide and other reactive oxygen species (ROS) (redox cycling). In an ...

Nano-organocatalyst: Magnetically retrievable ferrite-anchored glutathione for microwave-assisted Paal-Knorr reaction, Aza-Michael addition and pyrazole synthesis

EPA Science Inventory

Postsynthetic surface modification of magnetic nanoparticles by glutathione imparts desirable chemical functionality and enables the generation of catalytic sites on the surfaces of ensuing organocatalysts. In this article, we discuss the developments, unique activity and high s...

Chain Dynamic Formulations for Multibody System Tracked Vehicles (Preprint)

DTIC Science & Technology

2013-03-06

Michael Wallin 1 Ahmed K. Aboubakr 1 Paramsothy Jayakumar 2 Michael D. Letherwood 2 Ashraf Hamed 1 Ahmed A. Shabana 1...5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Michael Wallin; Ahmed Aboubakr; Paramsothy Jayakumar ; Michael Letherwood; Ashraf Hamed 5d...Taylor & Francis/CRC, Boca Raton, Florida. 16. Shabana, A. A., Hamed, A. M., Mohamed, A. A., Jayakumar , P., and Letherwood, M. D. 2012, “Use of B

NINTH INTERIM STATUS REPORT: MODEL 9975 PCV O-RING FIXTURE LONG-TERM LEAK PERFORMANCE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daugherty, W.

2014-08-06

A series of experiments to monitor the aging performance of Viton® GLT O-rings used in the Model 9975 package has been ongoing since 2004 at the Savannah River National Laboratory. One approach has been to periodically evaluate the leak performance of O-rings being aged in mock-up 9975 Primary Containment Vessels (PCVs) at elevated temperatures. Other methods such as compression-stress relaxation (CSR) tests and field surveillance are also on-going to evaluate O-ring behavior. Seventy tests using PCV mock-ups were assembled and heated to temperatures ranging from 200 to 450 ºF. They were leak-tested initially and have been tested periodically to determinemore » if they continue to meet the leak-tightness criterion defined in ANSI standard N14.5-97. Due to material substitution, fourteen additional tests were initiated in 2008 with GLT-S O-rings heated to temperatures ranging from 200 to 400 ºF. High temperature aging continues for 23 GLT O-ring fixtures at 200 – 270 ºF. Room temperature leak test failures have been experienced in all of the GLT O-ring fixtures aging at 350 ºF and higher temperatures, and in 8 fixtures aging at 300 ºF. The earliest 300 °F GLT O-ring fixture failure was observed at 34 months. The remaining GLT O-ring fixtures aging at 300 ºF have been retired from testing following more than 5 years at temperature without failure. No failures have yet been observed in GLT O-ring fixtures aging at 200 ºF for 72 - 96 months, which bounds O-ring temperatures anticipated during storage in K-Area Complex (KAC). Based on expectations that the 200 ºF fixtures will remain leak-tight for a significant period yet to come, 2 additional fixtures began aging in 2011 at 270 ºF, with hopes that they may reach a failure condition before the 200 ºF fixtures, thus providing additional time to failure data. High temperature aging continues for 6 GLT-S O-ring fixtures at 200 – 300 ºF. Room temperature leak test failures have been experienced in all 8 of the GLT-S O-ring fixtures aging at 350 and 400 ºF. No failures have yet been observed in GLT-S O-ring fixtures aging at 200 - 300 ºF for 54 - 57 months. No additional O-ring failures have been observed since the last interim report was issued. Aging and periodic leak testing will continue for the remaining PCV fixtures. Additional irradiation of several fixtures is recommended to maintain a balance between thermal and radiation exposures similar to that experienced in storage, and to show the degree of consistency of radiation response between GLT and GLT-S O-rings.« less

Heating and cooling of the neutral ISM in the NGC 4736 circumnuclear ring

NASA Astrophysics Data System (ADS)

van der Laan, T. P. R.; Armus, L.; Beirao, P.; Sandstrom, K.; Groves, B.; Schinnerer, E.; Draine, B. T.; Smith, J. D.; Galametz, M.; Wolfire, M.; Croxall, K.; Dale, D.; Herrera Camus, R.; Calzetti, D.; Kennicutt, R. C.

2015-03-01

The manner in which gas accretes and orbits within circumnuclear rings has direct implications for the star formation process. In particular, gas may be compressed and shocked at the inflow points, resulting in bursts of star formation at these locations. Afterwards the gas and young stars move together through the ring. In addition, star formation may occur throughout the ring, if and when the gas reaches sufficient density to collapse under gravity. These two scenarios for star formation in rings are often referred to as the "pearls-on-a-string" and "popcorn" paradigms. In this paper, we use new Herschel/PACS observations, obtained as part of the KINGFISH open time key program, along with archival Spitzer and ground-based observations from the SINGS Legacy project, to investigate the heating and cooling of the interstellar medium in the nearby star-forming ring galaxy, NGC 4736. By comparing spatially resolved estimates of the stellar far-ultraviolet flux available for heating, with the gas and dust cooling derived from the far-infrared continuum and line emission, we show that while star formation is indeed dominant at the inflow points in NGC 4736, additional star formation is needed to balance the gas heating and cooling throughout the ring. This additional component most likely arises from the general increase in gas density in the ring over its lifetime. Our data provide strong evidence, therefore, for a combination of the two paradigms for star formation in the ring in NGC 4736.

The effectiveness of zinc supplementation in men with isolated hypogonadotropic hypogonadism.

PubMed

Liu, Yan-Ling; Zhang, Man-Na; Tong, Guo-Yu; Sun, Shou-Yue; Zhu, Yan-Hua; Cao, Ying; Zhang, Jie; Huang, Hong; Niu, Ben; Li, Hong; Guo, Qing-Hua; Gao, Yan; Zhu, Da-Long; Li, Xiao-Ying

2017-01-01

A multicenter, open-label, randomized, controlled superiority trial with 18 months of follow-up was conducted to investigate whether oral zinc supplementation could further promote spermatogenesis in males with isolated hypogonadotropic hypogonadism (IHH) receiving sequential purified urinary follicular-stimulating hormone/human chorionic gonadotropin (uFSH/hCG) replacement. Sixty-seven Chinese male IHH patients were recruited from the Departments of Endocrinology in eight tertiary hospitals and randomly allocated into the sequential uFSH/hCG group (Group A, n = 34) or the sequential uFSH plus zinc supplementation group (Group B, n = 33). In Group A, patients received sequential uFSH (75 U, three times a week every other 3 months) and hCG (2000 U, twice a week) treatments. In Group B, patients received oral zinc supplementation (40 mg day-1 ) in addition to the sequential uFSH/hCG treatment given to patients in Group A. The primary outcome was the proportion of patients with a sperm concentration ≥1.0 × 106 ml-1 during the 18 months. The comparison of efficacy between Groups A and B was analyzed. Nineteen of 34 (55.9%) patients receiving sequential uFSH/hCG and 20 of 33 (60.6%) patients receiving sequential uFSH/hCG plus zinc supplementation achieved sperm concentrations ≥1.0 × 106 ml-1 by intention to treat analyses. No differences between Group A and Group B were observed as far as the efficacy of inducing spermatogenesis (P = 0.69). We concluded that the sequential uFSH/hCG plus zinc supplementation regimen had a similar efficacy to the sequential uFSH/hCG treatment alone. The additional improvement of 40 mg day-1 oral zinc supplementation on spermatogenesis and masculinization in male IHH patients is very subtle.

A survey of candidate missions to explore Saturn's rings

NASA Technical Reports Server (NTRS)

Wells, W. C.; Price, M. J.

1972-01-01

The ring system around Saturn is discussed. Exploration of the rings is required for an understanding of their origin and the hazard they represent to spacecraft near Saturn. In addition the rings may provide useful clues to the origin of the solar system. This study examines the problem of ring system exploration and recommends a sequence of missions which will collect the data required.

Michael E. Himmel | NREL

Science.gov Websites

E. Himmel Photo of Michael E. Himmel Michael Himmel Senior Research Fellow I-Molecular Biology ;Towards a molecular-level theory of carbohydrate processivity," Curr. Opinion Biotechnol. (2014 University, Department of Biochem. & Molecular Biol., Distinguished Alumnus (2014) Battelle Memorial

Lineup composition, suspect position, and the sequential lineup advantage.

PubMed

Carlson, Curt A; Gronlund, Scott D; Clark, Steven E

2008-06-01

N. M. Steblay, J. Dysart, S. Fulero, and R. C. L. Lindsay (2001) argued that sequential lineups reduce the likelihood of mistaken eyewitness identification. Experiment 1 replicated the design of R. C. L. Lindsay and G. L. Wells (1985), the first study to show the sequential lineup advantage. However, the innocent suspect was chosen at a lower rate in the simultaneous lineup, and no sequential lineup advantage was found. This led the authors to hypothesize that protection from a sequential lineup might emerge only when an innocent suspect stands out from the other lineup members. In Experiment 2, participants viewed a simultaneous or sequential lineup with either the guilty suspect or 1 of 3 innocent suspects. Lineup fairness was varied to influence the degree to which a suspect stood out. A sequential lineup advantage was found only for the unfair lineups. Additional analyses of suspect position in the sequential lineups showed an increase in the diagnosticity of suspect identifications as the suspect was placed later in the sequential lineup. These results suggest that the sequential lineup advantage is dependent on lineup composition and suspect position. (c) 2008 APA, all rights reserved

Structure and Function Study of Phi29 DNA packaging motor

NASA Astrophysics Data System (ADS)

Fang, Huaming

A powerful nanomotor is employed by the tailed dsDNA virus to package the genome into a preformed protein shell during the process of replication. The bacteriophage phi29 is an excellent model for investigating the viral DNA packaging mechanism. The phi29 DNA packaging motor is composed of three ring structures: the dodecameric connector ring, the hexameric pRNA ring and the hexameric ATPase gp16 ring. The connector is the central hub for the DNA to enter and to exit. There are four positively charged lysine rings scattered inside the highly negatively charged connector channel. It is speculated that these positive charged lysine rings may play active roles during DNA packaging in many models. To test this prevalent view, the basic lysine residues were mutated to neutral alanines and the pH environment was altered. Amazingly, the results were beyond expectation. Neither the DNA translocation nor the one-way traffic property of the channel were measurably influenced by the alteration of the charge of lysine residues when the basic lysine residues mutated to neutral alanines or the pH environment changed to acid or basic. The ATPase or the terminase is the central part of the viral DNA packaging motor. The phi29 ATPase is highly hydrophobic and tends to aggregate in solution. A green fluorescent protein tag (eGFP) fused to the N-terminus of gp16 enhanced its solubility and stability. The eGFP-gp16 showed similar activity to wild type gp16 and was easily detected by fluorescent instruments. The interaction between eGFP-gp16 and DNA in the various conditions were investigated by electrophoretic mobility shift assay, FRET and sucrose gradient. gamma-S-ATP dramatically increased gp16 binding affinity to DNA and ATP, ADP, phosphate could release gp16 from gp16-DNA-gamma-S-ATP complex. The sliding of gp16 out of the gp16-DNA-gamma-S-ATP complex could be blocked by addition of Steptavidin to ends of dsDNA which is conjugated with biotins. Also, we found that six eGFP-gp16 molecules were required to bind to one short dsDNA molecule. The inhibitive curve of Walker B mutant gp16 analyzed by binomial distribution model showed that one inactive mutant gp16 in the gp16 ring could block the function of the motor and the stoichiometry of gp16 was six. These findings facilitate our understanding of the molecular mechanism of viral DNA packaging: a novel viral DNA packaging model "push through a one-way valve" was proposed. In this model, the connector functioned as a valve to allow DNA to enter but prevented it from sliding out during DNA packaging; the six subunits in the gp16 ring acted sequentially to push DNA into the connector channel. ATP binding of gp16 induced a conformation change with a high affinity for dsDNA. Then, the ATP was hydrolyzed which resulted in the movement of subdomains in this individual gp16 subunit and DNA was pushed forward, followed by the double helix of dsDNA being brought forward to the adjacent subunit in the gp16 ring. The elucidation of the viral DNA packaging mechanism holds great potential for developing artificial motors for delivering drugs and other molecular cargos.

Experimenatal analysis of the effect of cartilaginous rings on human tracheobronchial flow

NASA Astrophysics Data System (ADS)

Montoya Segnini, Jose; Bocanegra Evans, Humberto; Castillo, Luciano

2016-11-01

We present a set of high-resolution PIV experiments carried out in a refractive index-matched model of a trachea with cartilage rings at Re 2800. Results show a higher vorticity along the walls of the trachea in the model with cartilaginous rings as well as small recirculation areas on the upstream side of the wall cavities created by the rings. Furthermore, the ringed model experiences higher shear stress in the trachea due to the sudden change in the wall position created by the rings. Additionally, small recirculation areas are identified in the cavities between rings. For the smooth model, a stronger separation bubble is observed at the bronchi entrance, generating a stronger shear layer and increasing the wall shear stress on the bottom bronchi wall. The differences observed go against the notion that the main airway, i.e. trachea and main bronchi, may be modeled as smooth. Our results suggest that cartilage rings will have an impact on the wall shear stress and may affect particle deposition, which is of importance in inhaled drug delivery and pollutant deposition in the airway. Additionally, the effects introduced by the rings may change the flow characteristics in further generations.

Enantioselective and regiodivergent copper-catalyzed conjugate addition of trialkylaluminium reagents to extended nitro-Michael acceptors.

PubMed

Tissot, Matthieu; Müller, Daniel; Belot, Sébastien; Alexakis, Alexandre

2010-06-18

The first highly enantioselective and regiodivergent conjugate addition of trialkylaluminium reagents to nitrodienes and nitroenynes is described. By a design of the substrate and a fine-tuning of the reaction conditions, it is possible to selectively form the 1,4- or 1,6-adduct. The same combination of catalyst, copper source, and a ferrocene-based phosphine ligand afforded enantioselectivities up to 95% and 91%, respectively.

Harnessing case isolation and ring vaccination to control Ebola.

PubMed

Wells, Chad; Yamin, Dan; Ndeffo-Mbah, Martial L; Wenzel, Natasha; Gaffney, Stephen G; Townsend, Jeffrey P; Meyers, Lauren Ancel; Fallah, Mosoka; Nyenswah, Tolbert G; Altice, Frederick L; Atkins, Katherine E; Galvani, Alison P

2015-05-01

As a devastating Ebola outbreak in West Africa continues, non-pharmaceutical control measures including contact tracing, quarantine, and case isolation are being implemented. In addition, public health agencies are scaling up efforts to test and deploy candidate vaccines. Given the experimental nature and limited initial supplies of vaccines, a mass vaccination campaign might not be feasible. However, ring vaccination of likely case contacts could provide an effective alternative in distributing the vaccine. To evaluate ring vaccination as a strategy for eliminating Ebola, we developed a pair approximation model of Ebola transmission, parameterized by confirmed incidence data from June 2014 to January 2015 in Liberia and Sierra Leone. Our results suggest that if a combined intervention of case isolation and ring vaccination had been initiated in the early fall of 2014, up to an additional 126 cases in Liberia and 560 cases in Sierra Leone could have been averted beyond case isolation alone. The marginal benefit of ring vaccination is predicted to be greatest in settings where there are more contacts per individual, greater clustering among individuals, when contact tracing has low efficacy or vaccination confers post-exposure protection. In such settings, ring vaccination can avert up to an additional 8% of Ebola cases. Accordingly, ring vaccination is predicted to offer a moderately beneficial supplement to ongoing non-pharmaceutical Ebola control efforts.

Design, synthesis and biological evaluation of novel hydroxy-phenyl-1H-benzimidazoles as radical scavengers and UV-protective agents.

PubMed

Bino, Alessia; Baldisserotto, Anna; Scalambra, Emanuela; Dissette, Valeria; Vedaldi, Daniela Ester; Salvador, Alessia; Durini, Elisa; Manfredini, Stefano; Vertuani, Silvia

2017-12-01

An ever-increasing incidence of skin neoplastic diseases is registered. Therefore, it is important to protect the skin from the UV radiation that reaches the epidermis and dermis but also to block ROS generated by them. Our attention was attracted in developing new compounds provided with both UV filtering and antioxidant capacities. To this end, 2-phenyl-1H-benzimidazole-5-sulfonic acid (PBSA), a known UV filter, was selected as lead compound for its lack of antioxidant activity, high water solubility and good safety profile. PBSA was sequentially modified introducing hydroxyls on the phenyl ring and also substituting the functional group in position 5 of the benzimidazole ring. At the end of the synthetic study, a new, very potent class of antioxidants has been obtained. Surprisingly some of the developed molecules, while devoid of significant UV-filtering activity was endowed with potent UV-filtering booster capability if associated with known commercial UVB and UVA filters.

78 FR 42748 - Virginia Resource Advisory Committee Meetings

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-17

... each meeting, contact: Michael Williams, Public Affairs Specialist, Supervisor's Office, 540-265-5173... building in order to view comments. FOR FURTHER INFORMATION CONTACT: Michael Williams, Public Affairs... for time for oral comments must be sent to Michael Williams, Public Affairs Specialist, George...

Synthesis of Triazole Derivatives of Levoglucosenone As Promising Anticancer Agents: Effective Exploration of the Chemical Space through retro-aza-Michael//aza-Michael Isomerizations.

PubMed

Tsai, Yi-Hsuan; Borini Etichetti, Carla M; Di Benedetto, Carolina; Girardini, Javier E; Martins, Felipe Terra; Spanevello, Rolando A; Suárez, Alejandra G; Sarotti, Ariel M

2018-04-06

The design and synthesis of biomass-derived triazoles and the in vitro evaluation as potential anticancer agents are described. The discovery of base-catalyzed retro-aza-Michael//aza-Michael isomerizations allowed the exploration of the chemical space by affording novel types of triazoles, difficult to obtain otherwise. Following this strategy, 2,4-disubstituted 1,2,3-triazoles could be efficiently obtained from the corresponding 1,4-disubstituted analogues.

Butyl rubber O-ring seals: Revision of test procedures for stockpile materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Domeier, L.A.; Wagter, K.R.

1996-12-01

Extensive testing showed little correlation between test slab and O-ring performance. New procedures, comparable to those used with the traditional test slabs, were defined for hardness, compression set, and tensile property testing on sacrificial O-ring specimens. Changes in target performance values were made as needed and were, in one case, tightened to reflect the O-ring performance data. An additional study was carried out on O-ring and slab performance vs cure cycle and showed little sensitivity of material performance to large changes in curing time. Aging and spectra of certain materials indicated that two sets of test slabs from current vendormore » were accidently made from EPDM rather than butyl rubber. Random testing found no O-rings made from EPDM. As a result, and additional spectroscope test will be added to the product acceptance procedures to verify the type of rubber compound used.« less

The Gemini NICI Planet-Finding Campaign: asymmetries in the HD 141569 disc

NASA Astrophysics Data System (ADS)

Biller, Beth A.; Liu, Michael C.; Rice, Ken; Wahhaj, Zahed; Nielsen, Eric; Hayward, Thomas; Kuchner, Marc J.; Close, Laird M.; Chun, Mark; Ftaclas, Christ; Toomey, Douglas W.

2015-07-01

We report here the highest resolution near-IR imaging to date of the HD 141569A disc taken as part of the NICI (near infrared coronagraphic imager) Science Campaign. We recover four main features in the NICI images of the HD 141569 disc discovered in previous Hubble Space Telescope (HST) imaging: (1) an inner ring/spiral feature. Once deprojected, this feature does not appear circular. (2) An outer ring which is considerably brighter on the western side compared to the eastern side, but looks fairly circular in the deprojected image. (3) An additional arc-like feature between the inner and outer ring only evident on the east side. In the deprojected image, this feature appears to complete the circle of the west side inner ring and (4) an evacuated cavity from 175 au inwards. Compared to the previous HST imaging with relatively large coronagraphic inner working angles (IWA), the NICI coronagraph allows imaging down to an IWA of 0.3 arcsec. Thus, the inner edge of the inner ring/spiral feature is well resolved and we do not find any additional disc structures within 175 au. We note some additional asymmetries in this system. Specifically, while the outer ring structure looks circular in this deprojection, the inner bright ring looks rather elliptical. This suggests that a single deprojection angle is not appropriate for this system and that there may be an offset in inclination between the two ring/spiral features. We find an offset of 4 ± 2 au between the inner ring and the star centre, potentially pointing to unseen inner companions.

Re-constructing nutritional history of Serengeti wildebeest from stable isotopes in tail hair: seasonal starvation patterns in an obligate grazer.

PubMed

Rysava, K; McGill, R A R; Matthiopoulos, J; Hopcraft, J G C

2016-07-15

Nutritional bottlenecks often limit the abundance of animal populations and alter individual behaviours; however, establishing animal condition over extended periods of time using non-invasive techniques has been a major limitation in population ecology. We test if the sequential measurement of δ(15) N values in a continually growing tissue, such as hair, can be used as a natural bio-logger akin to tree rings or ice cores to provide insights into nutritional stress. Nitrogen stable isotope ratios were measured by continuous-flow isotope-ratio mass spectrometry (IRMS) from 20 sequential segments along the tail hairs of 15 migratory wildebeest. Generalized Linear Models were used to test for variation between concurrent segments of hair from the same individual, and to compare the δ(15) N values of starved and non-starved animals. Correlations between δ(15) N values in the hair and periods of above-average energy demand during the annual cycle were tested using Generalized Additive Mixed Models. The time series of nitrogen isotope ratios in the tail hair are comparable between strands from the same individual. The most likely explanation for the pattern of (15) N enrichment between individuals is determined by life phase, and especially the energetic demands associated with reproduction. The mean δ(15) N value of starved animals was greater than that of non-starved animals, suggesting that higher δ(15) N values correlate with periods of nutritional stress. High δ(15) N values in the tail hair of wildebeest are correlated with periods of negative energy balance, suggesting they may be used as a reliable indicator of the animal's nutritional history. This technique might be applicable to other obligate grazers. Most importantly, the sequential isotopic analysis of hair offers a continuous record of the chronic condition of wildebeest (effectively converting point data into time series) and allows researchers to establish the animal's nutritional diary. © 2016 The Authors. Rapid Communications in Mass Spectrometry Published by John Wiley & Sons Ltd.

NREL: U.S. Life Cycle Inventory Database - Project Management Team

Science.gov Websites

Project Management Team Information about the U.S. Life Cycle Inventory (LCI) Database project management team is listed on this page. Additional project information is available about the U.S. LCI Mechanical Engineering, Colorado State University Professional History Michael has worked as a Senior

76 FR 5186 - National Protection and Programs Directorate; Agency Information Collection Activities; Office of...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-28

...), Office of Infrastructure Protection (IP), will submit the following information collection request (ICR... Paperwork Reduction Act of 1995 (Pub. L. 104-13, 44 U.S.C. Chapter 35). IP is soliciting comments concerning... INFORMATION CONTACT: If additional information is required, contact DHS/NPPD/IP, Michael Beland, (703) 235...

(Re)Imagining Black Boyhood: Toward a Critical Framework for Educational Research

ERIC Educational Resources Information Center

Dumas, Michael J.; Nelson, Joseph Derrick

2016-01-01

Drawing on critical childhood studies, Michael J. Dumas and Joseph Derrick Nelson argue that Black boyhood is socially unimagined and unimaginable, largely due to the devalued position and limited consideration of Black girls and boys within the broader social conception of childhood. In addition, the "crisis" focus of the public…

HIGHLY DIASTEREOSELECTIVE MICHAEL ADDITION OF FLAVANONE TO ITS CHALCONE PRECURSOR UNDER SOLVENT-FREE CONDITIONS USING MICROWAVES

EPA Science Inventory

Substituted 2'-hydroxychalcones were found to give an equilibrium mixture of the starting chalcone and the corresponding flavanone in 4:6 - 1:3 ratio in the presence of various supports and MW irradiation. MW irradiation of 2'-hydroxychalcones in the presence of DBU gave two hit...

Stereoselective syntheses of four diastereomers of 3,9,12-trihydroxycalamenene via a benzobicyclo[3.3.1] intermediate.

PubMed

Sun, Yongquan; Yu, Binxun; Wang, Xiaolei; Tang, Shibing; She, Xuegong; Pan, Xinfu

2010-06-18

The highly stereoselective syntheses of four diastereomers of natural 3,9,12-trihydroxycalamenene are described. The syntheses highlight the utility of an unusual framework of benzobicyclo[3.3.1] lactones, which were accomplished via an intramolecular Friedel-Crafts-type Michael addition of alpha,beta-unsaturated lactones.

Education, Eco-Progressivism and the Nature of School Reform

ERIC Educational Resources Information Center

Roberts, Jay

2007-01-01

This article is an attempt to critique some of the limitations of dominant school reform discourses in education, drawing upon the work of Michel Foucault, Michael Apple, Maxine Greene, and Dennis Carlson, in addition to writers in the emerging field of what might be called "eco-progressivism." The intersections between ecology and education can…

Ring cavity for a Raman capillary waveguide amplifier

DOEpatents

Kurnit, N.A.

1981-01-27

A regenerative ring amplifier and regenerative ring oscillator are described which function to feed back a portion of the Stokes signal to complete the ring cavity. The ring cavity configuration allows the CO/sub 2/ laser pump signal and Stokes signal to copropagate through the Raman capillary waveguide amplifier. A Raman capillary waveguide amplifier is also provided in the return leg of the ring cavity to increase gain without increasing the round trip time. Additionally, the ring cavity can be designed such that the amplified Stokes signal is synchronous with the mode-locked spikes of the incoming CO/sub 2/ laser pump signal.

Ring cavity for a Raman capillary waveguide amplifir

DOEpatents

Kurnit, N.A.

1981-01-27

A regenerative ring amplifier and regenerative ring oscillator are described which function to feed back a portion of the Stokes signal to complete the ring cavity. The ring cavity configuration allows the CO/sub 2/ laser pump signal and Stokes signal to copropagate through the Raman capillary waveguide amplifier. A Raman capillary waveguide amplifier is also provided in the return leg of the ring cavity to increase gain without increasing the round trip time. Additionally, the ring cavity can be designed such that the amplified Stokes signal is synchronous with the mode-locked spikes of the incoming CO/sub 2/ laser pump signal.

Ring cavity for a raman capillary waveguide amplifier

DOEpatents

Kurnit, Norman A.

1983-07-19

A regenerative ring amplifier and regenerative ring oscillator which function to feed back a portion of the Stokes signal to complete the ring cavity. The ring cavity configuration allows the CO.sub.2 laser pump signal and Stokes signal to copropagate through the Raman capillary waveguide amplifier. A Raman capillary waveguide amplifier is also provided in the return leg of the ring cavity to increase gain without increasing the round trip time. Additionally, the ring cavity can be designed such that the amplifier Stokes signal is synchronous with the mode-locked spikes of the incoming CO.sub.2 laser pump signal.

Wavepacket revivals in monolayer and bilayer graphene rings.

PubMed

García, Trinidad; Rodríguez-Bolívar, Salvador; Cordero, Nicolás A; Romera, Elvira

2013-06-12

We have studied the existence of quantum revivals in graphene quantum rings within a simplified model. The time evolution of a Gaussian-populated wavepacket shows revivals in monolayer and bilayer graphene rings. We have also studied this behavior for quantum rings in a perpendicular magnetic field. We have found that revival time is an observable that shows different values for monolayer and bilayer graphene quantum rings. In addition, the revival time shows valley degeneracy breaking.

Improving the identification accuracy of senior witnesses: do prelineup questions and sequential testing help?

PubMed

Memon, Amina; Gabbert, Fiona

2003-04-01

Eyewitness research has identified sequential lineup testing as a way of reducing false lineup choices while maintaining accurate identifications. The authors examined the usefulness of this procedure for reducing false choices in older adults. Young and senior witnesses viewed a crime video and were later presented with target present orabsent lineups in a simultaneous or sequential format. In addition, some participants received prelineup questions about their memory for a perpetrator's face and about their confidence in their ability to identify the culprit or to correctly reject the lineup. The sequential lineup reduced false choosing rates among young and older adults in target-absent conditions. In target-present conditions, sequential testing significantly reduced the correct identification rate in both age groups.

76 FR 10352 - Keyser, Michael J.; Notice of Filing

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-24

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ID-6495-000] Keyser, Michael J.; Notice of Filing Take notice that on February 15, 2011, Michael J. Keyser submitted for filing, an application for authority to hold interlocking positions, pursuant to section 305(b) of the...

A novel sequential vegetable production facility for life support system in space

NASA Astrophysics Data System (ADS)

Liu, Hui; Berkovich, Yuliy A.; Liu, Hong; Fu, Yuming; Shao, Lingzhi; Erokhin, A. N.; Wang, Minjuan

2012-07-01

Vegetable cultivation plays a crucial role for dietary supplements and psychosocial benefits of the crew during manned space flight. The idea of onboard vegetables cultivation was generally proposed as the first step of food regeneration in life support system of space. Here a novel sequential vegetable production facility was developed, which was able to simulate microgravity conditions and carry out modularized-cultivation of leaf-vegetables. Its growth chamber (GC) had conic form and volume of 0.12 m ^{3}. Its planting surface of 0.154 m ^{2} was comprised of six ring-shaped root modules with a fibrous ion-exchange resin substrate. Root modules were fastened to a central porous tube supplying water, and moved on along with plant growth. The total illuminated crop area of 0.567 m ^{2} was provided by a combination of both red and white light emitting diodes distributed on the GC cone internal surface. In tests with a 24-hr photoperiod, the productivity of the facility at 0.3 kW for lettuce achieved 254.3 g eatable biomass per week. Compared to lettuce from market, the quality of lettuce of the facility did not change significantly during long-term cultivation. Our results demonstrate that the facility is high efficiency in vegetable production, and basically meets the application requirements of space microgravity environment. Keywords:, vegetable; modularized-cultivation; sequential production; life support system

Synthesis of structurally diverse benzosuberene analogues and their biological evaluation as anti-cancer agents

PubMed Central

Tanpure, Rajendra P.; George, Clinton S.; Strecker, Tracy E.; Devkota, Laxman; Tidmore, Justin K.; Lin, Chen-Ming; Herdman, Christine A.; MacDonough, Matthew T.; Sriram, Madhavi; Chaplin, David J.; Trawick, Mary Lynn; Pinney, Kevin G.

2014-01-01

Diversely functionalized, fused aryl-alkyl ring systems hold a prominent position as well-established molecular frameworks for a variety of anti-cancer agents. The benzosuberene (6,7 fused, also referred to as dihydro-5H-benzo[7]annulene and benzocycloheptene) ring system has emerged as a valuable molecular core component for the development of inhibitors of tubulin assembly, which function as antiproliferative anti-cancer agents and, in certain cases, as vascular disrupting agents (VDAs). Both a phenolic-based analogue (known as KGP18, compound 39) and its corresponding amine-based congener (referred to as KGP156, compound 45), which demonstrate strong inhibition of tubulin assembly (low micromolar range) and potent cytotoxicity (picomolar range for KGP18 and nanomolar range for KGP156) are noteworthy examples of such benzosuberene-based compounds. In order to extend the structure-activity relationship (SAR) knowledge base related to benzosuberene anti-cancer agents, a series of eleven analogues (including KGP18) were prepared in which the methoxylation pattern on the pendant aryl ring as well as functional group incorporation on the fused aryl ring were varied. The synthetic approach to these compounds featured a sequential Wittig olefination, reduction, Eaton's reagent-mediated cyclization strategy to achieve the core benzosuberone intermediate, and represented a higher-yielding synthesis of KGP18 (which we prepared previously through a ring-expansion strategy). Incorporation of a fluorine or chlorine atom at the 1-position of the fused aryl ring or replacement of one of the methoxy groups with hydrogen (on the pendant aryl ring of KGP18) led to benzosuberene analogues that were both strongly inhibitory against tubulin assembly (IC50 approximately 1.0 M) and strongly cytotoxic against selected human cancer cell lines (for example, GI50 = 5.47 nM against NCI-H460 cells with fluorobenzosuberene analogue 37). A water-soluble phosphate prodrug salt of KGP18 (referred to as KGP265, compound 44) and a water-soluble serinamide salt (compound 48) of KGP156 were also synthesized and evaluated in this study. PMID:24183586

Doing It All: Michael Sullivan--Weeks Public Library, NH

ERIC Educational Resources Information Center

Library Journal, 2005

2005-01-01

Michael Sullivan is a juggler--not a metaphorical one, a real one. He's also a library director, storyteller, competitive chess player, poet, speaker, and former children's librarian who continues to work with the kids in his community. This article summarizes the accomplishments and work of Michael Sullivan.

Michael J. Meaney: Award for Distinguished Scientific Contributions

ERIC Educational Resources Information Center

American Psychologist, 2012

2012-01-01

Presents Michael J. Meaney as one of the winners of the American Psychological Association's Award for Distinguished Scientific Contributions (2012). Michael J. Meaney has taken the phenomenon of "handling" of newborn rats and opened a new area of investigation that has given new meaning to epigenetics via his work demonstrating transgenerational…

Jack Michael's Motivation

ERIC Educational Resources Information Center

Miguel, Caio F.

2013-01-01

Among many of Jack Michael's contributions to the field of behavior analysis is his behavioral account of motivation. This paper focuses on the concept of "motivating operation" (MO) by outlining its development from Skinner's (1938) notion of "drive." Conceptually, Michael's term helped us change our focus on…

75 FR 22436 - Michael Williams-Control Exemption-St. Maries River Railroad, Inc.

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-28

... DEPARTMENT OF TRANSPORTATION Surface Transportation Board [Docket No. FD 35365] Michael Williams-Control Exemption-St. Maries River Railroad, Inc. Michael Williams (applicant),\\1\\ a noncarrier, has filed a verified notice of exemption to acquire control of St. Maries River Railroad, Inc. (STMA), a Class...

Studying Teachers and Schools: Michael Pressley's Legacy and Directions for Future Research

ERIC Educational Resources Information Center

Mohan, Lindsey; Lundeberg, Mary A.; Reffitt, Kelly

2008-01-01

Much of Michael Pressley's work during the past decade focused on the nature of highly effective, engaging literacy instruction. Michael Pressley believed that studying effective teachers and schools had the potential to influence more engaging and effective teaching, especially in underresourced schools. First, we describe the grounded…

Language and Intercultural Education: An Interview with Michael Byram

ERIC Educational Resources Information Center

Porto, Melina

2013-01-01

This article reports an interview with Michael Byram, Professor Emeritus, University of Durham in the United Kingdom, during his visit to Argentina in September 2011. Michael Byram is one of the main international referents in intercultural education. The interview addresses issues such as language education, intercultural and citizenship…

Base-promoted one-pot tandem reaction of 3-(1-alkynyl)chromones under microwave irradiation to functionalized amino-substituted xanthones.

PubMed

Liu, Yang; Huang, Liping; Xie, Fuchun; Hu, Youhong

2010-09-17

A base-promoted one-pot tandem reaction has been developed from 3-(1-alkynyl)chromones with various acetonitriles to afford functionalized amino-substituted xanthones 3 under microwave irradiation. This tandem process involves multiple reactions, such as Michael addition/cyclization/1,2-addition, without a transition metal catalyst. This method provides an efficient approach to build up natural product-like diversified amino-substituted xanthone scaffolds rapidly.

Similar Neural Correlates for Language and Sequential Learning: Evidence from Event-Related Brain Potentials

PubMed Central

Christiansen, Morten H.; Conway, Christopher M.; Onnis, Luca

2011-01-01

We used event-related potentials (ERPs) to investigate the time course and distribution of brain activity while adults performed (a) a sequential learning task involving complex structured sequences, and (b) a language processing task. The same positive ERP deflection, the P600 effect, typically linked to difficult or ungrammatical syntactic processing, was found for structural incongruencies in both sequential learning as well as natural language, and with similar topographical distributions. Additionally, a left anterior negativity (LAN) was observed for language but not for sequential learning. These results are interpreted as an indication that the P600 provides an index of violations and the cost of integration of expectations for upcoming material when processing complex sequential structure. We conclude that the same neural mechanisms may be recruited for both syntactic processing of linguistic stimuli and sequential learning of structured sequence patterns more generally. PMID:23678205

Novel Fiber-Optic Ring Acoustic Emission Sensor

PubMed Central

Han, Xiaole; Xia, Dong; Liu, Taolin; Lang, Hao

2018-01-01

Acoustic emission technology has been applied to many fields for many years. However, the conventional piezoelectric acoustic emission sensors cannot be used in extreme environments, such as those with heavy electromagnetic interference, high pressure, or strong corrosion. In this paper, a novel fiber-optic ring acoustic emission sensor is proposed. The sensor exhibits high sensitivity, anti-electromagnetic interference, and corrosion resistance. First, the principle of a novel fiber-optic ring sensor is introduced. Different from piezoelectric and other fiber acoustic emission sensors, this novel sensor includes both a sensing skeleton and a sensing fiber. Second, a heterodyne interferometric demodulating method is presented. In addition, a fiber-optic ring sensor acoustic emission system is built based on this method. Finally, fiber-optic ring acoustic emission experiments are performed. The novel fiber-optic ring sensor is glued onto the surface of an aluminum plate. The 150 kHz standard continuous sinusoidal signals and broken lead signals are successfully detected by the novel fiber-optic ring acoustic emission sensor. In addition, comparison to the piezoelectric acoustic emission sensor is performed, which shows the availability and reliability of the novel fiber-optic ring acoustic emission sensor. In the future, this novel fiber-optic ring acoustic emission sensor will provide a new route to acoustic emission detection in harsh environments. PMID:29342858

Novel Fiber-Optic Ring Acoustic Emission Sensor.

PubMed

Wei, Peng; Han, Xiaole; Xia, Dong; Liu, Taolin; Lang, Hao

2018-01-13

Acoustic emission technology has been applied to many fields for many years. However, the conventional piezoelectric acoustic emission sensors cannot be used in extreme environments, such as those with heavy electromagnetic interference, high pressure, or strong corrosion. In this paper, a novel fiber-optic ring acoustic emission sensor is proposed. The sensor exhibits high sensitivity, anti-electromagnetic interference, and corrosion resistance. First, the principle of a novel fiber-optic ring sensor is introduced. Different from piezoelectric and other fiber acoustic emission sensors, this novel sensor includes both a sensing skeleton and a sensing fiber. Second, a heterodyne interferometric demodulating method is presented. In addition, a fiber-optic ring sensor acoustic emission system is built based on this method. Finally, fiber-optic ring acoustic emission experiments are performed. The novel fiber-optic ring sensor is glued onto the surface of an aluminum plate. The 150 kHz standard continuous sinusoidal signals and broken lead signals are successfully detected by the novel fiber-optic ring acoustic emission sensor. In addition, comparison to the piezoelectric acoustic emission sensor is performed, which shows the availability and reliability of the novel fiber-optic ring acoustic emission sensor. In the future, this novel fiber-optic ring acoustic emission sensor will provide a new route to acoustic emission detection in harsh environments.

Optimal pacing modes after cardiac transplantation: is synchronisation of recipient and donor atria beneficial?

PubMed Central

Parry, Gareth; Malbut, Katie; Dark, John H; Bexton, Rodney S

1992-01-01

Objective—To investigate the response of the transplanted heart to different pacing modes and to synchronisation of the recipient and donor atria in terms of cardiac output at rest. Design—Doppler derived cardiac output measurements at three pacing rates (90/min, 110/min and 130/min) in five pacing modes: right ventricular pacing, donor atrial pacing, recipient-donor synchronous pacing, donor atrial-ventricular sequential pacing, and synchronous recipient-donor atrial-ventricular sequential pacing. Patients—11 healthy cardiac transplant recipients with three pairs of epicardial leads inserted at transplantation. Results—Donor atrial pacing (+11% overall) and donor atrial-ventricular sequential pacing (+8% overall) were significantly better than right ventricular pacing (p < 0·001) at all pacing rates. Synchronised pacing of recipient and donor atrial segments did not confer additional benefit in either atrial or atrial-ventricular sequential modes of pacing in terms of cardiac output at rest at these fixed rates. Conclusions—Atrial pacing or atrial-ventricular sequential pacing appear to be appropriate modes in cardiac transplant recipients. Synchronisation of recipient and donor atrial segments in this study produced no additional benefit. Chronotropic competence in these patients may, however, result in improved exercise capacity and deserves further investigation. PMID:1389737

Better together: reduced compliance after sequential versus simultaneous bilateral hearing aids fitting.

PubMed

Lavie, Limor; Banai, Karen; Attias, Joseph; Karni, Avi

2014-03-01

The purpose of this study was to determine the effects of sequential versus simultaneous bilateral hearing aids fitting on patient compliance. Thirty-six older adults with hearing impairment participated in this study. Twelve were fitted with bilateral hearing aids simultaneously. The remaining participants were fitted sequentially: One hearing aid (to the left or to the right ear) was used initially; 1 month later, the other ear was also fitted with a hearing aid for bilateral use. Self-reports on usefulness and compliance were elicited after the first and second months of hearing aid use. In addition, the number of hours the hearing aids were used was extracted from the data loggings of each device. Simultaneous fitting resulted in high levels of compliance and consistent usage throughout the study period. Sequential fitting resulted in abrupt reduction in compliance and hours of use once the second hearing aid was added, both in the clinical scoring and in the data loggings. Simultaneous fitting of bilateral hearing aids results in better compliance compared with sequential fitting. The addition of a second hearing aid after a relatively short period of monaural use may lead to inconsistent use of both hearing aids.

Peptide/protein-polymer conjugates: synthetic strategies and design concepts.

PubMed

Gauthier, Marc A; Klok, Harm-Anton

2008-06-21

This feature article provides a compilation of tools available for preparing well-defined peptide/protein-polymer conjugates, which are defined as hybrid constructs combining (i) a defined number of peptide/protein segments with uniform chain lengths and defined monomer sequences (primary structure) with (ii) a defined number of synthetic polymer chains. The first section describes methods for post-translational, or direct, introduction of chemoselective handles onto natural or synthetic peptides/proteins. Addressed topics include the residue- and/or site-specific modification of peptides/proteins at Arg, Asp, Cys, Gln, Glu, Gly, His, Lys, Met, Phe, Ser, Thr, Trp, Tyr and Val residues and methods for producing peptides/proteins containing non-canonical amino acids by peptide synthesis and protein engineering. In the second section, methods for introducing chemoselective groups onto the side-chain or chain-end of synthetic polymers produced by radical, anionic, cationic, metathesis and ring-opening polymerization are described. The final section discusses convergent and divergent strategies for covalently assembling polymers and peptides/proteins. An overview of the use of chemoselective reactions such as Heck, Sonogashira and Suzuki coupling, Diels-Alder cycloaddition, Click chemistry, Staudinger ligation, Michael's addition, reductive alkylation and oxime/hydrazone chemistry for the convergent synthesis of peptide/protein-polymer conjugates is given. Divergent approaches for preparing peptide/protein-polymer conjugates which are discussed include peptide synthesis from synthetic polymer supports, polymerization from peptide/protein macroinitiators or chain transfer agents and the polymerization of peptide side-chain monomers.

Ring cavity for a Raman capillary waveguide amplifier

DOEpatents

Kurnit, N.A.

1983-07-19

Disclosed is a regenerative ring amplifier and regenerative ring oscillator which function to feed back a portion of the Stokes signal to complete the ring cavity. The ring cavity configuration allows the CO[sub 2] laser pump signal and Stokes signal to copropagate through the Raman capillary waveguide amplifier. A Raman capillary waveguide amplifier is also provided in the return leg of the ring cavity to increase gain without increasing the round trip time. Additionally, the ring cavity can be designed such that the amplifier Stokes signal is synchronous with the mode-locked spikes of the incoming CO[sub 2] laser pump signal. 6 figs.

78 FR 2391 - CAlifornians for Renewable Energy, Inc., Michael E. Boyd, Robert M. Sarvey v. Pacific Gas and...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-11

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. RP13-436-000] CAlifornians for Renewable Energy, Inc., Michael E. Boyd, Robert M. Sarvey v. Pacific Gas and Electric Company... Energy Regulatory Commission (FERC); CAlifornians for Renewable Energy, Inc., Michael E. Boyd, and Robert...

Interview with Michael Apple: The Biography of a Public Intellectual

ERIC Educational Resources Information Center

Peters, Michael A.

2015-01-01

Michael W. Apple is the John Bascom Professor of Curriculum and Instruction and Educational Policy Studies in the Departments of Curriculum and Instruction (CI) and Educational Policy Studies (EPS) at the University of Wisconsin-Madison School of Education where he has taught since 1970. Michael Apple is one of the foremost educational theorists…

Markets, Marx, Modernity and Mathematics Education: A Response to Michael Apple.

ERIC Educational Resources Information Center

Gates, Peter

This paper is a response to Michael Apple's paper, "What Postmodernists Forget: Cultural Capital and Official Knowledge." The paper advocates Michael's identification of the current dangers and processes of the growth of new right ideologies in the development of subjectivity, society, and education. The differences in success in the education…

77 FR 61596 - Wheatley, Michael I.; Garrison, Drummond E.; Notice of Filing

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-10

...] Wheatley, Michael I.; Garrison, Drummond E.; Notice of Filing Take notice that on September 28, 2012, Michael I. Wheatley and Drummond E. Garrison submitted for filing, an application for authority to hold... the ``eFiling'' link at http://www.ferc.gov . Persons unable to file electronically should submit an...

76 FR 624 - Proposed Information Collection (Patient Satisfaction Survey Michael E. DeBakey Home Care Program...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-05

... Collection (Patient Satisfaction Survey Michael E. DeBakey Home Care Program) Activity: Comment Request... Form 10-0476).'' SUPPLEMENTARY INFORMATION: Title: Patient Satisfaction Survey Michael E. DeBakey Home... satisfaction with the quality of services/care provided by home care program staff. An agency may not conduct...

Mechanistic Kinetic Modeling of Thiol-Michael Addition Photopolymerizations via Photocaged "Superbase" Generators: An Analytical Approach.

PubMed

Claudino, Mauro; Zhang, Xinpeng; Alim, Marvin D; Podgórski, Maciej; Bowman, Christopher N

2016-11-08

A kinetic mechanism and the accompanying mathematical framework are presented for base-mediated thiol-Michael photopolymerization kinetics involving a photobase generator. Here, model kinetic predictions demonstrate excellent agreement with a representative experimental system composed of 2-(2-nitrophenyl)propyloxycarbonyl-1,1,3,3-tetramethylguanidine (NPPOC-TMG) as a photobase generator that is used to initiate thiol-vinyl sulfone Michael addition reactions and polymerizations. Modeling equations derived from a basic mechanistic scheme indicate overall polymerization rates that follow a pseudo-first-order kinetic process in the base and coreactant concentrations, controlled by the ratio of the propagation to chain-transfer kinetic parameters ( k p / k CT ) which is dictated by the rate-limiting step and controls the time necessary to reach gelation. Gelation occurs earlier as the k p / k CT ratio reaches a critical value, wherefrom gel times become nearly independent of k p / k CT . The theoretical approach allowed determining the effect of induction time on the reaction kinetics due to initial acid-base neutralization for the photogenerated base caused by the presence of protic contaminants. Such inhibition kinetics may be challenging for reaction systems that require high curing rates but are relevant for chemical systems that need to remain kinetically dormant until activated although at the ultimate cost of lower polymerization rates. The pure step-growth character of this living polymerization and the exhibited kinetics provide unique potential for extended dark-cure reactions and uniform material properties. The general kinetic model is applicable to photobase initiators where photolysis follows a unimolecular cleavage process releasing a strong base catalyst without cogeneration of intermediate radical species.

Acrolein with an alpha, beta-unsaturated Carbonyl Group Inhibits LPS-induced Homodimerization of Toll-like Receptor 4

USDA-ARS?s Scientific Manuscript database

Acrolein is a highly electrophilic a,ß-unsaturated aldehyde present in a number of environmental sources, especially cigarette smoke. It reacts strongly with the thiol groups of cysteine residues by Michael addition and has been reported to inhibit nuclear factor-kB (NF-kB) activation by lipopolysac...

DC-Powered Jumping Ring

NASA Astrophysics Data System (ADS)

Jeffery, Rondo N.; Amiri, Farhang

2016-02-01

The classroom jumping ring demonstration is nearly always performed using alternating current (AC), in which the ring jumps or flies off the extended iron core when the switch is closed. The ring jumps higher when cooled with liquid nitrogen (LN2). We have performed experiments using DC to power the solenoid and find similarities and significant differences from the AC case. In particular, the ring does not fly off the core but rises a short distance and then falls back. If the ring jumps high enough, the rising and the falling motion of the ring does not follow simple vertical motion of a projectile. This indicates that there are additional forces on the ring in each part of its motion. Four possible stages of the motion of the ring with DC are identified, which result from the ring current changing directions during the jump in response to a changing magnetic flux through the moving ring.

NASA Catches Tropical Storm Leslie and Hurricane Michael in the Atlantic

NASA Image and Video Library

2017-12-08

This visible image of Tropical Storm Leslie and Hurricane Michael was taken by the MODIS instrument aboard both NASA's Aqua and Terra satellites on Sept. 9 at 12:50 p.m. EDT. Credit: NASA Goddard/MODIS Rapid Response Team -- Satellite images from two NASA satellites were combined to create a full picture of Tropical Storm Leslie and Hurricane Michael spinning in the Atlantic Ocean. Imagery from NASA's Aqua and Terra satellites showed Leslie now past Bermuda and Michael in the north central Atlantic, and Leslie is much larger than the smaller, more powerful Michael. Images of each storm were taken by the Moderate Resolution Imaging Spectroradiometer, or MODIS instrument that flies onboard both the Aqua and Terra satellites. Both satellites captured images of both storms on Sept. 7 and Sept. 10. The image from Sept. 7 showed a much more compact Michael with a visible eye. By Sept. 10, the eye was no longer visible in Michael and the storm appeared more elongated from south to north. To continue reading go to: 1.usa.gov/NkUPqn NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Length dependence of a halo orthosis on cervical immobilization.

PubMed

Triggs, K J; Ballock, R T; Byrne, T; Garfin, S R

1993-02-01

This study was designed to observe the length dependence of a well-molded fiberglass body cast attached to a halo on motion restriction in an unstable cadaveric cervical spine. Also, by using this technique, comparison between the immobilization provided by a body cast and that provided by a standard premolded polyethylene halo vest could be made. Extreme cervical instability was created on adult cadavers. A halo ring was applied and then attached to a fiberglass body cast or to a polyethylene halo vest. Sequential lateral cervical radiographs were obtained during maximum flexion as the body cast was shortened from the level of the iliac crests to the level of the xiphoid process. Radiographic motion was also assessed within the polyethylene halo vest. Results revealed minimal motion difference as the fiberglass body cast was sequentially shortened. In contrast, motions within the polyethylene halo vest were variable. These results suggest that cervical immobilization may be relatively independent of support structure length and that immobilization can be maintained by a well-fitting halo vest extending to the level of the xiphoid process.

Reversible switching of fluorophore property based on intrinsic conformational transition of adenylate kinase during its catalytic cycle.

PubMed

Fujii, Akira; Hirota, Shun; Matsuo, Takashi

2013-07-17

Adenylate kinase shows a conformational transition (OPEN and CLOSED forms) during substrate binding and product release to mediate the phosphoryl transfer between ADP and ATP/AMP. The protein motional characteristics will be useful to construct switching systems of fluorophore properties caused by the catalytic cycle of the enzyme. This paper demonstrates in situ reversible switching of a fluorophore property driven by the conformational transition of the enzyme. The pyrene-conjugated mutant adenylate kinase is able to switch the monomer/excimer emission property of pyrene on addition of ADP or P(1)P(5)-di(adenosine-5')pentaphosphate (Ap5A, a transition state analog). The observation under the dilute condition (~0.1 μM) indicates that the emission spectral change was caused by the motion of a protein molecule and not led by protein-protein interactions through π-π stacking of pyrene rings. The switching can be reversibly conducted by using hexokinase-coupling reaction. The fashion of the changes in emission intensities at various ligand concentrations is different between ADP, Mg(2+)-bound ADP, and Mg(2+)-bound Ap5A. The emission property switching is repeatable by a sequential addition of a substrate in a one-pot process. It is proposed that the property of a synthetic molecule on the enzyme surface is switchable in response to the catalytic cycle of adenylate kinase.

Interview with J. Michael Thompson

ERIC Educational Resources Information Center

Randall, Mary Elisabeth

2004-01-01

J. Michael Thompson is the Vice Provost for Enrollment Management and Dean of Admission and Financial Aid at the University of Southern California. J. Michael has worked in higher education for more than 30 years in a variety of roles at small private and mid-sized and large public universities, and now at USC, a large private university. He has…

Veteran’s Health Care Issues

DTIC Science & Technology

2007-11-30

Affairs Dr. Michael J. Kussman , in U.S. Congress, House Committee on Veterans’ Affairs Subcommittee on Oversight and Investigations, hearing on...Health, Department of Veterans Affairs, Michael Kussman , in U.S. Congress, House Committee on Appropriations, Subcommittee on Military Construction...Department of Veterans Affairs Dr. Michael J. Kussman , in U.S. Congress, House Committee on Veterans’ Affairs Subcommittee on Oversight and

78 FR 6851 - Proposed Information Collection (Patient Satisfaction Survey Michael E. DeBakey Home Care Program...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-31

... (Patient Satisfaction Survey Michael E. DeBakey Home Care Program) Activity: Comment Request AGENCY... Satisfaction Survey Michael E. DeBakey Home Care Program, VA Form 10-0476. OMB Control Number: 2900-0775. Type... gather feedback from patients regarding their satisfaction with the quality of services/care provided by...

Michael Young and the Curriculum Field in South Africa

ERIC Educational Resources Information Center

Hoadley, Ursula

2015-01-01

The paper addresses the question of what we should make of Michael Young's recent work with respect to curriculum theory by considering the particular case of South African curriculum reform. The paper thus traces two trajectories: the evolution of Michael Young's ideas over time and South African curriculum reform in the post-apartheid period.…

Synthesis and antiproliferative activity of peracetylated 2-amino-1,2-dideoxy-1-nitro-d-glycero-l-manno and d-glycero-d-talo heptitols.

PubMed

Luque-Agudo, Verónica; González Gutiérrez, Ana María; Lagunes, Irene; López Galindo, Federico; Padrón, José M; Román, Emilio; Serrano, José Antonio; Gil, María Victoria

2016-12-01

Michael additions between carbohydrate derived nitroalkenes and several aliphatic and aromatic amines proceeded in a stereoselective way, leading to peracetylated 2-amino-1,2-dideoxy-1-nitro-heptitols. In addition, the antiproliferative activity of some of the new adducts has been studied. The results allowed to identify lead compounds which show GI 50 values in the range 1.7-19μM. Copyright © 2016 Elsevier Inc. All rights reserved.

2-Hydroxybenzophenone as a Chemical Auxiliary for the Activation of Ketiminoesters for Highly Enantioselective Addition to Nitroalkenes under Bifunctional Catalysis.

PubMed

Guerrero-Corella, Andrea; Esteban, Francisco; Iniesta, Manuel; Martín-Somer, Ana; Parra, Mario; Díaz-Tendero, Sergio; Fraile, Alberto; Alemán, Jose

2018-05-04

An organocatalytic system is presented for the Michael addition of monoactivated glycine ketimine ylides with a bifunctional catalyst. The ketimine bears an ortho hydroxy group, which increases the acidity of the methylene hydrogen atoms and enhances the reactivity, thus allowing the synthesis of a large variety of α,γ-diamino acid derivatives with excellent stereoselectivity. © 2018 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

Investigation of Air-Liquid Interface Rings in Buffer Preparation Vessels: the Role of Slip Agents.

PubMed

Shi, Ting; Ding, Wei; Kessler, Donald W; De Mas, Nuria; Weaver, Douglas G; Pathirana, Charles; Martin, Russell D; Mackin, Nancy A; Casati, Michael; Miller, Scott A; Pla, Itzcoatl A

2016-01-01

Air-liquid interface rings were observed on the side walls of stainless steel buffer vessels after certain downstream buffer preparations. Those rings were resistant to regular cleaning-in-place procedures but could be removed by manual means. To investigate the root cause of this issue, multiple analytical techniques, including liquid chromatography with tandem mass spectrometry detection (LC-MS/MS), high-resolution accurate mass liquid chromatography with mass spectrometry, nuclear magnetic resonance, Fourier transform infrared spectroscopy, and scanning electron microscopy with energy-dispersive X-ray spectroscopy have been employed to characterize the chemical composition of air-liquid interface rings. The main component of air-liquid interface rings was determined to be slip agents, and the origin of the slip agents can be traced back to their presence on raw material packaging liners. Slip agents are commonly used in plastic industry as additives to reduce the coefficient of friction during the manufacturing process of thin films. To mitigate this air-liquid interface ring issue, an alternate liner with low slip agent was identified and implemented with minimal additional cost. We have also proactively tested the packaging liners of other raw materials currently used in our downstream buffer preparation to ensure slip agent levels are appropriate. Air-liquid interface rings were observed on the side walls of stainless steel buffer vessels after certain downstream buffer preparations. To investigate the root cause of this issue, multiple analytical techniques have been employed to characterize the chemical composition of air-liquid interface rings. The main components of air-liquid interface rings were determined to be slip agents, which are common additives used in the manufacturing process of thin films. The origin of the slip agents can be traced back to their presence on certain raw material packaging liners. To mitigate this air-liquid interface ring issue, an alternate liner with low slip agent was identified and implemented. © PDA, Inc. 2016.

Sequential contrast-enhanced MR imaging of the penis.

PubMed

Kaneko, K; De Mouy, E H; Lee, B E

1994-04-01

To determine the enhancement patterns of the penis at magnetic resonance (MR) imaging. Sequential contrast material-enhanced MR images of the penis in a flaccid state were obtained in 16 volunteers (12 with normal penile function and four with erectile dysfunction). Subjects with normal erectile function showed gradual and centrifugal enhancement of the corpora cavernosa, while those with erectile dysfunction showed poor enhancement with abnormal progression. Sequential contrast-enhanced MR imaging provides additional morphologic information for the evaluation of erectile dysfunction.

STS-109 Crew Interviews: Michael J. Massimino

NASA Technical Reports Server (NTRS)

2002-01-01

STS-109 Mission Specialist Michael J. Massimino is seen during a prelaunch interview. He answers questions about his inspiration to become an astronaut, his career path, and his most memorable experiences. He gives details on the mission's goals and objectives, which focus on the refurbishing of the Hubble Space Telescope, and his role in the mission. He explains the plans for the rendezvous of the Columbia Orbiter with the Hubble Space Telescope. He provides details and timelines for each of the planned Extravehicular Activities (EVAs), which include replacing the solar arrays, changing the Power Control Unit, installing the Advanced Camera for Surveys (ACS), and installing a new Cryocooler for the Near Infrared Camera and Multi-Object Spectrometer (NICMOS). He also describes the break-out plan in place for these spacewalks. The interview ends with Massimino explaining the details of a late addition to the mission's tasks, which is to replace a reaction wheel on the Hubble Space Telescope.

STS-107 Crew Interviews: Michael Anderson, Mission Specialist

NASA Technical Reports Server (NTRS)

2002-01-01

STS-107 Mission Specialist 3 and Payload Commander Michael Anderson is seen during this preflight interview, where he gives a quick overview of the mission before answering questions about his inspiration to become an astronaut and his career path. He outlines his role in the mission in general, and specifically in conducting onboard science experiments. He discusses the following instruments and sets of experiments in detail: CM2 (Combustion Module 2), FREESTAR (Fast Reaction Enabling Science Technology and Research, MEIDEX (Mediterranean Israeli Dust Experiment) and MGM (Mechanics of Granular Materials). Anderson also mentions on-board activities and responsibilities during launch and reentry, mission training, and microgravity research. In addition, he touches on the dual work-shift nature of the mission, the use of crew members as research subjects including pre and postflight monitoring activities, the emphasis on crew safety during training and the value of international cooperation.

Central catalytic domain of BRAP (RNF52) recognizes the types of ubiquitin chains and utilizes oligo-ubiquitin for ubiquitylation.

PubMed

Shoji, Shisako; Hanada, Kazuharu; Ohsawa, Noboru; Shirouzu, Mikako

2017-09-07

Really interesting new gene (RING)-finger protein 52 (RNF52), an E3 ubiquitin ligase, is found in eukaryotes from yeast to humans. Human RNF52 is known as breast cancer type 1 susceptibility protein (BRCA1)-associated protein 2 (BRAP or BRAP2). The central catalytic domain of BRAP comprises four subdomains: nucleotide-binding α/β plait (NBP), really interesting new gene (RING) zinc finger, ubiquitin-specific protease (UBP)-like zinc finger (ZfUBP), and coiled-coil (CC). This domain architecture is conserved in RNF52 orthologs; however, the domain's function in the ubiquitin system has not been delineated. In the present study, we discovered that the RNF52 domain, comprising NBP-RING-ZfUBP-CC, binds to ubiquitin chains (oligo-ubiquitin) but not to the ubiquitin monomers, and can utilize various ubiquitin chains for ubiquitylation and auto-ubiquitylation. The RNF52 domain preferentially bound to M1- and K63-linked di-ubiquitin chains, weakly to K27-linked chains, but not to K6-, K11-, or K48-linked chains. The binding preferences of the RNF52 domain for ubiquitin-linkage types corresponded to ubiquitin usage in the ubiquitylation reaction, except for K11-, K29-, and K33-linked chains. Additionally, the RNF52 domain directly ligated the intact M1-linked, tri-, and tetra-ubiquitin chains and recognized the structural alterations caused by the phosphomimetic mutation of these ubiquitin chains. Full-length BRAP had nearly the same specificity for the ubiquitin-chain types as the RNF52 domain alone. Mass spectrometry analysis of oligomeric ubiquitylation products, mediated by the RNF52 domain, revealed that the ubiquitin-linkage types and auto-ubiquitylation sites depend on the length of ubiquitin chains. Here, we propose a model for the oligomeric ubiquitylation process, controlled by the RNF52 domain, which is not a sequential assembly process involving monomers. © 2017 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

The orbits of the uranian satellites and rings, the gravity field of the uranian system, and the orientation of the pole of Uranus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jacobson, R. A., E-mail: robert.jacobson@jpl.nasa.gov

2014-11-01

French et al. determined the orbits of the Uranian rings, the orientation of the pole of Uranus, and the gravity harmonics of Uranus from Earth-based and Voyager ring occultations. Jacobson et al. determined the orbits of the Uranian satellites and the masses of Uranus and its satellites from Earth-based astrometry and observations acquired with the Voyager 2 spacecraft; they used the gravity harmonics and pole from French et al. Jacobson and Rush reconstructed the Voyager 2 trajectory and redetermined the Uranian system gravity parameters, satellite orbits, and ring orbits in a combined analysis of the data used previously augmented withmore » additional Earth-based astrometry. Here we report on an extension of that work that incorporates additional astrometry and ring occultations together with improved data processing techniques.« less

Interferometric ring lasers and optical devices

DOEpatents

Hohimer, J.P.; Craft, D.C.

1995-03-14

Two ring diode lasers are optically coupled together to produce tunable, stable output through a Y-junction output coupler which may also be a laser diode or can be an active waveguide. These devices demonstrate a sharp peak in light output with an excellent side-mode-rejection ratio. The rings can also be made of passive or active waveguide material. With additional rings the device is a tunable optical multiplexer/demultiplexer. 11 figs.

Interferometric ring lasers and optical devices

DOEpatents

Hohimer, John P.; Craft, David C.

1995-01-01

Two ring diode lasers are optically coupled together to produce tunable, stable output through a Y-junction output coupler which may also be a laser diode or can be an active waveguide. These devices demonstrate a sharp peak in light output with an excellent side-mode-rejection ratio. The rings can also be made of passive or active waveguide material. With additional rings the device is a tunable optical multiplexer/demultiplexer.

Seeing ghosts - Photometry of Saturn's G Ring

NASA Technical Reports Server (NTRS)

Showalter, Mark R.; Cuzzi, Jeffrey N.

1993-01-01

Saturn's faint and narrow G Ring is only visible to the eye in two Voyager images, each taken at a rather high solar phase angle of about 160 deg. In this paper we introduce a new photometric technique for averaging across multiple Voyager images, and use it to detect the G Ring at several additional viewing geometries. The resultant phase curve suggests that the G Ring is composed of dust particles obeying a very steep power-law size distribution. The dust is generally smaller than that seen in other rings, ranging down to 0.03 micron. The G Ring occupies the region between orbital radii 166,000 and 173,000 km, and has a peak somewhat closer to the inner edge. Based on these limits, we demonstrate that Voyager 2 passed through and directly sampled this ring during its 1981 encounter with Saturn. Combined analysis of additional data sets suggests that a population of larger bodies is also present in the G Ring; these bodies occupy a narrower band near the observed peak and are likely the source for the visible dust. Based on some preliminary dynamical models, we propose that these larger bodies represent leftover debris from the collisional breakup of a small moon in Saturn's distant past.

In vitro contraction of cytokinetic ring depends on myosin II but not on actin dynamics.

PubMed

Mishra, Mithilesh; Kashiwazaki, Jun; Takagi, Tomoko; Srinivasan, Ramanujam; Huang, Yinyi; Balasubramanian, Mohan K; Mabuchi, Issei

2013-07-01

Cytokinesis in many eukaryotes involves the contraction of an actomyosin-based contractile ring. However, the detailed mechanism of contractile ring contraction is not fully understood. Here, we establish an experimental system to study contraction of the ring to completion in vitro. We show that the contractile ring of permeabilized fission yeast cells undergoes rapid contraction in an ATP- and myosin-II-dependent manner in the absence of other cytoplasmic constituents. Surprisingly, neither actin polymerization nor its disassembly is required for contraction of the contractile ring, although addition of exogenous actin-crosslinking proteins blocks ring contraction. Using contractile rings generated from fission yeast cytokinesis mutants, we show that not all proteins required for assembly of the ring are required for its contraction in vitro. Our work provides the beginnings of the definition of a minimal contraction-competent cytokinetic ring apparatus.

S.M.P. SEQUENTIAL MATHEMATICS PROGRAM.

ERIC Educational Resources Information Center

CICIARELLI, V; LEONARD, JOSEPH

A SEQUENTIAL MATHEMATICS PROGRAM BEGINNING WITH THE BASIC FUNDAMENTALS ON THE FOURTH GRADE LEVEL IS PRESENTED. INCLUDED ARE AN UNDERSTANDING OF OUR NUMBER SYSTEM, AND THE BASIC OPERATIONS OF WORKING WITH WHOLE NUMBERS--ADDITION, SUBTRACTION, MULTIPLICATION, AND DIVISION. COMMON FRACTIONS ARE TAUGHT IN THE FIFTH, SIXTH, AND SEVENTH GRADES. A…

77 FR 30047 - Notice of Opportunity for Public Comment on Surplus Property Release at Michael J Smith Field...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-21

... Comment on Surplus Property Release at Michael J Smith Field, Beaufort, NC AGENCY: Federal Aviation... J Smith Field, be used for aeronautical purposes. DATES: Comments must be received on or before June... property at the Michael J Smith Field. The property consists of one parcel located on the north side of...

Mechanical System Reliability and Cost Integration Using a Sequential Linear Approximation Method

NASA Technical Reports Server (NTRS)

Kowal, Michael T.

1997-01-01

The development of new products is dependent on product designs that incorporate high levels of reliability along with a design that meets predetermined levels of system cost. Additional constraints on the product include explicit and implicit performance requirements. Existing reliability and cost prediction methods result in no direct linkage between variables affecting these two dominant product attributes. A methodology to integrate reliability and cost estimates using a sequential linear approximation method is proposed. The sequential linear approximation method utilizes probability of failure sensitivities determined from probabilistic reliability methods as well a manufacturing cost sensitivities. The application of the sequential linear approximation method to a mechanical system is demonstrated.

Design and Development of Sequential Rotary Valve

NASA Technical Reports Server (NTRS)

D’Orsi, Nicholas; Castillo, Priscilla

2017-01-01

Valves are used to regulate the flow of fluids through systems. This rotary valve's main purpose is to fill, pressurize, empty, and vent three smaller tanks with the supply of one larger tank. Many different designs are being taken into consideration, which are each at different stages of development. The furthest along uses three ball valves on a common shaft to open and close their respective ports as the shaft completes one full rotation or cycle. We were tasked with advancing this design to its first test as a plastic model for flow verification, as well as sizing and ordering the necessary O-rings and fasteners. A motor will also be sized to satisfy the torque requirements, and will then be programmed using a Raspberry Pi to rotate the shaft at the calculated speed and dwelling times needed to fill each tank equally. In addition, we have also been advancing designs that use a camshaft and poppets. These are earlier on in their development, currently being sized to replicate the expected flow patterns of the rotary ball valve. Expected outcomes of this valve include bi-directionality, successful sealing under pressure, and accurate cycling.

Daniel Sennert, The Philosophical Hen, and The Epistolary Quest for a (Nearly-) Universal Medicine.

PubMed

Klein, Joel A

2015-02-01

This article explores the Wittenberg Professor Daniel Sennert's (1572-1637) pursuit of nearly universal medicines made from noble metals, which he described in his published works and in private correspondence with his brother-in-law, Michael Döring. Of the medicaments that Sennert sought, one called the Philosophical Hen was especially interesting, and involved feeding a hen silver or gold during propitious astrological conjunctions. Sennert's support of this experiment was rooted in his obsession with experience and can be partially explained by looking to an extensive tradition of natural philosophy and natural history. Sennert explained such nearly universal medicines according to the rational principles of academic medicine, arguing that they strengthened the body's innate heat or acted as universal purgatives. From Sennert's candid epistles, we receive a more historicised portrait of the collaborative experimental process by which chymical medicines were conceptualised and tested, and how the consequences of experimental failure and perceived credulity could be increased scepticism.

E3 ligase Hei10: a multifaceted structure-based signaling molecule with roles within and beyond meiosis

PubMed Central

De Muyt, Arnaud; Zhang, Liangran; Piolot, Tristan; Kleckner, Nancy; Espagne, Eric; Zickler, Denise

2014-01-01

Human enhancer of invasion-10 (Hei10) mediates meiotic recombination and also plays roles in cell proliferation. Here we explore Hei10’s roles throughout the sexual cycle of the fungus Sordaria with respect to localization and effects of null, RING-binding, and putative cyclin-binding (RXL) domain mutations. Hei10 makes three successive types of foci. Early foci form along synaptonemal complex (SC) central regions. At some of these positions, depending on its RING and RXL domains, Hei10 mediates development and turnover of two sequential types of recombination complexes, each demarked by characteristic amplified Hei10 foci. Integration with ultrastructural data for recombination nodules further reveals that recombination complexes differentiate into three types, one of which corresponds to crossover recombination events during or prior to SC formation. Finally, Hei10 positively and negatively modulates SUMO localization along SCs by its RING and RXL domains, respectively. The presented findings suggest that Hei10 integrates signals from the SC, associated recombination complexes, and the cell cycle to mediate both the development and programmed turnover/evolution of recombination complexes via SUMOylation/ubiquitination. Analogous cell cycle-linked assembly/disassembly switching could underlie localization and roles for Hei10 in centrosome/spindle pole body dynamics and associated nuclear trafficking. We suggest that Hei10 is a unique type of structure-based signal transduction protein. PMID:24831702

Banana leaf and glucose mineralization and soil organic matter in microhabitats of banana plantations under long-term pesticide use.

PubMed

Blume, Elena; Reichert, José Miguel

2015-06-01

Soil organic matter (SOM) and microbial activity are key components of soil quality and sustainability. In the humid tropics of Costa Rica 3 pesticide regimes were studied-fungicide (low input); fungicide and herbicide (medium input); and fungicide, herbicide, and nematicide (high input)-under continuous banana cultivation for 5 yr (young) or 20 yr (old) in 3 microhabitats-nematicide ring around plants, litter pile of harvested banana, and bare area between litter pile and nematicide ring. Soil samples were incubated sequentially in the laboratory: unamended, amended with glucose, and amended with ground banana leaves. Soil organic matter varied with microhabitat, being greatest in the litter pile, where microbes had the greatest basal respiration with ground banana leaf, whereas microbes in the nematicide ring had the greatest respiration with glucose. These results suggest that soil microbes adapt to specific microhabitats. Young banana plantations had similar SOM compared with old plantations, but the former had greater basal microbial respiration in unamended and in glucose-amended soil and greater first-order mineralization rates in glucose-amended soil, thus indicating soil biological quality decline over time. High pesticide input did not decrease microbial activity or mineralization rate in surface soil. In conclusion, microbial activity in tropical volcanic soil is highly adaptable to organic and inorganic inputs. © 2015 SETAC.

Analysis of Optimal Sequential State Discrimination for Linearly Independent Pure Quantum States.

PubMed

Namkung, Min; Kwon, Younghun

2018-04-25

Recently, J. A. Bergou et al. proposed sequential state discrimination as a new quantum state discrimination scheme. In the scheme, by the successful sequential discrimination of a qubit state, receivers Bob and Charlie can share the information of the qubit prepared by a sender Alice. A merit of the scheme is that a quantum channel is established between Bob and Charlie, but a classical communication is not allowed. In this report, we present a method for extending the original sequential state discrimination of two qubit states to a scheme of N linearly independent pure quantum states. Specifically, we obtain the conditions for the sequential state discrimination of N = 3 pure quantum states. We can analytically provide conditions when there is a special symmetry among N = 3 linearly independent pure quantum states. Additionally, we show that the scenario proposed in this study can be applied to quantum key distribution. Furthermore, we show that the sequential state discrimination of three qutrit states performs better than the strategy of probabilistic quantum cloning.

Morphological evolution of Ge/Si(001) quantum dot rings formed at the rim of wet-etched pits.

PubMed

Grydlik, Martyna; Brehm, Moritz; Schäffler, Friedrich

2012-10-30

We demonstrate the formation of Ge quantum dots in ring-like arrangements around predefined {111}-faceted pits in the Si(001) substrate. We report on the complex morphological evolution of the single quantum dots contributing to the rings by means of atomic force microscopy and demonstrate that by careful adjustment of the epitaxial growth parameters, such rings containing densely squeezed islands can be grown with large spatial distances of up to 5 μm without additional nucleation of randomly distributed quantum dots between the rings.

Metal-mediated aminocatalysis provides mild conditions: Enantioselective Michael addition mediated by primary amino catalysts and alkali-metal ions

PubMed Central

Leven, Matthias; Neudörfl, Jörg M

2013-01-01

Summary Four catalysts based on new amides of chiral 1,2-diamines and 2-sulfobenzoic acid have been developed. The alkali-metal salts of these betaine-like amides are able to form imines with enones, which are activated by Lewis acid interaction for nucleophilic attack by 4-hydroxycoumarin. The addition of 4-hydroxycoumarin to enones gives ee’s up to 83% and almost quantitative yields in many cases. This novel type of catalysis provides an effective alternative to conventional primary amino catalysis were strong acid additives are essential components. PMID:23400419

Synthesis and Characterization of 9-Hydroxyphenalenone Using 2D NMR Techniques

ERIC Educational Resources Information Center

Caes, Benjamin; Jensen, Dell, Jr.

2008-01-01

9-Hydroxyphenalenone is a planar multicyclic [beta]-keto-enol, which is synthesized via a Friedel-Crafts acylation followed by acid-catalyzed intramolecular Michael addition with the loss of a phenyl group in a one-pot reaction during a four-hour lab period. Tautomerization of the [beta]-keto-enol results in C[subscript 2v] symmetry on the NMR…

Cell protein cross-linking by erbstatin and related compounds | Center for Cancer Research

Cancer.gov

The scheme depicts a possible mechanism of cross-linking by erbstatin and related analogues. A mechanism of action is proposed which involves initial oxidation to reactive quinone intermediates that subsequently cross-link protein nucleophiles via multiple 1,4-Michael-type additions. Similar alkylation of protein by protein-tyrosine kinase inhibitors, such as herbimycin A, has

Crisis -- A Leadership Opportunity

DTIC Science & Technology

2005-04-01

recognized the great value in understanding crisis theory and the leadership strategies to employ during these situations. Additionally, we discovered...ed.: 50. Mitroff, Ian I. Crisis leadership : Planning for the Unthinkable. Hoboken: Wiley, 2004. Murphy, P. (1996). "Chaos Theory as a Model...Crisis–A Leadership Opportunity COL Victor Braden, ARNG CAPT Justin Cooper II, USN COL Michael Klingele, USA Lt Col John P

CSP - Hyperspectral Imaging and Sounding of the Environment Meeting Scholarship Fund

DTIC Science & Technology

2017-05-09

performance via adaptation to the environment. The meeting has also contributed to the focus area of Electromagnetic Maneuver Warfare through disseminating the...latest information about advanced sensing techniques and understanding the electromagnetic environment through sensing. Additional sessions on...across the electromagnetic spectrum. The attendees at this event from the Naval Research Enterprise were Dr. Michael Yetzbacher, as a Program Co

Ion-Molecule Association in Acrylonitrile

NASA Technical Reports Server (NTRS)

Wilson, Paul F.; Milligan, Daniel B.; McEwan, Murray J.

1997-01-01

Acrylonitrile (propernenitrile or vinyl cyanide) polymerizes readily via a radical mechanism in solution at room temparature. The propensity to polymerize is sufficiently strong that it is usual to add a radical scavenger to the solution to prevent polymerization when oxygen (an inhibitor) is removed. Polymerization of acrylonitrile is also know to occur via nucleophilic addition of an anion by a michael-type reaction.

"Fahrenheit 9-11," Need for Closure and the Priming of Affective Ambivalence: An Assessment of Intra-Affective Structures by Party Identification

ERIC Educational Resources Information Center

Holbert, R. Lance; Hansen, Glenn J.

2006-01-01

This study extends priming research in political communication by focusing on an alternative political information source (i.e., Michael Moore's Fahrenheit 9-11), affect rather than cognitions, and the existence of intra-affective ambivalence. In addition, two moderator variables are analyzed: political party identification and need for closure.…

Molecular Characterization of Thiols in Fossil Fuels by Michael Addition Reaction Derivatization and Electrospray Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry.

PubMed

Wang, Meng; Zhao, Suoqi; Liu, Xuxia; Shi, Quan

2016-10-04

Thiols widely occur in sediments and fossil fuels. However, the molecular composition of these compounds is unclear due to the lack of appropriate analytical methods. In this work, a characterization method for thiols in fossil fuels was developed on the basis of Michael addition reaction derivatization followed by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS). Model thiol compound studies showed that thiols were selectively reacted with phenylvinylsulfone and transformed to sulfones with greater than 98% conversions. This method was applied to a coker naphtha, light and heavy gas oils, and crude oils from various geological sources. The results showed that long alkyl chain thiols are readily present in petroleum, which have up to 30 carbon atoms. Large DBE dispersity of thiols indicates that naphthenic and aromatic thiols are also present in the petroleum. This method is capable of detecting thiol compounds in the part per million range by weight. This method allows characterization of thiols in a complex hydrocarbon matrix, which is complementary to the comprehensive analysis of sulfur compounds in fossil fuels.

Preparation of amine functionalized carbon nanotubes via a bioinspired strategy and their application in Cu2+ removal

NASA Astrophysics Data System (ADS)

Zhang, Xiaoyong; Huang, Qiang; Liu, Meiying; Tian, Jianwen; Zeng, Guangjian; Li, Zhen; Wang, Ke; Zhang, Qinsong; Wan, Qing; Deng, Fengjie; Wei, Yen

2015-07-01

The environmental applications of carbon nanotubes (CNTs) have attracted great research attention since their first discovery. However, the performance of pristine CNTs for removal of heavy metal ions is greatly limited by their severe aggregation and lack of functional groups. In this work, a novel method has been developed for preparation of amine functionalized CNTs via combination of mussel inspired chemistry and Michael addition reaction. CNTs were first coated with polydopamine (PDA) through mussel inspired chemistry. And then commercial available agent polyethylene polyamine with a number of amine groups was further conjugated with PDA coated CNTs via Michael addition reaction. A series of characterization techniques have demonstrated that the amine functionalized CNTs have been successfully prepared. Furthermore, the adsorption application of thus amine functionalized CNTs for Cu2+ was examined. The effects of various parameters including pH solution, temperature, initial Cu2+ concentration and the adsorbent concentration were investigated. The data from experiments were analyzed by the Langmuir and Freundlich models of adsorption. Due to the universal of mussel inspired chemistry, the method described in this work should be a general strategy for surface modification of materials for environmental applications.

Saturn's E, G, and F rings - Modulated by the plasma sheet?

NASA Technical Reports Server (NTRS)

Morfill, G. E.; Gruen, E.; Johnson, T. V.

1983-01-01

Saturn's broad E ring, the narrow G ring, and the structured and apparently time-variable F ring(s) contain many micron and submicron-sized particles, which make up the 'visible' component. These rings (or ring systems) are in direct contact with magnetospheric plasma. Fluctuations in the plasma density and/or mean energy, due to magnetospheric and solar wind processes, may induce stochastic charge variations on the dust particles, which in turn lead to an orbit perturbation and spatial diffusion. In addition, Coulomb drag forces may be important, in particular for the E ring. The possibility that electromagnetic effects may play a role in determining the F ring structure and its possible time variations is critically examined. Sputtering of micron-sized dust particles in the E ring by magnetospheric ions yields lifetimes of 100 to 10,000 years. This effect as well as the plasma induced transport processes require an active source for the E ring, probably Enceladus.

46 CFR 169.549 - Ring lifebuoys and water lights.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 7 2011-10-01 2011-10-01 false Ring lifebuoys and water lights. 169.549 Section 169.549 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Lifesaving and Firefighting Equipment Additional Lifesaving Equipment § 169.549 Ring lifebuoys and water lights. (a)(1) The minimum number of...

46 CFR 169.549 - Ring lifebuoys and water lights.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 7 2010-10-01 2010-10-01 false Ring lifebuoys and water lights. 169.549 Section 169.549 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Lifesaving and Firefighting Equipment Additional Lifesaving Equipment § 169.549 Ring lifebuoys and water lights. (a)(1) The minimum number of...

46 CFR 169.549 - Ring lifebuoys and water lights.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 7 2013-10-01 2013-10-01 false Ring lifebuoys and water lights. 169.549 Section 169.549 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Lifesaving and Firefighting Equipment Additional Lifesaving Equipment § 169.549 Ring lifebuoys and water lights. (a)(1) The minimum number of...

DefenseLink Feature: Chairman Visits Japan and Republic of Korea, Nov. 5-8,

Science.gov Websites

Staff Navy Adm. Michael G. Mullen answers questions at a press availability with local media following Staff Navy Adm. Michael G. Mullen visits greets marines and staff assigned to the U.S. Embassy, Tokyo the Joint Chiefs of Staff U.S. Navy Adm. Michael G. Mullen, right, and Japanese Chief of Defense Adm

Dipolar-dephasing 13C NMR studies of decomposed wood and coalified xylem tissue: Evidence for chemical structural changes associated with defunctionalization of lignin structural units during coalification

USGS Publications Warehouse

Hatcher, P.G.

1988-01-01

A series of decomposed and coalified gymnosperm woods was examined by conventional solid-state 13C nuclear magnetic resonance (NMR) and by dipolar-dephasing NMR techniques. The results of these NMR studies for a histologically related series of samples provide clues as to the nature of codification reactions that lead to the defunctionalization of lignin-derived aromatic structures. These reactions sequentially involve the following: (1) loss of methoxyl carbons from guaiacyl structural units with replacement by hydroxyls and increased condensation; (2) loss of hydroxyls or aryl ethers with replacement by hydrogen as rank increases from lignin to high-volatile bituminous coal; (3) loss of alkyl groups with continued replacement by hydrogen. The dipolar-dephasing data show that the early stages of coalification in samples examined (lignin to lignite) involve a decreasing degree of protonation on aromatic rings and suggest that condensation is significant during coalification at this early stage. An increasing degree of protonation on aromatic rings is observed as the rank of the sample increases from lignite to anthracite.

Poor Performance on Serial Visual Tasks in Persons with Reading Disabilities: Impaired Working Memory?

ERIC Educational Resources Information Center

Ram-Tsur, Ronit; Faust, Miriam; Zivotofsky, Ari Z.

2008-01-01

The present study investigates the performance of persons with reading disabilities (PRD) on a variety of sequential visual-comparison tasks that have different working-memory requirements. In addition, mediating relationships between the sequential comparison process and attention and memory skills were looked for. Our findings suggest that PRD…

Test pattern generation for ILA sequential circuits

NASA Technical Reports Server (NTRS)

Feng, YU; Frenzel, James F.; Maki, Gary K.

1993-01-01

An efficient method of generating test patterns for sequential machines implemented using one-dimensional, unilateral, iterative logic arrays (ILA's) of BTS pass transistor networks is presented. Based on a transistor level fault model, the method affords a unique opportunity for real-time fault detection with improved fault coverage. The resulting test sets are shown to be equivalent to those obtained using conventional gate level models, thus eliminating the need for additional test patterns. The proposed method advances the simplicity and ease of the test pattern generation for a special class of sequential circuitry.

Group-sequential three-arm noninferiority clinical trial designs

PubMed Central

Ochiai, Toshimitsu; Hamasaki, Toshimitsu; Evans, Scott R.; Asakura, Koko; Ohno, Yuko

2016-01-01

We discuss group-sequential three-arm noninferiority clinical trial designs that include active and placebo controls for evaluating both assay sensitivity and noninferiority. We extend two existing approaches, the fixed margin and fraction approaches, into a group-sequential setting with two decision-making frameworks. We investigate the operating characteristics including power, Type I error rate, maximum and expected sample sizes, as design factors vary. In addition, we discuss sample size recalculation and its’ impact on the power and Type I error rate via a simulation study. PMID:26892481

A cost and policy analysis comparing immediate sequential cataract surgery and delayed sequential cataract surgery from the physician perspective in the United States.

PubMed

Neel, Sean T

2014-11-01

A cost analysis was performed to evaluate the effect on physicians in the United States of a transition from delayed sequential cataract surgery to immediate sequential cataract surgery. Financial and efficiency impacts of this change were evaluated to determine whether efficiency gains could offset potential reduced revenue. A cost analysis using Medicare cataract surgery volume estimates, Medicare 2012 physician cataract surgery reimbursement schedules, and estimates of potential additional office visit revenue comparing immediate sequential cataract surgery with delayed sequential cataract surgery for a single specialty ophthalmology practice in West Tennessee. This model should give an indication of the effect on physicians on a national basis. A single specialty ophthalmology practice in West Tennessee was found to have a cataract surgery revenue loss of $126,000, increased revenue from office visits of $34,449 to $106,271 (minimum and maximum offset methods), and a net loss of $19,900 to $91,700 (base case) with the conversion to immediate sequential cataract surgery. Physicians likely stand to lose financially, and this loss cannot be offset by increased patient visits under the current reimbursement system. This may result in physician resistance to converting to immediate sequential cataract surgery, gaming, and supplier-induced demand.

Sequential biases in accumulating evidence

PubMed Central

Huggins, Richard; Dogo, Samson Henry

2015-01-01

Whilst it is common in clinical trials to use the results of tests at one phase to decide whether to continue to the next phase and to subsequently design the next phase, we show that this can lead to biased results in evidence synthesis. Two new kinds of bias associated with accumulating evidence, termed ‘sequential decision bias’ and ‘sequential design bias’, are identified. Both kinds of bias are the result of making decisions on the usefulness of a new study, or its design, based on the previous studies. Sequential decision bias is determined by the correlation between the value of the current estimated effect and the probability of conducting an additional study. Sequential design bias arises from using the estimated value instead of the clinically relevant value of an effect in sample size calculations. We considered both the fixed‐effect and the random‐effects models of meta‐analysis and demonstrated analytically and by simulations that in both settings the problems due to sequential biases are apparent. According to our simulations, the sequential biases increase with increased heterogeneity. Minimisation of sequential biases arises as a new and important research area necessary for successful evidence‐based approaches to the development of science. © 2015 The Authors. Research Synthesis Methods Published by John Wiley & Sons Ltd. PMID:26626562

Reaction Mechanism of Organocatalytic Michael Addition of Nitromethane to Cinnamaldehyde: A Case Study on Catalyst Regeneration and Solvent Effects.

PubMed

Świderek, Katarzyna; Nödling, Alexander R; Tsai, Yu-Hsuan; Luk, Louis Y P; Moliner, Vicent

2018-01-11

The Michael addition of nitromethane to cinnamaldehyde has been computationally studied in the absence of a catalyst and the presence of a biotinylated secondary amine by a combined computational and experimental approach. The calculations were performed at the density functional theory (DFT) level with the M06-2X hybrid functional, and a polarizable continuum model has been employed to mimic the effect of two different solvents: dichloromethane (DCM) and water. Contrary to common assumption, the product-derived iminium intermediate was absent in both of the solvents tested. Instead, hydrating the C1-C2 double bond in the enamine intermediate directly yields the tetrahedral intermediate, which is key for forming the product and regenerating the catalyst. Enamine hydration is concerted and found to be rate-limiting in DCM but segregated into two non-rate-limiting steps when the solvent is replaced with water. However, further analysis revealed that the use of water as solvent also raises the energy barriers for other chemical steps, particularly the critical step of C-C bond formation between the iminium intermediate and nucleophile; this consequently lowers both the reaction yield and enantioselectivity of this LUMO-lowering reaction, as experimentally detected. These findings provide a logical explanation to why water often enhances organocatalysis when used as an additive but hampers the reaction progress when employed as a solvent.

Reaction Mechanism of Organocatalytic Michael Addition of Nitromethane to Cinnamaldehyde: A Case Study on Catalyst Regeneration and Solvent Effects

PubMed Central

2017-01-01

The Michael addition of nitromethane to cinnamaldehyde has been computationally studied in the absence of a catalyst and the presence of a biotinylated secondary amine by a combined computational and experimental approach. The calculations were performed at the density functional theory (DFT) level with the M06-2X hybrid functional, and a polarizable continuum model has been employed to mimic the effect of two different solvents: dichloromethane (DCM) and water. Contrary to common assumption, the product-derived iminium intermediate was absent in both of the solvents tested. Instead, hydrating the C1–C2 double bond in the enamine intermediate directly yields the tetrahedral intermediate, which is key for forming the product and regenerating the catalyst. Enamine hydration is concerted and found to be rate-limiting in DCM but segregated into two non-rate-limiting steps when the solvent is replaced with water. However, further analysis revealed that the use of water as solvent also raises the energy barriers for other chemical steps, particularly the critical step of C–C bond formation between the iminium intermediate and nucleophile; this consequently lowers both the reaction yield and enantioselectivity of this LUMO-lowering reaction, as experimentally detected. These findings provide a logical explanation to why water often enhances organocatalysis when used as an additive but hampers the reaction progress when employed as a solvent. PMID:29256614

Saturn Ring-Plane Crossing, may 1995

NASA Astrophysics Data System (ADS)

Bosh, Amanda

1995-07-01

In 1995-1996, the Earth and the Sun will pass through Saturn's ring plane. The Earth will pass through 3 times (22 May 1995, 10 August 1995, 11 Feb 1996), and the Sun will pass through once (19 November 1995). All but the 11 Feb 1996 event will be visible from HST. During the crossings of the Earth through Saturn's ring plane, the rings will become very thin and dark. By monitoring the brightness of the rings as they become very thin, we will be able to determine the time of ring-plane crossing and the residual brightness of the rings at this time. The time of the ring- plane crossing will place additional constraints on the precession rate of Saturn's pole. The recent occultations by Saturn's rings have produced a measurement of this value, but it is not known very well (French et al., 1993; Bosh, 1994; Elliot et al., 1993). A measure of the brightness of the rings in their edge-on configuration, combined with photometric properties of the rings derived from early calibration observations will allow us to determine the thickness of the rings.

Stable forming conditions and geometrical expansion of L-shape rings in ring rolling process

NASA Astrophysics Data System (ADS)

Quagliato, Luca; Berti, Guido A.; Kim, Dongwook; Kim, Naksoo

2018-05-01

Based on previous research results concerning the radial-axial ring rolling process of flat rings, this paper details an innovative approach for the determination of the stable forming conditions to successfully simulate the radial ring rolling process of L-shape profiled rings. In addition to that, an analytical model for the estimation of the geometrical expansion of L-shape rings from its initial flat ring preform is proposed and validated by comparing its results with those of numerical simulations. By utilizing the proposed approach, steady forming conditions could be achieved, granting a uniform expansion of the ring throughout the process for all of the six tested cases of rings having the final outer diameter of the flange ranging from 545mm and 1440mm. The validation of the proposed approach allowed concluding that the geometrical expansion of the ring, as estimated by the proposed analytical model, is in good agreement with the results of the numerical simulation, with a maximum error of 2.18%, in the estimation of the ring wall diameter, 1.42% of the ring flange diameter and 1.87% for the estimation of the inner diameter of the ring, respectively.

Gnostic rings: usefulness in sensibility evaluation and sensory reeducation.

PubMed

Brunelli, G; Battiston, B; Dellon, A L

1992-01-01

The benefit of additional clinical tools for quantifying patients' ability to recognize objects is clear, as well as its correlation with the moving two-point discrimination test. The recognition of letters is such a tool. The authors describe gnostic rings, an additional technique, that is useful for clinical sensibility testing, as well as for sensory reeducation.

Field enhanced graphene based dual hexagonal ring optical antenna for tip-enhanced spectroscopy

NASA Astrophysics Data System (ADS)

Aditya, Rachakonda A. N. S.; Thampy, Anand Sreekantan

2018-05-01

Field enhanced graphene based dual hexagonal ring optical antenna has been designed in IR regime. Outcomes of hexagonal rings with gold and graphene materials and their effect has been studied and analyzed. Graphene based structures are found to have better and enhanced results as compared to that of gold. In addition, a two fold increase in bandwidth (∼30 THz) and cross-section (∼6.00E+06 nm2) has been observed in case of graphene. Field patterns for various tip/corner curvatures are simulated and localized/regional field patterns are justified. The effect of inter ring spacing on absorption cross section has been studied for every 10 nm increase in spacing. This absorption enhancement in addition to field localization makes the current structure feasible for tip enhanced spectroscopy.

Versatile telluracycle synthesis via the sequential electrophilic telluration of C(sp2)–Zn and C(sp2)–H bonds† †Electronic supplementary information (ESI) available. CCDC 1523262–1523264. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c7sc01162h Click here for additional data file. Click here for additional data file.

PubMed Central

Wu, Bin; Melvina; Wu, Xiangyang; Lee Yeow, Edwin Kok

2017-01-01

We report herein a new approach for the synthesis of tellurium-bridged aromatic compounds based on the sequential electrophilic telluration of C(sp2)–Zn and C(sp2)–H bonds with tellurium(iv) chlorides. A combination of transition metal-catalyzed (migratory) arylmetalation of alkynes and sequential telluration allows for the expedient construction of a library of functionalized benzo[b]tellurophenes. Furthermore, a variety of heteroarene-fused benzotellurophenes and other novel tellurium-embedded polycyclic aromatics can be readily synthesized from the corresponding 2-iodoheterobiaryls. PMID:28970880

Strategic Studies Quarterly. Volume 8, Number 3, Fall 2014

DTIC Science & Technology

2014-01-01

Michael Guillot Measuring Military Power James Jay Carafano Strategy and Force Planning in a Time of Austerity BG Michael J . Meese, USA, Retired...Hudson, PhD Nori Katagiri, PhD Paul J . Springer, PhD Zachary J . Zwald, PhD Strategic Studies Quarterly (SSQ) (ISSN 1936-1815) is published quarterly...19 BG Michael J . Meese, USA, Retired Pensive Sword: Educating Officers in Austere Times ...................... 30 Stephen D. Chiabotti Feature

DefenseLink.mil - Pentagon Memorial Dedication

Science.gov Websites

Dept. photo by Army Staff Sgt. Michael J. Carden An entry stone at the Pentagon Memorial lists the their lives during the Sept. 11 terrorist attack on the Pentagon. Photo by Staff Sgt. Michael J. Carden Staff Sgt. Michael J. Carden A member of The United States Air Force Band practices before the start of

Hearts-and-Minds: A Strategy of Conciliation, Coercion, or Commitment?

DTIC Science & Technology

2012-09-01

benefits to modern conflicts remains problematic. According to Colonel (retired) Michael Crawshaw writing on evolution of British COIN for the United...Richmond, UK: Curzon Press, 2002), 11. 9. Michael Crawshaw , “The Evolution of British COIN,” Se- curity and Stabilisation: The Military Contribution...Afghanistan” (Cahier de la Recherche, France: November 2011), 42. 12. Ibid., 43. 13. Michael Crawshaw , “The Evolution of British COIN,” Se- curity and

Development and Implementation of an Interactive Uniform Regulations Manual for the United States Marine Corps

DTIC Science & Technology

2006-09-01

IMPLEMENTATION OF AN INTERACTIVE UNIFORM REGULATIONS MANUAL FOR THE UNITED STATES MARINE CORPS by Michael H. Villar Carsten Krause...SUBTITLE: Development and Implementation of an Interactive Uniform Regulations Manual for the United States Marine Corps 6. AUTHOR(S) Michael H. Villar...IMPLEMENTATION OF AN INTERACTIVE UNIFORM REGULATIONS MANUAL FOR THE UNITED STATES MARINE CORPS Michael H. Villar Major, United States Marine Corps B.A

Understanding a Complex World: Why an Emphasis on Empathy Could Better Enable Army Leaders to Win

DTIC Science & Technology

2016-06-10

complexity and speed of human interactions. Through the analysis of case studies involving General Stanley McChrystal and Colonel Michael Steele , this...Future; Win; Dilemma; Leadership; McChrystal, Stanley; Steele , Michael 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT 18. NUMBER OF...Stanley McChrystal and Colonel Michael Steele , this thesis describes how each individual’s empathetic mindset resulted in both favorable and

Combat Service Support MOD II Design (CSS MOD II). Volume 2. Appendixes

DTIC Science & Technology

1986-10-01

through contractual aoreement with Michael Jackson , Ltd. London. The spelling, syntax, and word usage adopted throughout the document have been made...to conform to army standards. The design teas members wish to thank the followin, individuals for their assistances Mr. John Cameron, Michael Jackson , Ltd...JSP) methodology is a product of Michael Jackson Systems, Ltd., London, England. In 1984, Dr. Wilbur Payne, Director, TRADOC Operations Research

Psychological Analyses of Courageous Performance in Military Personnel

DTIC Science & Technology

1990-08-01

British Columbia ARI Scientific Coordination Office, London Milton Katz, Chief Office of Basic Research Michael Kaplan , Director OTIC August1990 ELECTE...For NTIS Ri University of British Columbia DTic TAB Just fitIcat lo Technical review by Dy __Dttibut ton/ Michael Kaplan Avallability CodesDIst...22c. OFFICE SYMBOL Michael Kaplan (202) 274-8722 PERT-BR DD Form 1473, JUN 86 Previous editions are obsolete. SECURITY CLASSIFICATION OF THIS PAGE

Development and Implementation of Low-Cost Mobile Sensor Platforms Within a Wireless Sensor Network

DTIC Science & Technology

2010-09-01

WIRELESS SENSOR NETWORK by Michael Jay Tozzi September 2010 Thesis Advisor: Rachel Goshorn Second Reader: Duane Davis Approved for...Platforms Within a Wireless Sensor Network 6. AUTHOR(S) Tozzi, Michael Jay 5. FUNDING NUMBERS 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Naval...IMPLEMENTATION OF LOW-COST MOBILE SENSOR PLATFORMS WITHIN A WIRELESS SENSOR NETWORK Michael Jay Tozzi Lieutenant, United States Navy B.S., United

Biomechanical Comparison of External Fixation and Compression Screws for Transverse Tarsal Joint Arthrodesis.

PubMed

Latt, L Daniel; Glisson, Richard R; Adams, Samuel B; Schuh, Reinhard; Narron, John A; Easley, Mark E

2015-10-01

Transverse tarsal joint arthrodesis is commonly performed in the operative treatment of hindfoot arthritis and acquired flatfoot deformity. While fixation is typically achieved using screws, failure to obtain and maintain joint compression sometimes occurs, potentially leading to nonunion. External fixation is an alternate method of achieving arthrodesis site compression and has the advantage of allowing postoperative compression adjustment when necessary. However, its performance relative to standard screw fixation has not been quantified in this application. We hypothesized that external fixation could provide transverse tarsal joint compression exceeding that possible with screw fixation. Transverse tarsal joint fixation was performed sequentially, first with a circular external fixator and then with compression screws, on 9 fresh-frozen cadaveric legs. The external fixator was attached in abutting rings fixed to the tibia and the hindfoot and a third anterior ring parallel to the hindfoot ring using transverse wires and half-pins in the tibial diaphysis, calcaneus, and metatarsals. Screw fixation comprised two 4.3 mm headless compression screws traversing the talonavicular joint and 1 across the calcaneocuboid joint. Compressive forces generated during incremental fixator foot ring displacement to 20 mm and incremental screw tightening were measured using a custom-fabricated instrumented miniature external fixator spanning the transverse tarsal joint. The maximum compressive force generated by the external fixator averaged 186% of that produced by the screws (range, 104%-391%). Fixator compression surpassed that obtainable with screws at 12 mm of ring displacement and decreased when the tibial ring was detached. No correlation was found between bone density and the compressive force achievable by either fusion method. The compression across the transverse tarsal joint that can be obtained with a circular external fixator including a tibial ring exceeds that which can be obtained with 3 headless compression screws. Screw and external fixator performance did not correlate with bone mineral density. This study supports the use of external fixation as an alternative method of generating compression to help stimulate fusion across the transverse tarsal joints. The findings provide biomechanical evidence to support the use of external fixation as a viable option in transverse tarsal joint fusion cases in which screw fixation has failed or is anticipated to be inadequate due to suboptimal bone quality. © The Author(s) 2015.

An Archetype Semi-Ring Fabry-Perot (SRFP) Resonator

NASA Technical Reports Server (NTRS)

Taghavi-Larigani, Shervin; VanZyl, Jakob

2009-01-01

We introduce and demonstrate the generation of a novel resonator, termed Semi-Ring Fabry-Perot (SRFP), that exhibits unique features, such as, its use of one plane mirror, allowing the SRFP to be easily fabricated as a symmetrical device. In addition to its unique features, it exhibits advantages of ring and Fabry-Perot resonators: 1) compared to a ring resonator that only allows a transmitted intensity, the Semi-Ring Fabry-Perot (SRFP) supports standing waves, allowing both a reflected and transmitted intensity; 2) the reflected light spectrum of the SRFP resonator is much narrower than similar Fabry-Perot, implying higher finesse.

PySeqLab: an open source Python package for sequence labeling and segmentation.

PubMed

Allam, Ahmed; Krauthammer, Michael

2017-11-01

Text and genomic data are composed of sequential tokens, such as words and nucleotides that give rise to higher order syntactic constructs. In this work, we aim at providing a comprehensive Python library implementing conditional random fields (CRFs), a class of probabilistic graphical models, for robust prediction of these constructs from sequential data. Python Sequence Labeling (PySeqLab) is an open source package for performing supervised learning in structured prediction tasks. It implements CRFs models, that is discriminative models from (i) first-order to higher-order linear-chain CRFs, and from (ii) first-order to higher-order semi-Markov CRFs (semi-CRFs). Moreover, it provides multiple learning algorithms for estimating model parameters such as (i) stochastic gradient descent (SGD) and its multiple variations, (ii) structured perceptron with multiple averaging schemes supporting exact and inexact search using 'violation-fixing' framework, (iii) search-based probabilistic online learning algorithm (SAPO) and (iv) an interface for Broyden-Fletcher-Goldfarb-Shanno (BFGS) and the limited-memory BFGS algorithms. Viterbi and Viterbi A* are used for inference and decoding of sequences. Using PySeqLab, we built models (classifiers) and evaluated their performance in three different domains: (i) biomedical Natural language processing (NLP), (ii) predictive DNA sequence analysis and (iii) Human activity recognition (HAR). State-of-the-art performance comparable to machine-learning based systems was achieved in the three domains without feature engineering or the use of knowledge sources. PySeqLab is available through https://bitbucket.org/A_2/pyseqlab with tutorials and documentation. ahmed.allam@yale.edu or michael.krauthammer@yale.edu. Supplementary data are available at Bioinformatics online. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com

Support System for Solar Receivers

NASA Technical Reports Server (NTRS)

Kiceniuk, T.

1985-01-01

Hinged split-ring mounts insure safe support of heavy receivers. In addition to safer operation and damage-free mounting system provides more accurate focusing, and small incremental adjustments of ring more easily made.

Application of cyclic phosphonamide reagents in the total synthesis of natural products and biologically active molecules

PubMed Central

Focken, Thilo

2014-01-01

Summary A review of the synthesis of natural products and bioactive compounds adopting phosphonamide anion technology is presented highlighting the utility of phosphonamide reagents in stereocontrolled bond-forming reactions. Methodologies utilizing phosphonamide anions in asymmetric alkylations, Michael additions, olefinations, and cyclopropanations will be summarized, as well as an overview of the synthesis of the employed phosphonamide reagents. PMID:25246946

A chromenoquinoline-based fluorescent off-on thiol probe for bioimaging.

PubMed

Kand, Dnyaneshwar; Kalle, Arunasree Marasanapalli; Varma, Sreejith Jayasree; Talukdar, Pinaki

2012-03-11

A new chromenoquinoline-based fluorescent off-on thiol probe 2 is reported. In aqueous buffer solutions at physiological pH, the probe exhibited 223-fold enhancement in fluorescence intensity by a Michael addition of cysteine to the maleimide appended to a chromenoquinoline. Cell permeability and live cell imaging of thiols are also demonstrated. This journal is © The Royal Society of Chemistry 2012

Summer Prostate Cancer Research Training Program

DTIC Science & Technology

2017-09-01

Biology, and Human Toxicology Graduate Programs. Michael Henry, PhD; Associate Professor, Department of Physiology & Biophysics (319-335- 7886) http...addition, PSA has also been demonstrated to be antigenic and capable of inducing specific immune responses in both humans and mice. However, up to...for animal immunization. Both BCG and Ad microbes have been demonstrated to be safe and effective for antigen delivery in humans and mice. Since

Global Military Operating Environments (GMOE) Phase I: Linking Natural Environments, International Security, and Military Operations

DTIC Science & Technology

2013-01-30

example from the Negev Desert, Israel, Journal of Geophysical Research, (05 2009): 1. doi: 01/14/2013 5.00 Michael Young, Eric McDonald, Jianting Zhu... radiation (incoming – reflected) x Solar Radiation Eppley Incoming solar radiation x Surface temperature IR Apogee Continuous surface...and electrical properties (dielectric permittivity and electrical conductivity). Additional measurements of solar radiation (four components), air

Thiourea in the Construction of C-S Bonds as Part of an Undergraduate Organic Chemistry Laboratory Course

ERIC Educational Resources Information Center

Lu, Guo-ping; Chen, Fei; Cai, Chun

2017-01-01

The nucleophilic aromatic substitution reaction and thia-Michael addition using thiourea as an odorless, cheap, and easy-to-handle sulfur source in water are described, which can be used to teach upper-division undergraduates the role of thiourea in the formation of C-S bonds and the principles of green chemistry. The use of a cheap, nontoxic…

Dynamics of planetary rings

NASA Technical Reports Server (NTRS)

Araki, Suguru

1991-01-01

The modeling of the dynamics of particle collisions within planetary rings is discussed. Particles in the rings collide with one another because they have small random motions in addition to their orbital velocity. The orbital speed is roughly 10 km/s, while the random motions have an average speed of about a tenth of a millimeter per second. As a result, the particle collisions are very gentle. Numerical analysis and simulation of the ring dynamics, performed with the aid of a supercomputer, is outlined.

Using multi-ring structure for suppression of mode competition in stable single-longitudinal-mode erbium fiber laser

NASA Astrophysics Data System (ADS)

Yeh, Chien-Hung; Huang, Tzu-Jung; Yang, Zi-Qing; Chow, Chi-Wai

2017-12-01

In this demonstration, a stable and tunable single-longitudinal-mode (SLM) erbium-doped fiber (EDF) laser with multiple-ring configuration is proposed and investigated. The proposed compound-ring structure can create different free spectrum ranges (FSRs) to result in the mode-filter effect based on the Vernier effect for suppressing the other modes. Additionally, the output stabilization of power and wavelength in the proposed EDF multiple-ring laser are also discussed.

Exploring Liquid Sequential Injection Chromatography to Teach Fundamentals of Separation Methods: A Very Fast Analytical Chemistry Experiment

ERIC Educational Resources Information Center

Penteado, Jose C.; Masini, Jorge Cesar

2011-01-01

Influence of the solvent strength determined by the addition of a mobile-phase organic modifier and pH on chromatographic separation of sorbic acid and vanillin has been investigated by the relatively new technique, liquid sequential injection chromatography (SIC). This technique uses reversed-phase monolithic stationary phase to execute fast…

Sequential Organization and Room Reverberation for Speech Segregation

DTIC Science & Technology

2012-02-28

we have proposed two algorithms for sequential organization, an unsupervised clustering algorithm applicable to monaural recordings and a binaural ...algorithm that integrates monaural and binaural analyses. In addition, we have conducted speech intelligibility tests that Firmly establish the...comprehensive version is currently under review for journal publication. A binaural approach in room reverberation Most existing approaches to binaural or

Unconventional Counterinsurgency: Leveraging Traditional Social Networks and Irregular Forces in Remote and Ungoverned Areas

DTIC Science & Technology

2010-05-13

Identity: Why We Are Losing Our Wars”, Michael Vlahos argues that today’s wars with non-state enemies are “above all, wars of identity.”29 Moreover, he...together these manuals powerfully reinforce Michael Vlahos ’ imperative to reshape the population and enemy narrative by co-opting identity.34...29 Michael Vlahos , "Fighting Identity: Why We Are Losing Our Wars," Military Review (United States

Topological Privacy: Lattice Structures and Information Bubbles for Inference and Obfuscation

DTIC Science & Technology

2016-12-19

AFRL-AFOSR-VA-TR-2017-0036 Topological Privacy Michael Erdmann CARNEGIE MELLON UNIVERSITY 5000 FORBES AVENUE PITTSBURGH, PA 15213-3815 02/22/2017...PERSON 19b. TELEPHONE NUMBER (Include area code) 19-12-2016 Final 15-10-2013 - 14-10-2016 Topological Privacy Erdmann, Michael, A. Carnegie Mellon...Michael Erdmann Carnegie Mellon University me@cs.cmu.edu December 19, 2016 Abstract Information has intrinsic geometric and topological structure, arising

Description and Evaluation of GDEM-V 3.0

DTIC Science & Technology

2009-02-06

Description and Evaluation of GDEM -V 3.0 Michael R. caRnes Ocean Sciences Branch Oceanography Division February 6, 2009 i REPORT DOCUMENTATION PAGE Form...include area code) b. ABSTRACT c. THIS PAGE 18. NUMBER OF PAGES 17. LIMITATION OF ABSTRACT Description and Evaluation of GDEM -V 3.0 Michael R. Carnes...unlimited. Unclassified Unclassified Unclassified UL 24 Michael R. Carnes (228) 688-5648 The GDEM (Generalized Digital Environment Model) has served as

Novel Array-Based Target Identification for Synergistic Sensitization of Breast Cancer to Herceptin

DTIC Science & Technology

2010-05-01

Tatsuya Azum, Eileen Adamson, Ryan Alipio, Becky Pio, Frank Jones, Dan Mercola. Chip- on- chip analysis of mechanism of action of HER2 inhibition in...Munawar, Kutbuddin S. Doctor, Michael Birrer, Michael McClelland, Eileen Adamson, Dan Mercola. Egr1 regulates the coordinated expression of numerous...Kemal Korkmaz, Mashide Ohmichi, Eileen Adamson, Michael McClelland, Dan Mercola. Identification of genes bound and regulated by ATF2/c-Jun

Structuring Z Specifications with Views

DTIC Science & Technology

1994-03-01

Gregory Abowd, Michael Jackson , Jeannette Wing, Michal Young and Pamela Zave, who gave me helpful comments on drafts of this pa- per. I am also grateful to...1988. Uac94] Michael Jackson , "Software Development Method", in A Classical Mind: Essays in Honour of C.A.R Hoare, ed. A.W Roscoe, Prentice Hall...International, 1994. ,0 26 [Jon86] Cliff B. Jones, Systematic Software Development Using VDM, Prentice Hall International, 1986. [JZ93] Michael Jackson and

Test and Evaluation of the Navy Occupational Health Information Management System (NOHIMS).

DTIC Science & Technology

1986-07-01

Naval Shipyard for NOHIMS with the assistance of Todd Merrill from the University of Washington and Michael Jackson , another industrial hygienist...initialize NOHIMS and learn how to use the system. As the industrial component of NOHIMS became operational in Bremerton, Michael Jackson assumed the role...interacting with the system. Since NO|IIMS was introduced at Bremerton, Michael Jackson has been involved in all aspects of system start-up and maintenance

Vortex formation in magnetic narrow rings

NASA Astrophysics Data System (ADS)

Bland, J. A. C.

2002-03-01

Underlying the current interest in magnetic elements is the possibility such systems provide both for the study of fundamental phenomena in magnetism (such as domain wall trapping and spin switching) and for technological applications, such as high density magnetic storage or magnetic random access memories (MRAM). One key issue is to control the magnetic switching precisely. To achieve this one needs first to have a well defined and reproducible remanent state, and second the switching process itself must be simple and reproducible. Among the many studied geometries, rings are shown to exhibit several advantages over other geometries, in that they show relatively simple stable magnetic states at remanence, with fast and simple magnetisation switching mechanisms. This is borne out of our systematic investigation of the magnetic properties of epitaxial and polycrystalline Co rings, where both the static, dynamic and transport properties have been studied. Magnetic measurements and micromagnetic simulations show that for appropriate ring structures a two step switching process occurs at high fields, indicating the existence of two different stable states. In addition to the vortex state, which occurs at intermediate fields, we have identified a new bi-domain state, which we term the `onion state', corresponding to opposite circulation of the magnetisation in each half of the ring. The magnetic elements were fabricated using a new technique based on the pre-patterning of Si ring structures and subsequent epitaxial growth of Cu/Co/Cu sandwich films on top of the Si elements. This technique has allowed the growth of epitaxial fcc Co(001) structures and in contrast to conventional lithographic methods, no damage to the magnetic layer structure is introduced by the patterning process [1,2]. We have studied the magnetic switching properties of arrays of narrow Co(100) epitaxial ring magnets, with outer diameters between 1 μm and 2 μm, varying inner diameters and varying film thickness, using magneto-optic Kerr effect (MOKE) magnetometry. The data indicates that the outer diameter of the ring only plays a minor role in determining the value of the switching field. As a general trend, the switching field decreases with increasing ring width and with decreasing film thickness. In particular, the dependence of the switching field on ring width becomes more pronounced for smaller ring widths. This stems from the fact that the vortex state becomes more stable for the narrower rings due to the exchange energy contribution to the barrier for reversal to the onion state. Thicker films also favour the vortex state over the onion state, since the magnetostatic energy associated with the latter state increases with film thickness [3]. Using micromagnetic simulations we show also that the magnetisation reversal in narrow rings can take place via a nucleation-free domain wall motion process when a field pulse is applied in the plane of the film and perpendicular to the net magnetisation. Switching times of the order of 400 ps can be achieved with this approach. A lower bound for the depinning time of the domain walls and a weak dependence of the domain wall velocity with the applied field are described [4]. The magnetic nanostructure of epitaxial fcc Co/Cu(001) circular elements has been imaged with scanning electron microscopy with polarisation analysis (SEMPA) [5]. The elements vary from disks to rings according to the dimensions of the inner diameter of the ring structure and have a nominal composition 4 nm Au/2 nm Cu/34 nm Co/100 nm Cu. In this study the outer diameter was fixed at 1.7 μm while the smallest ring width varies in the range 0.3-0.5 μm. A closed flux quadrant configuration is observed for some of the disks, characteristic of systems with cubic anisotropy (i.e., near vortex structure), besides other more complex configurations at remanence. The width of the 90^o domain wall in the disks is around 0.20 ± 0.05 μm. This value is larger than what expected for continuous films and is a result of the constraints imposed by the geometry of the element. The value is in good agreement with micromagnetic calculations. For the rings we observe directly the `onion-state', the closest configuration to saturation that these structures allow [1]. The results prove that this state is stable in zero applied field. The internal structure of the two head-to-head domain walls in the onion state is analysed. Wider rings (ring width w=0.5 μm) present vortex walls, whereas thinner ones (ring width w=0.3 μm) exhibit transverse walls [6]. This is in good agreement with micromagnetic simulations. We have also investigated the magnetic states and the switching properties of magnetic rings using magneto-resistance (MR) measurements. We chose narrow rings, where particularly simple magnetic states are expected. Some of the rings have notches of different sizes that help to pin, and thereby define, the positions of domain walls. The rings were fabricated using a multi-stage lift-off process, where six non-magnetic contacts in different positions of the ring were made. The rings consist of polycrystalline Co or Ni_80Fe_20 3-30 nm thick capped with 6 nm Au, with outer ring diameter 1.4 μm, ring width 80 nm, and notches of different sizes. Conventional MR-H loop measurements with a fixed magnetic field direction, and measurements with rotating constant field magnitude were performed. In one example of the first type of MR measurements, the direction of the field and the contacts were chosen so that at saturation the magnetization is perpendicular to the current. As expected, at saturation the resistance is low whereas at remanence it is high. There is a clear two-step switching process between the `onion' state and the vortex state as expected from previous studies on rings [1]. During the first switching the resistance increases, corresponding to the transition into the vortex state. Since no domain wall is present between the contacts, the magnetization is everywhere parallel to the current, and the resistance is high. After the second switching into the reverse `onion' state a domain wall is now present between the contacts. This means some of the magnetization in the transverse domain wall is perpendicular to the current and hence the resistance decreases. This shows that one can clearly distinguish between the onion and vortex state using MR measurements. In addition, using the field dependent voltage drop between different contacts, the switching field at which each part of the ring reverses can be determined. >From the second type of measurements clear hysteretic behaviour is seen, indicating that there is some domain wall pinning. This demonstrates that the position of the domain walls can be identified by looking at the voltage drop between different contacts. By measuring at different magnitudes of the applied field the pinning strength of the domain walls is determined, and in particular the dependence of the domain wall pinning on the notch size. Furthermore the structure of the domain wall changes for different notch sizes, and hence the contribution of the wall to the resistance changes as well. Real-time measurements between different contacts might allow for domain wall speed measurements and other domain wall propagation studies. References: [1] J. Rothman, M. Kläui, L. Lopez-Diaz, C.A.F. Vaz, A. Bleloch, J.A.C. Bland, Z. Cui, R. Speaks, Phys. Rev. Lett. 86 (2001) 1098. [2] Z. Cui, J. Rothman, M. Kläui, L. Lopez-Diaz, C.A.F. Vaz, J.A.C. Bland, to be published. [3] M. Kläui, L. Lopez-Diaz, J. Rothman, C.A.F. Vaz, J.A.C. Bland, Z. Cui, J. Magn. Magn. Mat., to be published. [4] L. Lopez-Diaz, J. Rothman, M. Kläui, J.A.C. Bland, IEEE Trans. Mag. 36 (2000) 3155. [5] C.A.F. Vaz, L. Lopez-Diaz, M. Kläui, J.A.C. Bland, T.L. Monchesky, J. Unguris, Z. Cui, 46th MMM Conference, Seattle, 2001. [6] R. D. McMichael and M. J. Donahue, IEEE Trans. Mag. 33, 4167-4169 (1997).

Vortex rings in Bose gas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Belyaev, S. T., E-mail: bst@kiae.ru

2016-06-15

We consider excitations that exist, in addition to phonons, in the ideal Bose gas at zero temperature. These excitations are vortex rings whose energy spectrum is similar to the roton one in liquid helium.

Saturn's dynamic D ring

USGS Publications Warehouse

Hedman, M.M.; Burns, J.A.; Showalter, M.R.; Porco, C.C.; Nicholson, P.D.; Bosh, A.S.; Tiscareno, M.S.; Brown, R.H.; Buratti, B.J.; Baines, K.H.; Clark, R.

2007-01-01

The Cassini spacecraft has provided the first clear images of the D ring since the Voyager missions. These observations show that the structure of the D ring has undergone significant changes over the last 25 years. The brightest of the three ringlets seen in the Voyager images (named D72), has transformed from a narrow, <40-km wide ringlet to a much broader and more diffuse 250-km wide feature. In addition, its center of light has shifted inwards by over 200 km relative to other features in the D ring. Cassini also finds that the locations of other narrow features in the D ring and the structure of the diffuse material in the D ring differ from those measured by Voyager. Furthermore, Cassini has detected additional ringlets and structures in the D ring that were not observed by Voyager. These include a sheet of material just interior to the inner edge of the C ring that is only observable at phase angles below about 60??. New photometric and spectroscopic data from the ISS (Imaging Science Subsystem) and VIMS (Visual and Infrared Mapping Spectrometer) instruments onboard Cassini show the D ring contains a variety of different particle populations with typical particle sizes ranging from 1 to 100 microns. High-resolution images reveal fine-scale structures in the D ring that appear to be variable in time and/or longitude. Particularly interesting is a remarkably regular, periodic structure with a wavelength of ??? 30 ?? km extending between orbital radii of 73,200 and 74,000 km. A similar structure was previously observed in 1995 during the occultation of the star GSC5249-01240, at which time it had a wavelength of ??? 60 ?? km. We interpret this structure as a periodic vertical corrugation in the D ring produced by differential nodal regression of an initially inclined ring. We speculate that this structure may have formed in response to an impact with a comet or meteoroid in early 1984. ?? 2006 Elsevier Inc. All rights reserved.

Improved circumferential shaft seal

NASA Technical Reports Server (NTRS)

Ludwig, L. P.; Strom, T. N.

1974-01-01

Comparative tests of modified and unmodified carbon ring seals showed that addition of helical grooves to conventional segmented carbon ring seals reduced leakage significantly. Modified seal was insensitive to shaft runout and to flooding by lubricant.

Ethinyl Estradiol and Etonogestrel Vaginal Ring

MedlinePlus

... entering. The contraceptive ring is a very effective method of birth control but does not prevent the ... cases, you may need to use an additional method of birth control for the first seven days ...

Ring artifact reduction in synchrotron x-ray tomography through helical acquisition

NASA Astrophysics Data System (ADS)

Pelt, Daniël M.; Parkinson, Dilworth Y.

2018-03-01

In synchrotron x-ray tomography, systematic defects in certain detector elements can result in arc-shaped artifacts in the final reconstructed image of the scanned sample. These ring artifacts are commonly found in many applications of synchrotron tomography, and can make it difficult or impossible to use the reconstructed image in further analyses. The severity of ring artifacts is often reduced in practice by applying pre-processing on the acquired data, or post-processing on the reconstructed image. However, such additional processing steps can introduce additional artifacts as well, and rely on specific choices of hyperparameter values. In this paper, a different approach to reducing the severity of ring artifacts is introduced: a helical acquisition mode. By moving the sample parallel to the rotation axis during the experiment, the sample is detected at different detector positions in each projection, reducing the effect of systematic errors in detector elements. Alternatively, helical acquisition can be viewed as a way to transform ring artifacts to helix-like artifacts in the reconstructed volume, reducing their severity. We show that data acquired with the proposed mode can be transformed to data acquired with a virtual circular trajectory, enabling further processing of the data with existing software packages for circular data. Results for both simulated data and experimental data show that the proposed method is able to significantly reduce ring artifacts in practice, even compared with popular existing methods, without introducing additional artifacts.

3-(2-aminophenyl)-4-methyl-1,3-thiazole-2(3H)-thione as an ecofriendly sulphur transfer agent to prepare alkanethiols in high yield and high purity.

PubMed

Mehdid, Mohammed Amine; Djafri, Ayada; Roussel, Christian; Andreoli, Federico

2009-11-12

A new process is described for preparing very pure linear alkanethiols and linear alpha,omega-alkanedithiols using a sequential alkylation of the title compound, followed by a ring closure to quantitatively give the corresponding 3-methyl[1,3]thiazolo[3,2-a]-[3,1]benzimidazol-9-ium salt and the alkanethiol derivative under mild conditions. The alkanethiol and the heteroaromatic salt are easily separated by a simple extraction process. The intermediate thiazolium quaternary salts resulting from the first reaction step can be isolated in quantitative yields, affording an odourless protected form of the thiols.

α-Fluoro-α-nitro(phenylsulfonyl)methane as a fluoromethyl pronucleophile: Efficient stereoselective Michael addition to chalcones

PubMed Central

Prakash, G. K. Surya; Wang, Fang; Stewart, Timothy; Mathew, Thomas; Olah, George A.

2009-01-01

Highly efficient stereoselective 1,4-addition of racemic α-fluoro-α-nitro(phenylsulfonyl)methane (FNSM) as a fluoromethyl pronucleophile to α,β-unsaturated ketones using a wide range of chiral organobifunctional catalysts under moderate conditions in the absence of an additional base has been achieved. A series of catalysts was screened for the enantioselective addition of FNSM to chalcones and the catalysts CN I, CD I, QN I-IV, and QD I were found to enable this reaction, successfully providing exclusive 1,4-addition products stereoselectively in high yields (conversion, diastereomeric ratio, and enantiomeric excess). Studies involving a model reaction and systematic analysis of the absolute configuration support the suggested mechanism. PMID:19237559

Synthesis and biological evaluation of radio and dye labeled amino functionalized dendritic polyglycerol sulfates as multivalent anti-inflammatory compounds.

PubMed

Gröger, Dominic; Paulus, Florian; Licha, Kai; Welker, Pia; Weinhart, Marie; Holzhausen, Cornelia; Mundhenk, Lars; Gruber, Achim D; Abram, Ulrich; Haag, Rainer

2013-09-18

Herein we describe a platform technology for the synthesis and characterization of partially aminated, (35)S-labeled, dendritic polyglycerol sulfate (dPG(35)S amine) and fluorescent dPGS indocarbocyanine (ICC) dye conjugates. These polymer conjugates, based on a biocompatible dendritic polyglycerol scaffold, exhibit a high affinity to inflamed tissue in vivo and represent promising candidates for therapeutic and diagnostic applications. By utilizing a one-step sequential copolymerization approach, dendritic polyglycerol (Mn ≈ 4.5 kDa) containing 9.4% N-phthalimide protected amine functionalities was prepared on a large scale. Sulfation and simultaneous radio labeling with (35)SO3 pyridine complex, followed by cleavage of the N-phthalimide protecting groups, yielded dPG(35)S amine as a beta emitting, inflammation specific probe with free amino functionalities for conjugation. Furthermore, efficient labeling procedures with ICC via iminothiolane modification and subsequent "Michael" addition of the maleimide functionalized ICC dye, as well as by amide formation via NHS derivatized ICC on a dPGS amine scaffold, are described. The dPGS-ICC conjugates were investigated with respect to their photophysical properties, and both the radiolabeled and fluorescent compounds were comparatively visualized in histological tissue sections (radio detection and fluorescence microscopy) of animals treated with dPGS. Furthermore, cellular uptake of dPGS-ICC was found in endothelial cord blood (HUVEC) and the epithelial lung cells (A549). The presented synthetic routes allow a reproducible, controlled synthesis of dPGS amine on kilogram scale applying a one-pot batch reaction process. dPGS amine can be used for analysis via radioactivity or fluorescence, thereby creating a new platform for inflammation specific, multimodal imaging purposes using other attachable probes or contrast agents.

Unraveling the Molecular Complexity of O-Glycosylated Endogenous (N-Terminal) pro-B-Type Natriuretic Peptide Forms in Blood Plasma of Patients with Severe Heart Failure.

PubMed

Halfinger, Bernhard; Hammerer-Lercher, Angelika; Amplatz, Benno; Sarg, Bettina; Kremser, Leopold; Lindner, Herbert H

2017-01-01

Currently, N-terminal pro-B-type natriuretic peptide (NT-proBNP) and its physiologically active counterpart, BNP, are most frequently used as biomarkers for diagnosis, prognosis, and disease monitoring of heart failure (HF). Commercial NT-proBNP and BNP immunoassays cross-react to varying degrees with unprocessed proBNP, which is also found in the circulation. ProBNP processing and immunoassay response are related to O-linked glycosylation of NT-proBNP and proBNP. There is a clear and urgent need to identify the glycosylation sites in the endogenously circulating peptides requested by the community to gain further insights into the different naturally occurring forms. The glycosylation sites of (NT-) proBNP (NT-proBNP and/or proBNP) were characterized in leftovers of heparinized plasma samples of severe HF patients (NT-proBNP: >10000 ng/L) by using tandem immunoaffinity purification, sequential exoglycosidase treatment for glycan trimming, β-elimination and Michael addition chemistry, as well as high-resolution nano-flow liquid chromatography electrospray multistage mass spectrometry. We describe 9 distinct glycosylation sites on circulating (NT-) proBNP in HF patients. Differentially glycosylated variants were detected based on highly accurate mass determination and multistage mass spectrometry. Remarkably, for each of the identified proteolytic glycopeptides, a nonglycosylated form also was detectable. Our results directly demonstrate for the first time a rather complex distribution of the endogenously circulating glycoforms by mass spectrometric analysis in HF patients, and show 9 glycosites in human (NT-) proBNP. This information may also have an impact on commercial immunoassays applying antibodies specific for the central region of (NT-) proBNP, which detect mostly nonglycosylated forms. © 2016 American Association for Clinical Chemistry.

Hydrogels with Spatially and Temporally Controlled Properties to Control Cellular Interactions

NASA Astrophysics Data System (ADS)

Burdick, Jason

2011-03-01

Stem cells (e.g., mesenchymal stem cells, MSCs) respond to many cues from their microenvironment, which may include chemical signals, mechanics, and topography. Importantly, these cues may be incorporated into scaffolding to control stem cell differentiation and optimize their ability to produce tissues in regenerative medicine. Despite the significant amount of work in this area, the materials have been primarily static and uniform. To this end, we have developed a sequential crosslinking process that relies on our ability to crosslinked functional biopolymers (e.g., methacrylated hyaluronic acid, HA) in two steps, namely a Michael-type addition reaction to partially consume reactive groups and then a light-initiated free-radical polymerization to further crosslink the material. With light exposure during the second step comes control over the material in space (via masks and lasers) and time (via intermittent light exposure). We are applying this technique for numerous applications. For example, when the HA hydrogels are crosslinked with MMP degradable peptides with thiol termini during the first step, a material that can be degraded by cells is obtained. However, cell-mediated degradation is obstructed with the introduction of kinetic chains during the second step, leading to spatially controlled cell degradability. Due to the influence of cellular spreading on MSC differentiation, we have controlled cell fates by controlling their spread ability, for instance towards osteoblasts in spread areas and adipocytes when cell remained rounded. We are also using the process of stiffening with time to investigate mechanically induced differentiation, particularly in materials with evolving mechanics. Overall, these advanced HA hydrogels provide us the opportunity to investigate diverse and controlled material properties on MSC interactions.

Nitrile O-ring Cracking: A Case of Vacuum Flange O-ring Failures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dees, Craig

2016-07-01

A review of recent nitrile O-ring failures in ISO-KF vacuum flange connections in glovebox applications is presented. An investigation of a single “isolated” o-ring failure leads to the discovery of cracked nitrile o-rings in a glovebox atmospheric control unit. The initial cause of the o-ring failure is attributed to ozone degradation. However, additional investigation reveals nitrile o-ring cracking on multiple gloveboxes and general purpose piping, roughly 85% of the nitrile o-rings removed for inspection show evidence of visible cracking after being in service for 18 months or less. The results of material testing and ambient air testing is presented, elevatedmore » ozone levels are not found. The contributing factors of o-ring failure, including nitrile air sensitivity, inadequate storage practices, and poor installation techniques, are discussed. A discussion of nitrile o-ring material properties, the benefits and limitations, and alternate materials are discussed. Considerations for o-ring material selection, purchasing, storage, and installation are presented in the context of lessons learned from the nitrile o-ring cracking investigation. This paper can be presented in 20 minutes and does not require special accommodations or special audio visual devices.« less

Arcs and Clumps in the Uranian Lambda Ring

NASA Technical Reports Server (NTRS)

Showalter, Mark R.

1995-01-01

Careful reprocessing of the Voyager images reveals that the Uranian lambda ring has marked longitudinal variations in brightness comparable in magnitude to those in Saturn's F ring and Neptune's Adams ring. The ring's variations show a dominant five-cycle (72-degree) periodicity, although additional structure down to scales of about 0.5 degree is also present. The ring's shape is defined by a small overall eccentricity plus a six-cycle (60-degree) sinusoidal variation of radial amplitude around 4 kilometers. Both of these properties can be explained by the resonant perturbations of a moon at a semimajor axis of 56,479 kilometers, but no known moon orbits at this location. Unfortunately, the mass required suggests that such a body should have been imaged by Voyager.

Searching for a Different Understanding of Operational Art

DTIC Science & Technology

2016-05-26

that “hampered by 35 Bruce Menning, “Operational Art’s Origins,” in Historical Perspectives of the Operational Art, ed. Michael D. Krause and R. Cody...war or theater of 43 Clayton Newell, “Introduction,” in On Operational Art, ed. Clayton Newell and Michael Krause (Washington, DC: US Army Center of...Menning, Bruce. “Operational Art’s Origins.” In Historical Perspectives of the Operational Art, edited by Michael D. Krause and R. Cody Phillips, 3

Preparing Brigade Combat Team Soldiers for Mission Readiness Through Research on Intangible Psychological Constructs and their Applications: Validation and Pilot

DTIC Science & Technology

2015-01-01

and their Applications: Validation and Pilot Steven N. Aude Kenneth Nicely Michael A. Lodato ICF International Christopher L. Vowels...CONTRACT OR GRANT NUMBER W5J9CQ-11-0009 5b. PROGRAM ELEMENT NUMBER 622785 6. AUTHOR(S) Steven N. Aude, Kenneth Nicely, Michael A... Michael A. Lodato ICF International Christopher L. Vowels U.S. Army Research Institute Fort Hood Research Unit Brian T. Crabb

Gas Control and Thermal Modeling Methods for Pressed Pellet and Fast Rise Thin-Film Thermal Batteries

DTIC Science & Technology

2015-09-01

Thin-Film Thermal Batteries by Frank C Krieger and Michael S Ding Approved for public release; distribution unlimited...Laboratory Gas Control and Thermal Modeling Methods for Pressed Pellet and Fast Rise Thin-Film Thermal Batteries by Frank C Krieger and Michael S...Batteries 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Frank C Krieger and Michael S Ding 5d. PROJECT NUMBER

Production of a Novel OX40 Ligand for Clinical Use

DTIC Science & Technology

2012-10-01

inhibitory to the detection of mycoplasma. 19.0 TECHNICAL REFERENCES 19.1 Barile , Michael F. and McGarrity, Gerard J. (1983). "Isolation of Mycoplasmas from...Edition, Section 2.6.7, Mycoplasmas. 19.4 McGarrity, Gerard J. and Barile , Michael F. (1983). "Use of Indicator Cell Lines for Recovery and...test material will be discarded following study completion unless otherwise requested by Sponsor. 20.0 REFERENCES 20.1 Barile , Michael F. and

Magnetic Insulation in Coaxial Transmission Lines with an External Magnetic Field

DTIC Science & Technology

1980-03-13

A. Mostrom, Michael E. Jones, and Lester E. Thode SUBMITTED TO: Physical Review Letters March 13, 1980 SöKOK_Kä^MJ!L;; ÄgEie?©d tea gas &c...Number Assigned by Contract Monitor: SLL 81- 262 Comments on Document: Archive, RRI, DEW . From Physical Review Letters Descriptors, Keywords: Magnetic...Source of Document: DEW MAGNETIC INSULATION IN COAXIAL TRANSMISSION LINES WITH AN EXTERNAL MAGNETIC FIELD Michael A. Mostrom, Michael E. Jones, and

The Russo-Japanese War, Lessons Not Learned

DTIC Science & Technology

2003-05-06

USACGSC, August, 2002), CR3.7-1--CR3.7-14; Michael Howard , “Men Against Fire, Expectations of War in 1914,” International Security (Summer 1984): 41-57...169; Carl von Clausewitz, On War, trans. and ed. Michael Howard and Peter Paret (Princeton: Princeton University Press, 1984), 37-38. 8Service in...Cleator, P. Weapons of War. New York: Thomas Y. Crowell Company, 1967. Clausewitz, Carl von. On War. Edited and translated by Michael Howard and

Evaluating perceptions of the effectiveness of the community advisory panel model for enhancing service delivery to marginalized populations.

PubMed

Ramsay, Jason T; Smith, Peter; Thompson, Alison; O'Campo, Patricia; Nisenbaum, Rosane; Watson, Priya; Park-Wylie, Laura; Bryant, Toba; Tandon, Reena; Farah, Mohammed

2012-01-01

The objective of this study was to evaluate perceptions of the effectiveness of the community advisory panels (CAPs) at St. Michael's Hospital, in Toronto, Canada. A qualitative design was employed. Participants included hospital staff, patients, Community Advisory Panel chairs, and key informants from community services in the St. Michael's Hospital catchment area. An online survey about awareness of the CAPs and CAP accomplishments; (2) Key informants interviews; and (3) Review of memos and meeting minutes of the CAPs to assess their impact in the hospital and the community. St. Michael's Hospital was the setting of the study. Descriptive statistics were generated for the survey data. Qualitative interview data were coded for major themes. Participants included hospital staff, patients, CAP chairs, and key informants from community services in the St. Michael's Hospital catchment area. Although the CAPs initiated and implemented an array of programs and services at St. Michael's Hospital, the visibility of the CAPs and their service to the hospital and community were very low. Themes that emerged from the semistructured interviews involved the visibility, effectiveness, and role of the CAPs in the hospital. Although the CAPs at St. Michael's Hospital appear to be an effective model for community responsiveness, the visibility of their work in the hospital and community was very low. © 2012 Wiley Periodicals, Inc.

A C2HC zinc finger is essential for the RING-E2 interaction of the ubiquitin ligase RNF125

PubMed Central

Bijlmakers, Marie-José; Teixeira, João M. C.; Boer, Roeland; Mayzel, Maxim; Puig-Sàrries, Pilar; Karlsson, Göran; Coll, Miquel; Pons, Miquel; Crosas, Bernat

2016-01-01

The activity of RING ubiquitin ligases (E3s) depends on an interaction between the RING domain and ubiquitin conjugating enzymes (E2), but posttranslational events or additional structural elements, yet largely undefined, are frequently required to enhance or regulate activity. Here, we show for the ubiquitin ligase RNF125 that, in addition to the RING domain, a C2HC Zn finger (ZnF) is crucial for activity, and a short linker sequence (Li2120-128) enhances activity. The contribution of these regions was first shown with truncated proteins, and the essential role of the ZnF was confirmed with mutations at the Zn chelating Cys residues. Using NMR, we established that the C2HC ZnF/Li2120-128 region is crucial for binding of the RING domain to the E2 UbcH5a. The partial X-ray structure of RNF125 revealed the presence of extensive intramolecular interactions between the RING and C2HC ZnF. A mutation at one of the contact residues in the C2HC ZnF, a highly conserved M112, resulted in the loss of ubiquitin ligase activity. Thus, we identified the structural basis for an essential role of the C2HC ZnF and conclude that this domain stabilizes the RING domain, and is therefore required for binding of RNF125 to an E2. PMID:27411375

Michael Griffin House Science Committee Hearing

NASA Image and Video Library

2005-06-27

NASA Administrator Michael Griffin prepares to testify at a hearing before the House Science Committee, Tuesday, June 28, 2005, Rayburn House Office building, Washington. Photo Credit: (NASA/Bill Ingalls)

Geophysicists

NASA Astrophysics Data System (ADS)

2004-06-01

In Memoriam: James R. Holton, Buford K. Meade, Mikhail I. Pudovkin; Honors: Michel Blanc, Alberto Borges, Paola Vannucchi, Michael A. Hapgood, Subir Banerjee, Lev Vinnik, John Wahr, Forrest Mozer, Vladimir N. Zharkov, Michael Ghil

Development of an Acoustic Levitation Linear Transportation System Based on a Ring-Type Structure.

PubMed

Thomas, Gilles P L; Andrade, Marco A B; Adamowski, Julio Cezar; Silva, Emilio Carlos Nelli

2017-05-01

A linear acoustic levitation transportation system based on a ring-type vibrator is presented. The system is composed by two 21-kHz Langevin transducers connected to a ring-shaped structure formed by two semicircular sections and two flat plates. In this system, a flexural standing wave is generated along the ring structure, producing an acoustic standing wave between the vibrating ring and a plane reflector located at a distance of approximately a half wavelength from the ring. The acoustic standing wave in air has a series of pressure nodes, where small particles can be levitated and transported. The ring-type transportation system was designed and analyzed by using the finite element method. Additionally, a prototype was built and the acoustic levitation and transport of a small polystyrene particle was demonstrated.

Michael Griffin House Science Committee Hearing

NASA Image and Video Library

2005-06-27

Rep. Bart Gordon, D-TN., questions NASA Administrator Michael Griffin during a House Science Committee hearing, Tuesday, June 28, 2005, Rayburn House Office building, Washington. Photo Credit: (NASA/Bill Ingalls)

ASK Talks with Dr. Michael Hecht

NASA Technical Reports Server (NTRS)

Hecht, Michael

2003-01-01

Michael Hecht has been a member of NASA's Jet Propulsion Laboratory (JPL) staff since 1982. He is currently Project Manager and co-investigator for the Mars Environmental Compatibility Assessment (MECA)

Michael Thackeray on Lithium-air Batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thackeray, Michael

2009-01-01

Michael Thackeray, Distinguished Fellow at Argonne National Laboratory, speaks on the new technology Lithium-air batteries, which could potentially increase energy density by 5-10 times over lithium-ion batteries.

Michael Thackeray on Lithium-air Batteries

ScienceCinema

Thackeray, Michael

2018-02-06

Michael Thackeray, Distinguished Fellow at Argonne National Laboratory, speaks on the new technology Lithium-air batteries, which could potentially increase energy density by 5-10 times over lithium-ion batteries.

Diastereoselective Synthesis of Seven-Membered Ring trans-Alkenes from Dienes and Aldehydes by Silylene Transfer

PubMed Central

Greene, Margaret A.; Prévost, Michel; Tolopilo, Joshua; Woerpel, K. A.

2012-01-01

Silver-catalyzed silylene transfer to alkenes formed vinylsilacyclopropanes regioselectively. These allylic silanes underwent additions to aldehydes to form seven-membered ring trans-alkenes with high diastereoselectivity. The high reactivity of the trans alkenes is evidenced by their formal [1,3]-sigmatropic rearrangement reactions and their rapid additions of oxygen–hydrogen bonds across the carbon–carbon double bonds. PMID:22780578

Sequential EMT-MET induces neuronal conversion through Sox2

PubMed Central

He, Songwei; Chen, Jinlong; Zhang, Yixin; Zhang, Mengdan; Yang, Xiao; Li, Yuan; Sun, Hao; Lin, Lilong; Fan, Ke; Liang, Lining; Feng, Chengqian; Wang, Fuhui; Zhang, Xiao; Guo, Yiping; Pei, Duanqing; Zheng, Hui

2017-01-01

Direct neuronal conversion can be achieved with combinations of small-molecule compounds and growth factors. Here, by studying the first or induction phase of the neuronal conversion induced by defined 5C medium, we show that the Sox2-mediated switch from early epithelial–mesenchymal transition (EMT) to late mesenchymal–epithelial transition (MET) within a high proliferation context is essential and sufficient for the conversion from mouse embryonic fibroblasts (MEFs) to TuJ+ cells. At the early stage, insulin and basic fibroblast growth factor (bFGF)-induced cell proliferation, early EMT, the up-regulation of Stat3 and Sox2, and the subsequent activation of neuron projection. Up-regulated Sox2 then induced MET and directed cells towards a neuronal fate at the late stage. Inhibiting either stage of this sequential EMT-MET impaired the conversion. In addition, Sox2 could replace sequential EMT-MET to induce a similar conversion within a high proliferation context, and its functions were confirmed with other neuronal conversion protocols and MEFs reprogramming. Therefore, the critical roles of the sequential EMT-MET were implicated in direct cell fate conversion in addition to reprogramming, embryonic development and cancer progression. PMID:28580167

Atomic model for the membrane-embedded VO motor of a eukaryotic V-ATPase.

PubMed

Mazhab-Jafari, Mohammad T; Rohou, Alexis; Schmidt, Carla; Bueler, Stephanie A; Benlekbir, Samir; Robinson, Carol V; Rubinstein, John L

2016-11-03

Vacuolar-type ATPases (V-ATPases) are ATP-powered proton pumps involved in processes such as endocytosis, lysosomal degradation, secondary transport, TOR signalling, and osteoclast and kidney function. ATP hydrolysis in the soluble catalytic V 1 region drives proton translocation through the membrane-embedded V O region via rotation of a rotor subcomplex. Variability in the structure of the intact enzyme has prevented construction of an atomic model for the membrane-embedded motor of any rotary ATPase. We induced dissociation and auto-inhibition of the V 1 and V O regions of the V-ATPase by starving the yeast Saccharomyces cerevisiae, allowing us to obtain a ~3.9-Å resolution electron cryomicroscopy map of the V O complex and build atomic models for the majority of its subunits. The analysis reveals the structures of subunits ac 8 c'c″de and a protein that we identify and propose to be a new subunit (subunit f). A large cavity between subunit a and the c-ring creates a cytoplasmic half-channel for protons. The c-ring has an asymmetric distribution of proton-carrying Glu residues, with the Glu residue of subunit c″ interacting with Arg735 of subunit a. The structure suggests sequential protonation and deprotonation of the c-ring, with ATP-hydrolysis-driven rotation causing protonation of a Glu residue at the cytoplasmic half-channel and subsequent deprotonation of a Glu residue at a luminal half-channel.

Dr Michaels® product family (also branded as Soratinex®) versus Methylprednisolone aceponate - a comparative study of the effectiveness for the treatment of plaque psoriasis.

PubMed

Hercogovấ, J; Fioranelli, M; Gianfaldoni, S; Chokoeva, A A; Tchernev, G; Wollina, U; Tirant, M; Novotny, F; Roccia, M G; Maximov, G K; França, K; Lotti, T

2016-01-01

As one of the most common dermatologic chronic-recurrent disease, variable therapeutic options are available today for management of psoriasis. Although topical high potency corticosteroids, alone or in association with salicylic acid or vitamin D analogues, are still considered the best treatment, they do not seem to possess the capability for a long-term control of the disease or prevent recurrences, as their side effects are major contraindications for continuative use. The aim of this study was to investigate whether Dr. Michaels® product family is comparable to methylprednisolone aceponate (MPA) as a viable alternative treatment option for the treatment and management of stable chronic plaque psoriasis. Thirty adults (13 male, 17 female, mean age 40 years) with mild to severe stable chronic plaque psoriasis, were included in the study. Patients were advised to treat the lesions of the two sides of their body (left and right) with two different unknown modalities for 8 weeks; the pack of Dr. Michaels® products on the left side (consisting of a cleansing gel, an ointment and a skin conditioner) and a placebo pack on the right side, consisting of a cleansing gel, methylprednisolone ointment and a placebo conditioner. Assessment was done using the Psoriasis Activity Severity Index (PASI) scores before treatment and after 2, 4, 6 and 8 weeks. The results achieved with the Dr. Michaels® (Soratinex®) product family for the treatment of chronic plaque psoriasis were better than the results achieved with methylprednisolone aceponate (MPA), even though quicker resolution was achieved with the steroid with 45% of patients achieving resolution within 8-10 days in comparison to 5-6 weeks in the Dr. Michaels® (Soratinex®) group. Before therapy, the mean PASI score of the LHS in Dr. Michaels® (Soratinex®) group was 13.8±4.1 SD and 14.2±4.2 SD in the RHS methylprednisolone aceponate (MPA) group. After 8 weeks of treatment 62% of the Dr. Michaels® (Soratinex®) group had achieved resolution whilst in the methylprednisolone aceponate (MPA) group, the figure remained at 45%. The mean PASI score after 8 weeks of treatment was calculated and in the LHS Dr. Michaels® (Soratinex®) group it was 2.8±1.6 SD and 6.8±2.4 SD in the RHS methylprednisolone aceponate group. In the RHS -methylprednisolone aceponate (MPA) group, 22% of patients failed to respond to the treatment in comparison to 6% in the LHS Dr. Michaels® (Soratinex®) group. Based on the results of this study, Dr. Michaels® products are a more effective treatment option, with insignificant side effects, compared to local treatment with methylprednisolone aceponate (MPA).

Grafting-Density Effects, Optoelectrical Properties and Nano-Patterning of Poly(para-Phenylene) Brushes

DTIC Science & Technology

2013-01-01

NAME OF RESPONSIBLE PERSON 19b. TELEPHONE NUMBER S. Michael Kilbey Dawen Li, Jimmy W. Mays , S. Michael Kilbey II, Jihua Chen, Jose Alonzo, Xiang Yu...Dawen Li,d Jimmy W. Mays ,be Bobby G. Sumpteraf and S. Michael Kilbey II*eg Well-defined conjugated polymers in confined geometries are chal- lenging to...relationships of conned thin lms and may serve as a basis to understand polymer micelles, polymer-stabilized colloid particles, or interfaces compatibi

A Parametric Regression of the Cost of Base Realignment Action (COBRA) Model

DTIC Science & Technology

1993-09-20

Douglas D. Hardman , Captain, USAF Michael S. Nelson, Captain, USAF AFIT/GEE/ENS/93S-03 93 P’ 8 143 Approved for public release, distribution unlimited 93... Hardman CLASS: GEE 93S Captain Michael Nelson TITLE: A Parametric Regression of the Cost of Base Realignment Action (COBRA) Model DEFENSE DATE: 20...Science in Engineering and Environmental Management Douglas D. Hardman , B.S.E.E. Michael S. Nelson, B.S.C.E Captain, USAF Captain, USAF September 1993

Deception in Covert Nuclear Weapons Development: A Framework to Identify, Analyze, and Mitigate Future Long-Term Deception Efforts

DTIC Science & Technology

2016-03-01

In March, shortly after the BJP’s electoral victory, senior foreign policy advisor N . N . Jha informed U.S. embassy officials in New Delhi that the...College, 1998. Barker, Brian, Michael Clark, Peter Davis, Mark Fisk, Michael Hedlin, Hans Israelsson, Vitaly Khalturin, et al. "Monitoring Nuclear...Pretoria, South Africa, 1981. Mihalka, Michael, German Strategic Deception in the 1930’s, Santa Monica, Calif.: RAND Corporation, N -1557-NA, 1980

Michael Polanyi: Science as Personal Knowledge and Social Practice.

PubMed

Nye, Mary Jo

2017-03-20

Tacit knowing: 2016 marked the 125th anniversary of the birth of the physical chemist Michael Polanyi, as well as the 40th of his death. This essay discusses his philosophy of science-in particular, his most significant work in this area, Personal Knowledge-from the perspective of his personal biography, as well as its lasting influence on the social sciences. In the photograph: Michael Polanyi at the Fritz Haber Institute in 1968. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Proceedings, Conference and Training Workshop on Wildlife Hazards to Aircraft Held at Charleston, South Carolina on 22-25 May 1984

DTIC Science & Technology

1984-05-25

Aircraft ~.Aut@i~Michael J . Harrison/Sidney A. Gauthreaux, Jr., -Lilia A. Abron-Robinson .WeUi’N.(TiS 9. Pordoni,mg Ogon.m,t,. Nome and AdOda.0...Michael J . Harrison (AAS-330) 16. A4049ract , /-7hese proceedings were developed to enhance information exchange and improve understanding and control of...Wildlife Hazards to Aircraft S Conference and Training Workshop Edited by: Michael J . Harrison Federal Aviation Administration . Dr. Sidney A

Maniac Talk - Michael Kurylo

NASA Image and Video Library

2016-11-16

Michael Kurylo Maniac Lecture, November 16, 2016 NASA climate scientist Michael Kurylo presented a Maniac lecture entitled, "An Uncharted Journey: How I Became an Atmospheric Scientist Rather than a Cowboy or a Farmer." Mike described the path that took him from post-WW II housing projects to and through a rural Connecticut neighborhood, how he became convinced about the unrealistic nature of some early naive career dreams, and how he eventually arrived at a career in atmospheric science (research and program management, and their interface with international environmental policy).

Early Prediction of Lupus Nephritis Using Advanced Proteomics

DTIC Science & Technology

2010-06-01

SELDI-TOF-MS. Additional proteomic profiling studies using NMR- and MS-based metabonomics have been completed, and LC/MS based protein profiling using...Flight mass spectrometry (SELDI-TOF-MS). Changes in proteomic profiles will be confirmed and enhanced using NMR- and MS-based metabonomics , by Dr...performed using NMR- and MS-based metabonomics at Miami University, in the laboratory of Dr. Michael Kennedy. Initial spectra and profiles obtained show

COMPETING IN THE SOCIAL BATTLESPACE: INFLUENCING THE THREE DOMAINS

DTIC Science & Technology

2017-06-01

Legacy (Knopf Doubleday Publishing Group, 2009), 33. 39 Norman Polmar and Kenneth J. Moore, Cold War Submarines: The Design and Construction of U.S...and shot Brown six times in the back, killing him. Michael Brown would lay four hours on the pavement as additional police officers and...Cornell University Press. Polmar, Norman, and Kenneth J. Moore. Cold War Submarines: The Design and Construction of U.S. and Soviet Submarines

Equipping Network Warfare: Industrial-Era Bureaucracies for Information-Era Weapons

DTIC Science & Technology

2009-04-01

Scientist , Air Force Research Lab Information Directorate; Dr. John Parker, Chief Technical Officer, GlimmerGlass Corportation; Mr. J. Michael Kretzer...operations.2 Additionally, the Air Force has established a functional management office within the Air Staff, has created a formal schoolhouse and...found that overall research and development costs exceeded their budget by 40% in Fiscal Year 2005 (up from 27% in 2000), while total acquisition costs

Fluoride-Mediated Dephosphonylation of α-Diazo-β-carbonyl Phosphonates.

PubMed

Phatake, Ravindra S; Mullapudi, Venkannababu; Wakchaure, Vivek C; Ramana, Chepuri V

2017-01-20

The possibility of fluoride-mediated selective dephosphonylation of α-diazo-β-carbonyl phosphonates such as the Ohira-Bestmann reagent has been proposed and executed. The resulting α-diazocarbonyl intermediates undergo a (3 + 2)-cycloaddition at room temperature with conjugated olefins and benzynes. Interestingly, under the current conditions, the resulting cycloaddition products underwent either N-acylation (with excess α-diazo-β-carbonyl phosphonates) or Michael addition (with conjugated olefins).

Conformational Studies of 1-OCTYNE from Rotational Spectroscopy

NASA Astrophysics Data System (ADS)

Maturo, Mark P.; Obenchain, Daniel A.; Melchreit, Robert; Cooke, S. A.; Novick, Stewart E.

2017-06-01

Alkanes of the form CH_3(CH_2)_nCH_3 generally favor ground state geometries that have co-planar carbon atoms. In this study, we have looked at a long chain hydrocarbon with a terminal carbon-carbon triple bond, viz., 1-octyne. Guided by the results of the 1-hexyne studies, three possible low energy conformers were studied which we reference as anti-anti (AA, straight chain), anti-gauche (AG, terminal methyl group is gauche), and gauche-anti (GA, ethyl group is gauche). An initial broadband chirp-pulse was performed between 7-13 GHz and a total of sixty-eight transitions were fit. Additional measurements on a Balle Flygare cavity instrument yielded an additional seventy-three lines belonging to three of the conformers. Transitions for all 8 of the singly substituted ^{13}C isotopologues, in natural abundance, have also been observed for the AA conformer. Ab-initio optimizations at the MP2/6-311++g(2d,2p) level of theory and basis set for these three conformers will be compared to experimental rotational constants. Structure determinations of the AA conformer will also be discussed. Atticks, K.; Bohn, R. K.; Michaels H. H. Int'l J. of Quantum Chem. 2001, 85, 514-519; Utzat, K.; Bohn, R. K.; Michaels H. H. J. Mol. Struct. 2007, 841, 22-27

Effects of simultaneous and optimized sequential cardiac resynchronization therapy on myocardial oxidative metabolism and efficiency.

PubMed

Christenson, Stuart D; Chareonthaitawee, Panithaya; Burnes, John E; Hill, Michael R S; Kemp, Brad J; Khandheria, Bijoy K; Hayes, David L; Gibbons, Raymond J

2008-02-01

Cardiac resynchronization therapy (CRT) can improve left ventricular (LV) hemodynamics and function. Recent data suggest the energy cost of such improvement is favorable. The effects of sequential CRT on myocardial oxidative metabolism (MVO(2)) and efficiency have not been previously assessed. Eight patients with NYHA class III heart failure were studied 196 +/- 180 days after CRT implant. Dynamic [(11)C]acetate positron emission tomography (PET) and echocardiography were performed after 1 hour of: 1) AAI pacing, 2) simultaneous CRT, and 3) sequential CRT. MVO(2) was calculated using the monoexponential clearance rate of [(11)C]acetate (k(mono)). Myocardial efficiency was expressed in terms of the work metabolic index (WMI). P values represent overall significance from repeated measures analysis. Global LV and right ventricular (RV) MVO(2) were not significantly different between pacing modes, but the septal/lateral MVO(2) ratio differed significantly with the change in pacing mode (AAI pacing = 0.696 +/- 0.094 min(-1), simultaneous CRT = 0.975 +/- 0.143 min(-1), and sequential CRT = 0.938 +/- 0.189 min(-1); overall P = 0.001). Stroke volume index (SVI) (AAI pacing = 26.7 +/- 10.4 mL/m(2), simultaneous CRT = 30.6 +/- 11.2 mL/m(2), sequential CRT = 33.5 +/- 12.2 mL/m(2); overall P < 0.001) and WMI (AAI pacing = 3.29 +/- 1.34 mmHg*mL/m(2)*10(6), simultaneous CRT = 4.29 +/- 1.72 mmHg*mL/m(2)*10(6), sequential CRT = 4.79 +/- 1.92 mmHg*mL/m(2)*10(6); overall P = 0.002) also differed between pacing modes. Compared with simultaneous CRT, additional changes in septal/lateral MVO(2), SVI, and WMI with sequential CRT were not statistically significant on post hoc analysis. In this small selected population, CRT increases LV SVI without increasing MVO(2), resulting in improved myocardial efficiency. Additional improvements in LV work, oxidative metabolism, and efficiency from simultaneous to sequential CRT were not significant.

Stabilized single-longitudinal-mode erbium fibre laser employing silicon-micro-ring resonator and saturable absorber

NASA Astrophysics Data System (ADS)

Hsu, Yung; Yeh, Chien-Hung; Chow, Chi-Wai; Chang, Yuan-Chia; Cheng, Hao-Yun

2018-07-01

In the paper, a wavelength-tunable erbium-doped fiber (EDF) ring laser with stable single-longitudinal-mode (SLM) oscillation is proposed and investigated. Here, a silicon-micro-ring-resonator can be applied in a laser cavity for tuning wavelength in the C-band range. To complete the SLM oscillation, an unpumped EDF-based saturable absorber is used to act as ultra-narrowband filter for suppressing other oscillation modes. Additionally, the output stabilities of power and wavelength in the proposed EDF ring laser are also executed and discussed.

78 FR 4406 - Notice of Commission Staff Attendance

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-22

... Carolina Electric & Gas Company For more information, contact Michael Lee, Office of Energy Market Regulation, Federal Energy Regulatory Commission at (202) 502-8658 or Michael.Lee@ferc.gov . Dated: January...

Goddard Queen Visit

NASA Image and Video Library

2007-05-07

Prince Philip greets astronauts from STS-125 L to R Andrew J Feustel, Michael T Goode, K. Megan McArthur, Michael J. Massimino, Gregory C. Johnson, and Commander Scott D. Altman. Photo Credit: (NASA/Chris Gunn)

78 FR 36183 - Notice of Commission Staff Attendance

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-17

... Electric & Gas Company For More Information Contact: Michael Lee, Office of Energy Market Regulation, Federal Energy Regulatory Commission at (202) 502-8658 or Michael.Lee@ferc.gov . Dated: June 11, 2013...

The reliability of using the single-biopsy approach to assess basal muscle protein synthesis rates in vivo in humans.

PubMed

Burd, Nicholas A; Groen, Bart B L; Beelen, Milou; Senden, Joan M G; Gijsen, Annemie P; van Loon, Luc J C

2012-07-01

It has recently been proposed that basal muscle protein synthesis can be effectively assessed by measuring the background enrichment in total plasma protein, thereby omitting the initial biopsy, and determining the difference in enrichment from a single muscle biopsy obtained during a primed continuous infusion of isotope-labeled amino acids. We determined the reliability of calculating basal mixed muscle protein fractional synthetic rates (FSRs) from mixed plasma proteins and a single muscle biopsy compared against the sequential muscle biopsy approach. Ten men (age, 23 ± 1 years; body mass index, 22 ± 1 kg∙m(-2)) received muscle biopsies of the vastus lateralis after 2 and 4 hours of a primed continuous infusion of l-[ring-(13)C(6)]phenylalanine. Mixed muscle protein FSR was calculated from baseline plasma enrichments and muscle protein enrichments determined from the biopsy at 2 hours (1BX SHORT) or 4 hours (1BX LONG), or between muscle protein enrichments at 2 and 4 hours (2BX) of the infusion. No differences (P = .50) were observed in mixed muscle protein FSR, using plasma [ring-(13)C(6)]phenylalanine enrichments as the precursor, between the 1BX SHORT (0.031% ± 0.010%∙h(-1)), 1BX LONG (0.032% ± 0.007%∙h(-1)), or 2BX (0.035% ± 0.011%∙h(-1)) approach. A significant correlation was observed between the calculated muscle protein FSR assessed using the 1BX LONG and 2BX approach (r = 0.7, P = .02). Our data demonstrate that the single-biopsy approach, irrespective of whether the biopsy is obtained at 2 or 4 hours, can be used as a surrogate for the sequential-biopsy approach to determine basal muscle protein synthesis in a group. Copyright © 2012 Elsevier Inc. All rights reserved.

The Application of a Cylindrical-spherical Floating Ring Bearing as a Device to Control Stability of Turbogenerators

NASA Technical Reports Server (NTRS)

Leung, P. S.; Craighead, I. A.; Wilkinson, T. S.

1991-01-01

The development of a new device to control stability of turbogenerators is described. The device comprises a floating ring installed between the journal and bearing housing of a fluid film bearing. The journal and the inner surface of the ring are cylindrical while the outer surface of the ring and bearing surface are spherical providing axial location of the ring and self-alignment of the bearing. The employment of this device would lead to a consistent machine performance. System stability may be controlled by changing a number of bearing and floating ring parameters. This device also offers an additional advantage of having a very low frictional characteristic. A feasibility study was carried out to investigate the suitability of the new device to turbogenerator applications. Both theoretical analysis and experimental observations were carried out. Initial results suggest that the new floating ring device is a competitive alternative to other conventional arrangements.

Radiation synthesis of a new amidoximated UHMWPE fibrous adsorbent with high adsorption selectivity for uranium over vanadium in simulated seawater

NASA Astrophysics Data System (ADS)

Gao, Qianhong; Hu, Jiangtao; Li, Rong; Xing, Zhe; Xu, Lu; Wang, Mouhua; Guo, Xiaojing; Wu, Guozhong

2016-05-01

A new kind of highly efficient adsorbent material has been fabricated in this study for the purpose of extracting uranium from seawater. Ultra-high molecular weight polyethylene (UHMWPE) fiber was used as a trunk material for the adsorbent, which was prepared by a series of modification reactions, as follows: (1) grafting of glycidyl methacrylate (GMA) and methyl acrylate (MA) onto UHMWPE fibers via 60Co γ-ray pre-irradiation; (2) aminolyzation of UHMWPE fiber by the ring-opening reaction between of epoxy groups PGMA and ethylene diamine (EDA); (3) Michael addition of amino groups with acrylonitrile (AN) to yield nitrile groups; (4) amidoximation of the attached nitrile moieties by hydroxylamine in dimethyl sulfoxide-water mixture. Modified UHMWPE fibers were characterized by means of attenuated total reflectance-Fourier transformed infrared spectroscopy (ATR-FTIR), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) to confirm the attachment of amidoxime (AO) groups onto the UHMWPE fibers. The results of X-ray diffraction (XRD) and single fiber tensile strength verified that the modified UHMWPE fiber retained excellent mechanical properties at a low absorbed radiation dose. The adsorption performance of the UHMWPE fibrous adsorbent was evaluated by subjecting it to an adsorption test in simulated seawater using a continuous-flow mode. The amount of uranium adsorbed by this AO-based UHMWPE fibrous adsorbent was 1.97 mg-U/g after 42 days. This new adsorbent also showed high selectivity for the uranyl ion, and its selectivity for metal ions was found to decrease in the following order: U>Cu>Fe>Ca>Mg>Ni>Zn>Pb>V>Co. The adsorption selectivity for uranium is significantly higher than that for vanadium. In addition, preparation of this modified adsorbent consumes much smaller amounts of the toxic acrylonitrile monomer than the conventional preparation methods of AO-based polyethylene fibers.

Actin turnover maintains actin filament homeostasis during cytokinetic ring contraction

PubMed Central

Palani, Saravanan; Sommese, Ruth; Kamnev, Anton; Hatano, Tomoyuki; Sivaramakrishnan, Sivaraj

2017-01-01

Cytokinesis in many eukaryotes involves a tension-generating actomyosin-based contractile ring. Many components of actomyosin rings turn over during contraction, although the significance of this turnover has remained enigmatic. Here, using Schizosaccharomyces japonicus, we investigate the role of turnover of actin and myosin II in its contraction. Actomyosin ring components self-organize into ∼1-µm-spaced clusters instead of undergoing full-ring contraction in the absence of continuous actin polymerization. This effect is reversed when actin filaments are stabilized. We tested the idea that the function of turnover is to ensure actin filament homeostasis in a synthetic system, in which we abolished turnover by fixing rings in cell ghosts with formaldehyde. We found that these rings contracted fully upon exogenous addition of a vertebrate myosin. We conclude that actin turnover is required to maintain actin filament homeostasis during ring contraction and that the requirement for turnover can be bypassed if homeostasis is achieved artificially. PMID:28655757

The circumstellar ring of SN 1987A

NASA Astrophysics Data System (ADS)

Fransson, Claes; Migotto, Katia; Larsson, Josefin; Pesce, Dominic; Challis, Peter; Chevalier, Roger A.; France, Kevin; Kirshner, Robert P.; Leibundgut, Bruno; Lundqvist, Peter; McCray, Richard; Spyromilio, Jason; Taddia, Francesco; Jerkstrand, Anders; Mattila, Seppo; Smith, Nathan; Sollerman, Jesper; Wheeler, J. Craig; Crotts, Arlin; Garnavich, Peter; Heng, Kevin; Lawrence, Stephen S.; Panagia, Nino; Pun, Chun S. J.; Sonneborn, George; Sugerman, Ben

2016-06-01

The circumstellar ring of supernova 1987A first became visible a few months after the explosion due to photoionisation by the supernova flash. From 1995 hotspots appeared in the ring and their brightness increased nearly exponentially as a result of interaction with the supernova blast wave. Imaging and spectroscopic observations with the Hubble Space Telescope and the Very Large Telescope now show that both the shocked and the unshocked emission components from the ring have been decreasing since ~ 2009. In addition, the most recent images reveal the brightening of new spots outside the ring. These observations indicate that the hotspots are being dissolved by the shocks and that the blast wave is now expanding and interacting with dense clumps beyond the ring. Based on the currently observed decay we predict that the ring will be destroyed by ~ 2025, while the blast wave will reveal the distribution of gas as it expands outside the ring, thus tracing the mass-loss history of the supernova progenitor.

Stability of an ion-ring distribution in a multi-ion component plasma

NASA Astrophysics Data System (ADS)

Mithaiwala, Manish; Rudakov, Leonid; Ganguli, Gurudas

2010-04-01

The stability of a cold ion-ring velocity distribution in a thermal plasma is analyzed. In particular, the effect of plasma temperature and density on the instability is considered. A high ring density (compared to the background plasma) neutralizes the stabilizing effect of the warm background plasma and the ring is unstable to the generation of waves below the lower-hybrid frequency even for a very high temperature plasma. For ring densities lower than the background plasma density, there is a slow instability where the growth rate is less than the background-ion cyclotron frequency and, consequently, the background-ion response is magnetized. This is in addition to the widely discussed fast instability where the wave growth rate exceeds the background-ion cyclotron frequency and hence the background ions are effectively unmagnetized. Thus, even a low density ring is unstable to waves around the lower-hybrid frequency range for any ring speed. This implies that effectively there is no velocity threshold for a sufficiently cold ring.

The IRAF Fabry-Perot analysis package: Ring fitting

NASA Technical Reports Server (NTRS)

Shopbell, P. L.; Bland-Hawthorn, J.; Cecil, G.

1992-01-01

As introduced at ADASSI, a Fabry-Perot analysis package for IRAF is currently under development as a joint effort of ourselves and Frank Valdes of the IRAF group. Although additional portions of the package were also implemented, we report primarily on the development of a robust ring fitting task, useful for fitting the calibration rings obtained in Fabry-Perot observations. The general equation of an ellipse is fit to the shape of the rings, providing information on ring center, ellipticity, and position angle. Such parameters provide valuable information on the wavelength response of the etalon and the geometric stability of the system. Appropriate statistical weighting is applied to the pixels to account for increasing numbers with radius, the Lorentzian cross-section, and uneven illumination. The major problems of incomplete, non-uniform, and multiple rings are addressed with the final task capable of fitting rings regardless of center, cross-section, or completion. The task requires only minimal user intervention, allowing large numbers of rings to be fit in an extremely automated manner.

Michael Griffin House Science Committee Hearing

NASA Image and Video Library

2005-06-27

Members of the media photograph NASA Administrator Michael Griffin as he testifies at a hearing before the House Science Committee, Tuesday, June 28, 2005, Rayburn House Office building, Washington. Photo Credit: (NASA/Bill Ingalls)

Michael Lawson | NREL

Science.gov Websites

NREL's Ocean Energy team, Dr. Michael Lawson focuses on the areas of wave and water current energy goal of developing an open source design and analysis tool for wave energy conversion (WEC) devices

Transportation

DTIC Science & Technology

2006-01-01

Ports. Logistics Today, Vol.46. Issue 9. 43. Maloni, Michael ., Jackson , Eric. (2005, Spring). North American Container Port Capacity: A...Literature Review. Transportation Journal, Spring 2005. 16-36. Maloni, Michael ., Jackson , Eric. (2005, Summer). North American Container Port Capacity: An

DOE Office of Scientific and Technical Information (OSTI.GOV)

Banerjee, Surajit; Christov, Plamen P.; Kozekova, Albena

trans-4-Hydroxynonenal (HNE) is the major peroxidation product of {omega}-6 polyunsaturated fatty acids in vivo. Michael addition of the N{sub 2}-amino group of dGuo to HNE followed by ring closure of N1 onto the aldehyde results in four diastereomeric 1,N{sub 2}-dGuo (1,N{sub 2}-HNE-dGuo) adducts. The (6S,8R,11S)-HNE-1,N{sub 2}-dGuo adduct was incorporated into the 18-mer templates 5'-d(TCATXGAATCCTTCCCCC)-3' and d(TCACXGAATCCTTCCCCC)-3', where X = (6S,8R,11S)-HNE-1,N{sub 2}-dGuo adduct. These differed in the identity of the template 5'-neighbor base, which was either Thy or Cyt, respectively. Each of these templates was annealed with either a 13-mer primer 5'-d(GGGGGAAGGATTC)-3' or a 14-mer primer 5'-d(GGGGGAAGGATTCC)-3'. The addition of dNTPsmore » to the 13-mer primer allowed analysis of dNTP insertion opposite to the (6S,8R,11S)-HNE-1,N{sub 2}-dGuo adduct, whereas the 14-mer primer allowed analysis of dNTP extension past a primed (6S,8R,11S)-HNE-1,N{sub 2}-dGuo:dCyd pair. The Sulfolobus solfataricus P2 DNA polymerase IV (Dpo4) belongs to the Y-family of error-prone polymerases. Replication bypass studies in vitro reveal that this polymerase inserted dNTPs opposite the (6S,8R,11S)-HNE-1,N{sub 2}-dGuo adduct in a sequence-specific manner. If the template 5'-neighbor base was dCyt, the polymerase inserted primarily dGTP, whereas if the template 5'-neighbor base was dThy, the polymerase inserted primarily dATP. The latter event would predict low levels of Gua {yields} Thy mutations during replication bypass when the template 5'-neighbor base is dThy. When presented with a primed (6S,8R,11S)-HNE-1,N{sub 2}-dGuo:dCyd pair, the polymerase conducted full-length primer extension. Structures for ternary (Dpo4-DNA-dNTP) complexes with all four template-primers were obtained. For the 18-mer:13-mer template-primers in which the polymerase was confronted with the (6S,8R,11S)-HNE-1,N{sub 2}-dGuo adduct, the (6S,8R,11S)-1,N{sub 2}-dGuo lesion remained in the ring-closed conformation at the active site. The incoming dNTP, either dGTP or dATP, was positioned with Watson-Crick pairing opposite the template 5'-neighbor base, dCyt or dThy, respectively. In contrast, for the 18-mer:14-mer template-primers with a primed (6S,8R,11S)-HNE-1,N{sub 2}-dGuo:dCyd pair, ring opening of the adduct to the corresponding N{sub 2}-dGuo aldehyde species occurred. This allowed Watson-Crick base pairing at the (6S,8R,11S)-HNE-1,N{sub 2}-dGuo:dCyd pair.« less

Enhanced Performance of Perovskite CH3NH3PbI3 Solar Cell by Using CH3NH3I as Additive in Sequential Deposition.

PubMed

Xie, Yian; Shao, Feng; Wang, Yaoming; Xu, Tao; Wang, Deliang; Huang, Fuqiang

2015-06-17

Sequential deposition is a widely adopted method to prepare CH3NH3PbI3 on mesostructured TiO2 electrode for organic lead halide perovskite solar cells. However, this method often suffers from the uncontrollable crystal size, surface morphology, and residual PbI2 in the resulting CH3NH3PbI3, which are all detrimental to the device performance. We herein present an optimized sequential solution deposition method by introducing different amount of CH3NH3I in PbI2 precursor solution in the first step to prepare CH3NH3PbI3 absorber on mesoporous TiO2 substrates. The addition of CH3NH3I in PbI2 precursor solution can affect the crystallization and composition of PbI2 raw films, resulting in the variation of UV-vis absorption and surface morphology. Proper addition of CH3NH3I not only enhances the absorption but also improves the efficiency of CH3NH3PbI3 solar cells from 11.13% to 13.37%. Photoluminescence spectra suggest that the improvement of device performance is attributed to the decrease of recombination rate of carriers in CH3NH3PbI3 absorber. This current method provides a highly repeatable route for enhancing the efficiency of CH3NH3PbI3 solar cell in the sequential solution deposition method.

PSSC Turbo Ring Flinger

NASA Astrophysics Data System (ADS)

McAlexander, Aaron

2005-12-01

This is a description of an inexpensive version of the Thompson's jumping ring demonstration apparatus, which provides for a spectacular demonstration of Lenz's law. The device has the additional capability of being used to demonstrate the opposing nature of inductive and capacitive reactance.

S/He's a Rebel: Toward a Sequential Stress Theory of Delinquency and Gendered Pathways to Disadvantage in Emerging Adulthood.

ERIC Educational Resources Information Center

Hagan, John; Foster, Holly

2003-01-01

Data from the National Longitudinal Study of Adolescent Health on 11,506 high school students were used to test a gendered and age-graded sequential stress theory in which delinquency can play an additive and intervening role in adolescents' movement from early anger through rebellious or aggressive forms of behavior to later depressive symptoms…

A Longitudinal Study in Adults with Sequential Bilateral Cochlear Implants: Time Course for Individual Ear and Bilateral Performance

ERIC Educational Resources Information Center

Reeder, Ruth M.; Firszt, Jill B.; Holden, Laura K.; Strube, Michael J.

2014-01-01

Purpose: The purpose of this study was to examine the rate of progress in the 2nd implanted ear as it relates to the 1st implanted ear and to bilateral performance in adult sequential cochlear implant recipients. In addition, this study aimed to identify factors that contribute to patient outcomes. Method: The authors performed a prospective…

Rate-dependent inverse-addition beta-selective mannosylation and contiguous sequential glycosylation involving beta-mannosidic bond formation.

PubMed

Chang, Shih-Sheng; Shih, Che-Hao; Lai, Kwun-Cheng; Mong, Kwok-Kong Tony

2010-05-03

The beta-selectivity of mannosylation has been found to be dependent on the addition rate of the mannosyl trichloroacetimidate donor in an inverse-addition (I-A) procedure. This rate dependent I-A procedure can improve the selectivity of direct beta-mannosylation and is applicable to orthogonal glycosylations of thioglycoside acceptors. Further elaboration of this novel procedure enables the development of the contiguous sequential glycosylation strategy, which streamlines the preparation of oligosaccharides invoking beta-mannosidic bond formation. The synthetic utility of the contiguous glycosylation strategy was demonstrated by the preparation of the trisaccharide core of human N-linked glycoproteins and the trisaccharide repeating unit of the O-specific polysaccharide found in the cellular capsule of Salmonelle bacteria.

An improved ring removal procedure for in-line x-ray phase contrast tomography

NASA Astrophysics Data System (ADS)

Massimi, Lorenzo; Brun, Francesco; Fratini, Michela; Bukreeva, Inna; Cedola, Alessia

2018-02-01

The suppression of ring artifacts in x-ray computed tomography (CT) is a required step in practical applications; it can be addressed by introducing refined digital low pass filters within the reconstruction process. However, these filters may introduce additional ringing artifacts when simultaneously imaging pure phase objects and elements having a non-negligible absorption coefficient. Ringing originates at sharp interfaces, due to the truncation of spatial high frequencies, and severely affects qualitative and quantitative analysis of the reconstructed slices. In this work, we discuss the causes of ringing artifacts, and present a general compensation procedure to account for it. The proposed procedure has been tested with CT datasets of the mouse central nervous system acquired at different synchrotron radiation facilities. The results demonstrate that the proposed method compensates for ringing artifacts induced by low pass ring removal filters. The effectiveness of the ring suppression filters is not altered; the proposed method can thus be considered as a framework to improve the ring removal step, regardless of the specific filter adopted or the imaged sample.

An improved ring removal procedure for in-line x-ray phase contrast tomography.

PubMed

Massimi, Lorenzo; Brun, Francesco; Fratini, Michela; Bukreeva, Inna; Cedola, Alessia

2018-02-12

The suppression of ring artifacts in x-ray computed tomography (CT) is a required step in practical applications; it can be addressed by introducing refined digital low pass filters within the reconstruction process. However, these filters may introduce additional ringing artifacts when simultaneously imaging pure phase objects and elements having a non-negligible absorption coefficient. Ringing originates at sharp interfaces, due to the truncation of spatial high frequencies, and severely affects qualitative and quantitative analysis of the reconstructed slices. In this work, we discuss the causes of ringing artifacts, and present a general compensation procedure to account for it. The proposed procedure has been tested with CT datasets of the mouse central nervous system acquired at different synchrotron radiation facilities. The results demonstrate that the proposed method compensates for ringing artifacts induced by low pass ring removal filters. The effectiveness of the ring suppression filters is not altered; the proposed method can thus be considered as a framework to improve the ring removal step, regardless of the specific filter adopted or the imaged sample.

Daylighting in the Springfield (Ohio) Museum of Art

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moore, F.

This paper describes daylighting strategies used in the addition to the Springfield Museum of Art, Springfield, Ohio. The interior daylighting illuminances and luminances have been measured and these data are presented. The original museum was built in 1958. This original portion is approximately 18,000 ft{sup 2} (1,674 m{sup 2}) floor area and was remodeled as part of the 1995 addition to house and art school, cataloging, preparation, and administrative functions. The new addition is approximately 10,000 ft{sup 2} (930 m{sup 2}) and is primarily exhibit galleries with some additional administrative offices. Glaser Associated were the architects (Michael Moose, project architect)more » and the author was the daylighting consultant on the project.« less

Comparison of solution-mixed and sequentially processed P3HT: F4TCNQ films: effect of doping-induced aggregation on film morphology

DOE PAGES

Jacobs, Ian E.; Aasen, Erik W.; Oliveira, Julia L.; ...

2016-03-23

Doping polymeric semiconductors often drastically reduces the solubility of the polymer, leading to difficulties in processing doped films. Here, we compare optical, electrical, and morphological properties of P3HT films doped with F4TCNQ, both from mixed solutions and using sequential solution processing with orthogonal solvents. We demonstrate that sequential doping occurs rapidly (<1 s), and that the film doping level can be precisely controlled by varying the concentration of the doping solution. Furthermore, the choice of sequential doping solvent controls whether dopant anions are included or excluded from polymer crystallites. Atomic force microscopy (AFM) reveals that sequential doping produces significantly moremore » uniform films on the nanoscale than the mixed-solution method. In addition, we show that mixed-solution doping induces the formation of aggregates even at low doping levels, resulting in drastic changes to film morphology. Sequentially coated films show 3–15 times higher conductivities at a given doping level than solution-doped films, with sequentially doped films processed to exclude dopant anions from polymer crystallites showing the highest conductivities. In conclusion, we propose a mechanism for doping induced aggregation in which the shift of the polymer HOMO level upon aggregation couples ionization and solvation energies. To show that the methodology is widely applicable, we demonstrate that several different polymer:dopant systems can be prepared by sequential doping.« less

Comparison of solution-mixed and sequentially processed P3HT: F4TCNQ films: effect of doping-induced aggregation on film morphology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jacobs, Ian E.; Aasen, Erik W.; Oliveira, Julia L.

Doping polymeric semiconductors often drastically reduces the solubility of the polymer, leading to difficulties in processing doped films. Here, we compare optical, electrical, and morphological properties of P3HT films doped with F4TCNQ, both from mixed solutions and using sequential solution processing with orthogonal solvents. We demonstrate that sequential doping occurs rapidly (<1 s), and that the film doping level can be precisely controlled by varying the concentration of the doping solution. Furthermore, the choice of sequential doping solvent controls whether dopant anions are included or excluded from polymer crystallites. Atomic force microscopy (AFM) reveals that sequential doping produces significantly moremore » uniform films on the nanoscale than the mixed-solution method. In addition, we show that mixed-solution doping induces the formation of aggregates even at low doping levels, resulting in drastic changes to film morphology. Sequentially coated films show 3–15 times higher conductivities at a given doping level than solution-doped films, with sequentially doped films processed to exclude dopant anions from polymer crystallites showing the highest conductivities. In conclusion, we propose a mechanism for doping induced aggregation in which the shift of the polymer HOMO level upon aggregation couples ionization and solvation energies. To show that the methodology is widely applicable, we demonstrate that several different polymer:dopant systems can be prepared by sequential doping.« less

Michael Additions of Highly Basic Enolates to ortho-Quinone Methides

PubMed Central

Lewis, Robert S.; Garza, Christopher J.; Dang, Ann T.; Pedro, Te Kie A.; Chain, William J.

2015-01-01

A protocol by which ketone or ester enolates and ortho-quinone methides (o-QMs) are generated in situ in a single reaction flask from silylated precursors under the action of anhydrous fluoride is reported. The reaction partners are joined to give a variety of β-(2-hydroxyphenyl)-carbonyl compounds in 32–94% yield in a single laboratory operation. The intermediacy of o-QMs is supported by control experiments utilizing enolate precursors and conventional alkyl halides as competitive alkylating agents and the isolation of 1,5-dicarbonyl products resulting from conjugate additions that do not restore the aromatic system. PMID:25906358

Convex functions and some inequalities in terms of the Non-Newtonian Calculus

NASA Astrophysics Data System (ADS)

Unluyol, Erdal; Salas, Seren; Iscan, Imdat

2017-04-01

Differentiation and integration are basic operations of calculus and analysis. Indeed, they are many versions of the subtraction and addition operations on numbers, respectively. From 1967 till 1970 Michael Grossman and Robert Katz [1] gave definitions of a new kind of derivative and integral, converting the roles of subtraction and addition into division and multiplication, and thus establish a new calculus, called Non-Newtonian Calculus. So, in this paper, it is investigated to the convex functions and some inequalities in terms of Non-Newtonian Calculus. Then we compare with the Newtonian and Non-Newtonian Calculus.

2-Nitro-thioglycosides: α- and β-selective generation and their potential as β-selective glycosyl donors.

PubMed

Peng, Peng; Geng, Yiqun; Göttker-Schnetmann, Inigo; Schmidt, Richard R

2015-03-20

Michael-type addition of thiolates to 2-nitro-D-glucal or to 2-nitro-D-galactal derivatives readily provides 2-deoxy-2-nitro-1-thioglycosides. Kinetic and thermodynamic reaction control permitted formation of either the α- or preferentially the β-anomers, respectively. Addition of achiral and chiral thiourea derivatives to the reaction mixture increased the reaction rate; the outcome is substrate-controlled. The 2-deoxy-2-nitro-1-thioglycosides are excellent glycosyl donors under arylsulfenyl chloride/silver triflate (ArSCl/AgOTf) activation, and they provide, anchimerically assisted by the nitro group, mostly β-glycosides.

Automated podosome identification and characterization in fluorescence microscopy images.

PubMed

Meddens, Marjolein B M; Rieger, Bernd; Figdor, Carl G; Cambi, Alessandra; van den Dries, Koen

2013-02-01

Podosomes are cellular adhesion structures involved in matrix degradation and invasion that comprise an actin core and a ring of cytoskeletal adaptor proteins. They are most often identified by staining with phalloidin, which binds F-actin and therefore visualizes the core. However, not only podosomes, but also many other cytoskeletal structures contain actin, which makes podosome segmentation by automated image processing difficult. Here, we have developed a quantitative image analysis algorithm that is optimized to identify podosome cores within a typical sample stained with phalloidin. By sequential local and global thresholding, our analysis identifies up to 76% of podosome cores excluding other F-actin-based structures. Based on the overlap in podosome identifications and quantification of podosome numbers, our algorithm performs equally well compared to three experts. Using our algorithm we show effects of actin polymerization and myosin II inhibition on the actin intensity in both podosome core and associated actin network. Furthermore, by expanding the core segmentations, we reveal a previously unappreciated differential distribution of cytoskeletal adaptor proteins within the podosome ring. These applications illustrate that our algorithm is a valuable tool for rapid and accurate large-scale analysis of podosomes to increase our understanding of these characteristic adhesion structures.

Enhancement of photoacoustic tomography by ultrasonic computed tomography based on optical excitation of elements of a full-ring transducer array.

PubMed

Xia, Jun; Huang, Chao; Maslov, Konstantin; Anastasio, Mark A; Wang, Lihong V

2013-08-15

Photoacoustic computed tomography (PACT) is a hybrid technique that combines optical excitation and ultrasonic detection to provide high-resolution images in deep tissues. In the image reconstruction, a constant speed of sound (SOS) is normally assumed. This assumption, however, is often not strictly satisfied in deep tissue imaging, due to acoustic heterogeneities within the object and between the object and the coupling medium. If these heterogeneities are not accounted for, they will cause distortions and artifacts in the reconstructed images. In this Letter, we incorporated ultrasonic computed tomography (USCT), which measures the SOS distribution within the object, into our full-ring array PACT system. Without the need for ultrasonic transmitting electronics, USCT was performed using the same laser beam as for PACT measurement. By scanning the laser beam on the array surface, we can sequentially fire different elements. As a first demonstration of the system, we studied the effect of acoustic heterogeneities on photoacoustic vascular imaging. We verified that constant SOS is a reasonable approximation when the SOS variation is small. When the variation is large, distortion will be observed in the periphery of the object, especially in the tangential direction.

A mapping variable ring polymer molecular dynamics study of condensed phase proton-coupled electron transfer

NASA Astrophysics Data System (ADS)

Pierre, Sadrach; Duke, Jessica R.; Hele, Timothy J. H.; Ananth, Nandini

2017-12-01

We investigate the mechanisms of condensed phase proton-coupled electron transfer (PCET) using Mapping-Variable Ring Polymer Molecular Dynamics (MV-RPMD), a recently developed method that employs an ensemble of classical trajectories to simulate nonadiabatic excited state dynamics. Here, we construct a series of system-bath model Hamiltonians for the PCET, where four localized electron-proton states are coupled to a thermal bath via a single solvent mode, and we employ MV-RPMD to simulate state population dynamics. Specifically, for each model, we identify the dominant PCET mechanism, and by comparing against rate theory calculations, we verify that our simulations correctly distinguish between concerted PCET, where the electron and proton transfer together, and sequential PCET, where either the electron or the proton transfers first. This work represents a first application of MV-RPMD to multi-level condensed phase systems; we introduce a modified MV-RPMD expression that is derived using a symmetric rather than asymmetric Trotter discretization scheme and an initialization protocol that uses a recently derived population estimator to constrain trajectories to a dividing surface. We also demonstrate that, as expected, the PCET mechanisms predicted by our simulations are robust to an arbitrary choice of the initial dividing surface.

Employment programs and professionals with a disability.

PubMed

Donelly, Michelle; Given, Fiona

2010-01-01

It is unclear whether or not open (competitive) employment programs are meeting the needs of the growing numbers of people with a disability seeking professional employment. To understand and describe the experience of a newly graduated professional (Michael) who was seeking open employment support and to analyze those experiences in relation to principles of effective open employment support. Michael a recently graduated accountant who also has a physical disability. A review of the literature was undertaken to identify recommended principles and practices for the conduct of effective open employment and career development programs. A case study was used to describe Michael's experiences as he sought professional employment. Michael's experiences were analysed in relation to recommended principles and practice. The analysis confirmed that the concerns Michael experienced about the supported employment program compromised the effectiveness of the support he received. Employment services based on models of independent living, disability service standards and remediation are likely to focus on the 'pathology' or performance 'deficits' of the person with a disability. Successful open employment models are more likely to place pre-eminence on the perspective of the person with a disability and effective practices for securing employment.

Environmental Fate of 14C Radiolabeled 2,4-Dinitroanisole in Soil Microcosms.

PubMed

Olivares, Christopher I; Madeira, Camila L; Sierra-Alvarez, Reyes; Kadoya, Warren; Abrell, Leif; Chorover, Jon; Field, Jim A

2017-11-21

2,4-Dinitrosanisole (DNAN) is an insensitive munitions component replacing conventional explosives. While DNAN is known to biotransform in soils to aromatic amines and azo-dimers, it is seldom mineralized by indigenous soil bacteria. Incorporation of DNAN biotransformation products into soil as humus-bound material could serve as a plausible remediation strategy. The present work studied biotransformation of DNAN in soil and sludge microcosms supplemented with uniformly ring-labeled 14 C-DNAN to quantify the distribution of label in soil, aqueous, and gaseous phases. Electron donor amendments, different redox conditions (anaerobic, aerobic, sequential anaerobic-aerobic), and the extracellular oxidoreductase enzyme horseradish peroxidase (HRP) were evaluated to maximize incorporation of DNAN biotransformation products into the nonextractable soil humus fraction, humin. Irreversible humin incorporation of 14 C-DNAN occurred at higher rates in anaerobic conditions, with a moderate increase when pyruvate was added. Additionally, a single dose of HRP resulted in an instantaneous increased incorporation of 14 C-DNAN into the humin fraction. 14 C-DNAN incorporation to the humin fraction was strongly correlated (R 2 = 0.93) by the soil organic carbon (OC) amount present (either intrinsic or amended). Globally, our results suggest that DNAN biotransformation products can be irreversibly bound to humin in soils as a remediation strategy, which can be enhanced by adding soil OC.

Separation of mutagenic components in synthetic crudes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guerin, M. R.; Ho, C. H.; Clark, B. R.

1978-01-01

Mutagenic, basic constituents of a synthetic coal oil and a shale oil were isolated from the crude mixtures. In arriving at an efficient isolation procedure, several liquid chromatographic packing-eluent combinations were tried and the fractions bioassayed to determine the distributions of the mutagenic components. The most effective separation was achieved using a sequential elution scheme with first an alumina-benzene combination followed by a Sephadex LH-20 gel-isopropanol-acetone system. About 75 to 80% of an ether soluble base is eluted with benzene through alumina (activity I). Analysis of this fraction has revealed a wide range of alkyl substituted quinolines and pyridines. Materialmore » remaining on the alumina column was eluted with ethanol, dried and placed on the Sephadex column. Isopropanol (approximately 250 ml) and acetone (approximately 600 ml) were used in that order to elute the material quantitatively. About 12% of the ether-soluble base is eluted with the isopropanol while the rest (approximately 10%) is eluted with the acetone. Additional alkyl pyridine compounds are eluted with isopropanol while the acetone fractions are predominantly multi-ring nitrogen heterocyclic compounds, according to mass spectral analyses. Bioassay data show excellent isolation of the mutagenic activities into the acetone fractions. Negligible activity is found in the sum of the other (90% wt) fractions.« less

Deuterium and carbon-13 NMR of the solid polymorphism of benzenehexoyl hexa-n-hexanoate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lifshitz, E.; Goldfarb,, D.; Vega, S.

Deuterium and carbon-13 NMR of specifically labeled benzenehexoyl hexa-n-hexanoate in the various solid-state phases are reported. The spectra exhibit dynamic line shapes which change discontinuously at the phase transitions. The results are interpreted in terms of sequential melting of the side chains on going from the low-temperature solid phases IV, III, etc., toward the liquid. In phase IV the molecules are very nearly static, except for fast rotation of the methyl groups about their C/sub 3/ axes. The results in phase III were quantitatively interpreted in terms of a two-site isomerization process involving simultaneous rotation by 95/sup 0/ about C/submore » 1/-C/sub 2/ and transition from gtg to g'g't (or equivalently g'tg' to ggt) for the rest of the chain. The specific rate of this reaction at 0/sup 0/C is approx. 10/sup 5/s/sup -1/. In phase II additional chain isomerization processes set-in which were, however, not analyzed quantitatively. Further motional modes, involving reorientation of whole chains about their C/sup ar/-O bonds, appear on going to phase I. In all solid phases the benzene ring remains static.« less

Meet EPA Scientist Michael Nye, Ph.D.

EPA Pesticide Factsheets

Michael Nye, Ph.D., is a social scientist who studies natural risk, socio-demographic change and sustainable behavior. Prior to joining EPA, he worked for the UK Environment Agency in flood risk management and emergency preparedness

On the tidal environment of an outwardly migrating F ring

NASA Astrophysics Data System (ADS)

Sutton, Phil J.

2018-07-01

Saturn's F ring is a unique narrow ring that lies (radially) close to the tidally disruptive Roche limit of water ice for Saturn. Significant work has been done that shows it to be one of the most dynamic places in the Solar system. Aggregates that are fortunate enough to form constantly battle against the strong tidal forces of Saturn and the nearby moons Prometheus and Pandora, which act to gravitationally stir up ring material. Planetary rings are also known to radially spread. Therefore, as the F ring lies at the edge of the main rings, we investigate the effect of an outwardly migrated F ring and its interaction with Prometheus. An increase in the maximum number density of particles at the channel edges is observed with decreasing local tidal environment. Radial velocity dispersions are also observed to fall below the typical escape velocity of a 150 m icy moonlet (<10 cm s^{-1}) where density is enhanced, and are gravitationally unstable with Toomre parameters Q < 2. Additionally, in locations of the ring where Q < 2 is observed, more particles are seen to fall below or close to the critical Toomre parameter as the radial location of the ring increases.

Thin Film Thermoelectric Metal-Organic Framework with High Seebeck Coefficient and Low Thermal Conductivity. Supporting Information

DTIC Science & Technology

2015-04-28

François Léonard, Vitalie Stavila, Michael E. Foster, Catalin D. Spataru, Reese E. Jones, Brian M. Foley, Patrick E. Hopkins, Mark D. Allendorf, A. Alec...Léonard, Vitalie Stavila, Michael E. Foster, Catalin D. Spataru, Reese E. Jones, Brian M. Foley, Patrick E. Hopkins, Mark D. Allendorf, and A. Alec Talin...Kristopher J. Erickson, François Léonard, Vitalie Stavila, Michael E. Foster, Catalin D. Spataru, Reese E. Jones, Brian M. Foley, Patrick E. Hopkins, Mark D

Biennial Guidance Test Symposium (16th) Held in Holloman Air Force Base, New Mexico on October 5-7, 1993. Volume 1

DTIC Science & Technology

1993-10-01

Michael Swamp, Contraves Inc., Pittsburgh PA; Dr. Michael D. Hooser, CIGTF, Holloman AFB NM Hig h Stability Large Centrifuge Test Bed 305 Dr. Louis A...DeMore, Robert Anticole, and Hans Riggenbach, Contraves Inc, Pittsburgh PA; Dr. Michael D. Hooser, CIGTF, Holloman AFB NM vi SESSION V-A: WEAPONS...power spectral density of input are also frozen out, allowing very low loss referred noise) of 10’ HzŖ below 100 Hz. springs. The input coils are

Causes of Ring-Related Leg Injuries in Birds – Evidence and Recommendations from Four Field Studies

PubMed Central

Griesser, Michael; Schneider, Nicole A.; Collis, Mary-Anne; Overs, Anthony; Guppy, Michael; Guppy, Sarah; Takeuchi, Naoko; Collins, Pete; Peters, Anne; Hall, Michelle L.

2012-01-01

One of the main techniques for recognizing individuals in avian field research is marking birds with plastic and metal leg rings. However, in some species individuals may react negatively to rings, causing leg injuries and, in extreme cases, the loss of a foot or limb. Here, we report problems that arise from ringing and illustrate solutions based on field data from Brown Thornbills (Acanthiza pusilla) (2 populations), Siberian Jays (Perisoreus infaustus) and Purple-crowned Fairy-wrens (Malurus coronatus). We encountered three problems caused by plastic rings: inflammations triggered by material accumulating under the ring (Purple-crowned Fairy-wrens), contact inflammations as a consequence of plastic rings touching the foot or tibio-tarsal joint (Brown Thornbills), and toes or the foot getting trapped in partly unwrapped flat-band colour rings (Siberian Jays). Metal rings caused two problems: the edges of aluminium rings bent inwards if mounted on top of each other (Brown Thornbills), and too small a ring size led to inflammation (Purple-crowned Fairy-wrens). We overcame these problems by changing the ringing technique (using different ring types or larger rings), or using different adhesive. Additionally, we developed and tested a novel, simple technique of gluing plastic rings onto metal rings in Brown Thornbills. A review of studies reporting ring injuries (N = 23) showed that small birds (<55 g body weight) are more prone to leg infections while larger birds (>35 g) tend to get rings stuck over their feet. We give methodological advice on how these problems can be avoided, and suggest a ringing hazard index to compare the impact of ringing in terms of injury on different bird species. Finally, to facilitate improvements in ringing techniques, we encourage online deposition of information regarding ringing injuries of birds at a website hosted by the European Union for Bird Ringing (EURING). PMID:23300574

Evaporation of sessile drops containing colloidal rods: coffee-ring and order-disorder transition.

PubMed

Dugyala, Venkateshwar Rao; Basavaraj, Madivala G

2015-03-05

Liquid drops containing insoluble solutes when dried on solid substrates leave distinct ring-like deposits at the periphery or along the three-phase contact line-a phenomena popularly known as the coffee-ring or the coffee stain effect. The formation of such rings as well as their suppression is shown to have applications in particle separation and disease diagnostics. We present an experimental study of the evaporation of sessile drops containing silica rods to elucidate the structural arrangement of particles in the ring, an effect of the addition of surfactant and salt. To this end, the evaporation of aqueous sessile drops containing model rod-like silica particles of aspect ratio ranging from ∼4 to 15 on a glass slide is studied. We first show that when the conditions such as (1) solvent evaporation, (2) nonzero contact angle, (3) contact line pinning, (4) no surface tension gradient driven flow, and (5) repulsive particle-particle/particle-substrate interactions, that are necessary for the formation of the coffee-ring are met, the suspension drops containing silica rods upon evaporation leave a ring-like deposit. A closer examination of the ring deposits reveals that several layers of silica rods close to the edge of the drop are ordered such that the major axis of the rods are oriented parallel to the contact line. After the first few layers of ordered arrangement of particles, a random arrangement of particles in the drop interior is observed indicating an order-disorder transition in the ring. We monitor the evolution of the ring width and particle velocity during evaporation to elucidate the mechanism of the order-disorder transition. Moreover, when the evaporation rate is lowered, the ordering of silica rods is observed to extend over large areas. We demonstrate that the nature of the deposit can be tuned by the addition of a small quantity of surfactant or salt.

Upgrade/Renovate Clinic Project at Ellsworth Air Force Base, South Dakota Generally Complied with the American Recovery and Reinvestment Act

DTIC Science & Technology

2011-01-06

extended to the staff. Please direct questions to Mr. Michael Joseph at (757) 872-4698. Alice F. Carey Assistant Inspector General Readiness...optometry, dental , flight medicine, mental health, physical therapy, laboratory, pharmacy, and radiology. 3 Project Support Personnel at USACE...plan, dental equipment revisions, a corridor addition, replacement of all basement piping, and $3,374,672 of Operations and Maintenance funds

Theory to Strategy: War Insight for the Strategic Soldier

DTIC Science & Technology

2008-05-22

Library Typography , New York, 1993, 162. 3 Additionally, these models may provide insights as to what an adversary may do depending on the nature of...11. 7 Carl Von Clausewitz, On War (edited and translated by Michael Howard and Peter Paret), Everyman’s Library Typography , New York, 1993, 73...Paret), Everyman’s Library Typography , New York, 1993, 88. 8 common enemy. Minimizing the amount of allies an adversary has may also limit its

Damage Control Resuscitation: Directly Addressing the Early Coagulopathy of Trauma

DTIC Science & Technology

2007-02-01

FACS, Jay Johannigman, MD, FS, FACS, Peter Mahoney, FRCA, RAMC , Sumeru Mehta, MD, E. Darrin Cox, MD, FACS, Michael J. Gehrke, MD, Greg J. Beilman, MD...opportunity to formally evaluate the immediate and direct treatment of the coagulopathy of trauma is available. Submitted for publication September 22, 2006...the results were not evaluated in randomized human trials.33–35 Additionally, the potential benefits of mitigating ischemia-induced reperfusion injury

Cassini RADAR End of Mission Calibration and Preliminary Ring Results

NASA Astrophysics Data System (ADS)

West, R. D.; Janssen, M.; Zhang, Z.; Cuzzi, J. N.; Anderson, Y.; Hamilton, G.

2017-12-01

The Cassini mission is in the midst of its last year of observations. Part of the mission plan includes orbits that bring the spacecraft close to Saturn's rings prior to deorbiting into Saturn's atmosphere. First, a series of F-ring orbits crossed the ring plane just outside of the F-ring, and then a series of Proximal orbits crossed the ring plane inside of the D-ring - just above the cloud tops. The Cassini RADAR instrument collected active and passive data of the rings in 5 observations, of Saturn in one observation, and passive only data in an additional 4 observations. These observations provided a unique opportunity to obtain backscatter measurements and relatively high-resolution brightness temperature measurements from Saturn and the rings. Such measurements were never before possible from the spacecraft or the Earth due to high range. Before the F-ring orbits began, and again during the last rings scan, the radar collected calibration data to aid calibration of the rings measurements and to provide an updated timeline of the radar calibration over the whole mission. This presentation will cover preliminary processing results from the radar rings scans and from the calibration data sets. Ultimately, these ring scan measurements will provide a 1-D profile of backscatter obtained at 2.2 cm wavelength that will complement similar passive profiles obtained at optical, infrared, and microwave wavelengths. Such measurements will further constrain and inform models of the ring particle composition and structure, and the local vertical structure of the rings. This work is supported by the NASA Cassini Program at JPL - CalTech.

Parametric design analysis of a hybrid composite flywheel using a laminated central disc and a filament wound outer ring

NASA Astrophysics Data System (ADS)

Nimmer, R. P.

1980-09-01

A hybrid flywheel design concept based on the use of a laminated central disk with a filament-wound outer ring is analyzed for several different combinations of composite materials. Some of the results of this study are: (1) an optimized E-glass disk with Kevlar-49 outer ring offers the prospect of 30% additional energy density over a laminated disk without a ring; (2) a laminated S2-glass disk is capable of storing more energy per unit mass than an E-glass disk because of its higher tensile strength; and (3) the use of wound graphite outer rings with S2-glass disks leads to substantial reductions in the size of the interference fit while offering still higher energy densities than for a Kevlar-49 outer ring.

RING-type E3 ligases: Master manipulators of E2 ubiquitin-conjugating enzymes and ubiquitination

PubMed Central

Metzger, Meredith B.; Pruneda, Jonathan N.; Klevit, Rachel E.; Weissman, Allan M.

2013-01-01

RING finger domain and RING finger-like ubiquitin ligases (E3s), such as U-box proteins, constitute the vast majority of known E3s. RING-type E3s function together with ubiquitin-conjugating enzymes (E2s) to mediate ubiquitination and are implicated in numerous cellular processes. In part because of their importance in human physiology and disease, these proteins and their cellular functions represent an intense area of study. Here we review recent advances in RING-type E3 recognition of substrates, their cellular regulation, and their varied architecture. Additionally, recent structural insights into RING-type E3 function, with a focus on important interactions with E2s and ubiquitin, are reviewed. This article is part of a Special Issue entitled: Ubiquitin-Proteasome System. PMID:23747565

Effect of N-acetylcysteine on vascular endothelium function in aorta from oophorectomized rats.

PubMed

Delgado, J L; Landeras, J; Carbonell, L F; Parilla, J J; Abad, L; Quesada, T; Fiol, G; Hernández, I

1999-01-01

1. Experiments were performed to examine and to compare vascular endothelial function in aortic rings from oophorectomized and from ovary-intact rats and to test the effect of thiol compound as N-acetylcysteine on endothelial function. 2. In precontracted aortic rings from oophorectomized and intact rats, vascular endothelial function was evaluated by measuring changes in isometric force in response to cumulative doses of superoxide dismutase, acetylcholine and sodium nitroprusside. 3. In studies designed to assess the tone-related release of nitric oxide from aortic rings moderately precontracted with phenylephrine, superoxide dismutase produced a lower concentration-related relaxant response in aortic rings from oophorectomized rats than from ovary intact rats. 4. Acetylcholine caused a concentration- and endothelium-dependent relaxation of less magnitude in aortic rings from oophorectomized animals compared with those from ovary-intact rats. Addition of N-omega-nitro-L-arginine methyl ester eliminated the relaxation induced by both superoxide dismutase and acetylcholine. 5. No differences between groups were noticed in the concentration-relaxation curve induced by sodium nitroprusside. 6. Preincubation with N-acetylcysteine normalized the depressed vasorelaxant response to acetylcholine in the aortic rings from oophorectomized rats, whereas the concentration-response curve for acetylcholine in aortic rings from ovary-intact rats did not alter. 7. These results suggest that the absence of ovary estrogens is associated with a vascular endothelium dysfunction that can be reverted by addition of N-acetylcysteine, a thiol-containing compound with a free radical scavenger effect.

Comparing CTH Simulations and Experiments on Explosively Loaded Rings

NASA Astrophysics Data System (ADS)

Braithwaite, C. H.; Aydelotte, B.; Thadhani, N. N.; Williamson, D. M.

2011-06-01

A series of experiments were conducted on explosively loaded rings for the purpose of studying fragmentation. In addition to the collection of fragments for analysis, the radial velocity of the expanding ring was measured with PDV and the arrangement was imaged using a high speed camera. Both the ring material and the material used as the explosive container were altered and the results compared with simulations performed in CTH. Good agreement was found between the simulations and the experiments. The maximum radial velocity attained was approximately 450 m/s, which was achieved through loading with a 5g PETN based charge.

Does Saturn have rings outside 10 R(s)?

NASA Technical Reports Server (NTRS)

Cheng, A. F.; Lanzerotti, L. J.; Maclennan, C. G.

1985-01-01

Voyager ion and electron data in the energy range 30-1000 keV as measured by the Low Energy Charged Particle experiment are reviewed to check suggestions based on star occultation data that there are additional tenuous rings of Saturn beyond 10 Saturn radii from that planet. In the Voyager data, there is no convincing evidence for such ring matter. Features in the charged particle fluxes in the regions in question are more readily explained by temporal variations and/or spatial structure unrelated to ring matter, such as the mantle on the dayside and/or detached plasma sheets.

2,4 Diamino benzonitrile

NASA Technical Reports Server (NTRS)

Frost, Lawrence W. (Inventor)

1980-01-01

Deep curable polymers having heterocyclic ring systems such as isoindoloquinazolinedione ring systems prepared from novel cyanoimide polymers, most desirably 2'-cyanoimide polymers. Preferably the cyanoimide polymers are prepared from a diamine having at least one nitrile group in the two position to an amine group and a dianhydride having at least two cyclic anhydride groups. Copolymers may be prepared having other linkages, notably imide linkages, in addition to isoindoloquinazolinedione ring systems and/or other similar heterocyclic ring systems. The copolymers can be prepared by use of diamines containing one or more cyanoimide groupings and/or imide groups in their structure.

Utilizing wheel-ring architecture for stable and selectable single-longitudinal-mode erbium fiber laser

NASA Astrophysics Data System (ADS)

Yeh, Chien-Hung; Yang, Zi-Qing; Huang, Tzu-Jung; Chow, Chi-Wai

2018-03-01

To achieve a steady single-longitudinal-mode (SLM) erbium-doped fiber (EDF) laser, the wheel-ring architecture is proposed in the laser cavity. According to Vernier effect, the proposed wheel-ring can produce three different free spectrum ranges (FSRs) to serve as the mode-filter for suppressing the densely multi-longitudinal-mode (MLM). Here, to complete wavelength-tunable EDF laser, an optical tunable bandpass filter (OTBF) is utilized inside the cavity for tuning arbitrarily. In addition, the entire output performances of the proposed EDF wheel-ring laser are also discussed and analyzed experimentally.

Laparoscopic-assisted extracorporeal ovarian cystectomy: a new technique.

PubMed

Ikuma, Kenichino; Amin, Magdy; Yukio, Yamada; Hisato, Okuo; Yoshihiro, Ito; Shintaro, Ueda; Masako, Tanaka; Yasuki, Koyasu

2004-01-01

An increasing number of adnexal masses are currently managed laparoscopically, which has hampered progress regarding the different techniques of laparoscopic surgery. In this chapter, a modified application of surgical instrument was described in laparoscopic ovarian cystectomy-we named this device, Lap-Disc Mini. This new instrument has three rings, an inner flexible ring fixed to a middle ring by a rubber corset, and an additional dynamic outer ring that has a rubbery-like iris opening, which allows the application of different-sized trocars and extracorporeal ovarian cystectomy. This technique has proved to be effective and safe, especially in removing large ovarian cyst.

Book review: Black bass diversity: Multidisciplinary science for conservation

USGS Publications Warehouse

Jelks, Howard L.

2016-01-01

Review info: Black bass diversity: Multidisciplinary science for conservation. Edited by Michael D. Tringali, James M. Long, Timothy W. Birdsong, and Michael S. Allen, 2015. ISBN: 978-1-934874-40-0, 685 pp.

MIDWEST STRUCTURAL SCIENCES CENTER 2011 ANNUAL REPORT

DTIC Science & Technology

2011-10-01

S. MICHAEL SPOTTSWOOD MICHAEL J. SHEPARD , Chief Senior Aerospace Engineer Analytical Mechanics Branch Analytical...49th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics & Materials Confe- rence, Chicago , IL, Apr. 7-10, 2008. AIAA 2008-2077. Efstathiou C

76 FR 25378 - Arts and Artifacts Indemnity Panel Advisory; Committee

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-04

... Officer, Michael McDonald, 1100 Pennsylvania Avenue, NW., Washington, DC 20506, or call 202/606-8322. Michael P. McDonald, Management Officer, Advisory Committee. [FR Doc. 2011-10789 Filed 5-3-11; 8:45 am...

Michael Akam and the rise of evolutionary developmental biology

PubMed Central

Stern, David L.; Dawes-Hoang, Rachel E.

2010-01-01

Michael Akam has been awarded the 2007 Kowalevsky medal for his many research accomplishments in the area of evolutionary developmental biology. We highlight three tributaries of Michael’s contribution to evolutionary developmental biology. First, he has made major contributions to our understanding of development of the fruit fly, Drosophila melanogaster. Second, he has maintained a consistent focus on several key problems in evolutionary developmental biology, including the evolving role of Hox genes in arthropods and, more recently, the evolution of segmentation mechanisms. Third, Michael has written a series of influential reviews that have integrated progress in developmental biology into an evolutionary perspective. Michael has also made a large impact on the field through his effective mentorship style, his selfless promotion of younger colleagues, and his leadership of the University Museum of Zoology at Cambridge and the European community of evolutionary developmental biologists. PMID:20209429

Mechanical improvement of metal reinforcement rings for a finite ring-shaped superconducting bulk

NASA Astrophysics Data System (ADS)

Huang, Chen-Guang; Zhou, You-He

2018-03-01

As a key technique, reinforcement of type-II superconducting bulks with metal rings can efficiently improve their mechanical properties to enhance the maximum trapped field. In this paper, we study the magnetostrictive and fracture behaviors of a finite superconducting ring bulk reinforced by three typical reinforcing structures composed of metal rings during the magnetizing process by means of the minimization of magnetic energy and the finite element method. After a field-dependent critical current density is adopted, the magnetostriction, pinning-induced stress, and crack tip stress intensity factor are calculated considering the demagnetization effects. The results show that the mechanical properties of the ring bulk are strongly dependent on the reinforcing structure and the material and geometrical parameters of the metal rings. Introducing the metal ring can significantly reduce the hoop stress, and the reduction effect by internal reinforcement is much improved relative to external reinforcement. By comparison, bilateral reinforcement seems to be the best candidate structure. Only when the metal rings have particular Young's modulus and radial thickness will they contribute to improve the mechanical properties the most. In addition, if an edge crack is pre-existing in the ring bulk, the presence of metal rings can effectively avoid crack propagation since it reduces the crack tip stress intensity factor by nearly one order of magnitude.