Antiviral acyclic nucleoside phosphonates: New structures and prodrugs

Czech Academy of Sciences Publication Activity Database

Krečmerová, Marcela; Tichý, Tomáš; Pomeisl, Karel; Andrei, G.; Balzarini, J.; Snoeck, R.

2016-01-01

Roč. 1, č. 2 (2016), s. 37 [PharmaMed-2016. International Conference on Medicinal and Pharmaceutical Chemistry . 05.12.2016-07.12.2016, Dubai] R&D Projects: GA ČR(CZ) GA14-00522S Institutional support: RVO:61388963 Keywords : acyclic nucleoside phosphonates * prodrugs * antivirals * 5-azacytosine Subject RIV: CC - Organic Chemistry

Wavelet entropy and directed acyclic graph support vector machine for detection of patients with unilateral hearing loss in MRI scanning

Directory of Open Access Journals (Sweden)

Shuihua Wang

2016-10-01

Full Text Available (Aim Sensorineural hearing loss (SNHL is correlated to many neurodegenerative disease. Now more and more computer vision based methods are using to detect it in an automatic way. (Materials We have in total 49 subjects, scanned by 3.0T MRI (Siemens Medical Solutions, Erlangen, Germany. The subjects contain 14 patients with right-sided hearing loss (RHL, 15 patients with left-sided hearing loss (LHL, and 20 healthy controls (HC. (Method We treat this as a three-class classification problem: RHL, LHL, and HC. Wavelet entropy (WE was selected from the magnetic resonance images of each subjects, and then submitted to a directed acyclic graph support vector machine (DAG-SVM. (Results The 10 repetition results of 10-fold cross validation shows 3-level decomposition will yield an overall accuracy of 95.10% for this three-class classification problem, higher than feedforward neural network, decision tree, and naive Bayesian classifier. (Conclusions This computer-aided diagnosis system is promising. We hope this study can attract more computer vision method for detecting hearing loss.

NMR studies of abasic sites in DNA duplexes: Deoxyadenosine stacks into the helix opposite acyclic lesions

International Nuclear Information System (INIS)

Kalnik, M.W.; Chang, Chienneng; Johnson, F.; Grollman, A.P.; Patel, D.J.

1989-01-01

Proton and phosphorus NMR studies are reported for two complementary nonanucleotide duplexes containing acyclic abasic sites. The first duplex, d(C-A-T-G-A-G-T-A-C)·d(G-T-A-C-P-C-A-T-G), contains an acyclic propanyl moiety, P, located opposite a deoxyadenosine at the center of the helix (designated AP P 9-mer duplex). The second duplex, d(C-A-T-G-A-G-T-A-C-)·d(G-T-A-C-E-C-A-T-G), contains a similarly located acyclic ethanyl moiety, E (designated AP E 9-mer duplex). The ethanyl moiety is one carbon shorter than the natural carbon-phosphodiester backbone of a single nucleotide unit of DNA. The majority of the exchangeable and nonexchangeable base and sugar protons in both the AP P 9-mer and AP E 9-mer duplexes, including those at the abasic site, have been assigned by recording and analyzing two-dimensional phase-sensitive NOESY data sets in H 2 O and D 2 O solution between -5 and 5 degree C. These spectroscopic observations establish that A5 inserts into the helix opposite the abasic site (P14 and El14) and stacks between the flanking G4·C15 and G6·C13 Watson-Crick base pairs in both the AP P 9-mer and AP E 9-mer duplexes. Proton NMR parameters for the Ap P 9-mer and AP E 9-mer duplexes are similar to those reported previously. These proton NMR experiments demonstrate that the structures at abasic sites are very similar whether the five-membered ring is open or closed or whether the phosphodiester backbone is shortened by one carbon atom. Phosphorus spectra of the AP P 9-mer and AP E 9-mer duplexes (5 degree C) indicate that the backbone conformation is similarly perturbed at three phosphodiester backbone torsion angles

Intramolecular cascade rearrangements of enynamine derived ketenimines: access to acyclic and cyclic amidines.

Science.gov (United States)

Chauhan, Dinesh Pratapsinh; Varma, Sreejith J; Gudem, Mahesh; Panigrahi, Nihar; Singh, Khushboo; Hazra, Anirban; Talukdar, Pinaki

2017-06-07

Copper-catalyzed reaction of enynamines with sulfonylazides provides acyclic and cyclic amidines. Nucleophilic addition of the tethered amino group on the in situ generated ketenimine forms a six-membered cyclic zwitterionic intermediate which facilitates migration of the tethered amino group to the C 5 -center giving the acyclic amidine. On the other hand, migration of a substituent on the amino group to C 2 - and C 4 -centers results in the formation of cyclic amidines. Computational studies were carried out to validate the mechanism which indicates that the product distribution of the process depends on the substitutions on the enynamine backbone.

Towards Optimal Event Detection and Localization in Acyclic Flow Networks

KAUST Repository

Agumbe Suresh, Mahima

2012-01-03

Acyclic flow networks, present in many infrastructures of national importance (e.g., oil & gas and water distribution systems), have been attracting immense research interest. Existing solutions for detecting and locating attacks against these infrastructures, have been proven costly and imprecise, especially when dealing with large scale distribution systems. In this paper, to the best of our knowledge for the first time, we investigate how mobile sensor networks can be used for optimal event detection and localization in acyclic flow networks. Sensor nodes move along the edges of the network and detect events (i.e., attacks) and proximity to beacon nodes with known placement in the network. We formulate the problem of minimizing the cost of monitoring infrastructure (i.e., minimizing the number of sensor and beacon nodes deployed), while ensuring a degree of sensing coverage in a zone of interest and a required accuracy in locating events. We propose algorithms for solving these problems and demonstrate their effectiveness with results obtained from a high fidelity simulator.

Impossibility of an acyclic relativistic electric motor

Energy Technology Data Exchange (ETDEWEB)

Spavieri, G [Universidad de Los Andes, Merida (Venezuela); Cavalleri, G [Milan Univ. (Italy). Ist. di Fisica; Spinelli, G [Padua Univ. (Italy). Ist. di Matematica Applicata

1981-02-11

The relativistic torque acting on a circuit carrying a current and having a uniform translatory motion in a constant and uniform electric field would seem to suggest the possibility of an acyclic relativistic electric motor. However, the net effect on the side parallel to the rotation axis is exactly balanced by the variation of the angular momentum (in the case of an insulating circuit transporting electric charges) or by the external moment due to the magnetic field (in the case of a conducting circuit) acting on the two sides perpendicular to the rotation axis.

On Event Detection and Localization in Acyclic Flow Networks

KAUST Repository

Suresh, Mahima Agumbe

2013-05-01

Acyclic flow networks, present in many infrastructures of national importance (e.g., oil and gas and water distribution systems), have been attracting immense research interest. Existing solutions for detecting and locating attacks against these infrastructures have been proven costly and imprecise, particularly when dealing with large-scale distribution systems. In this article, to the best of our knowledge, for the first time, we investigate how mobile sensor networks can be used for optimal event detection and localization in acyclic flow networks. We propose the idea of using sensors that move along the edges of the network and detect events (i.e., attacks). To localize the events, sensors detect proximity to beacons, which are devices with known placement in the network. We formulate the problem of minimizing the cost of monitoring infrastructure (i.e., minimizing the number of sensors and beacons deployed) in a predetermined zone of interest, while ensuring a degree of coverage by sensors and a required accuracy in locating events using beacons. We propose algorithms for solving the aforementioned problem and demonstrate their effectiveness with results obtained from a realistic flow network simulator.

Metabolism of acyclic and cyclic N-nitroamines by cultured human colon

DEFF Research Database (Denmark)

Autrup, Herman; Harris, Curtis C.; Trump, Benjamin F.

1978-01-01

Cultured human colon mucosa was found to metabolize both acyclic and cyclic N-nitrosamines as measured by 14C-CO2 formation and reaction of the activated moieties with cellular macromolecules. Dimethylnitrosamine and N-nitrosopyrrolidine were metabolized by explants from all patients studied. A p...

Directed Abelian algebras and their application to stochastic models.

Science.gov (United States)

Alcaraz, F C; Rittenberg, V

2008-10-01

With each directed acyclic graph (this includes some D-dimensional lattices) one can associate some Abelian algebras that we call directed Abelian algebras (DAAs). On each site of the graph one attaches a generator of the algebra. These algebras depend on several parameters and are semisimple. Using any DAA, one can define a family of Hamiltonians which give the continuous time evolution of a stochastic process. The calculation of the spectra and ground-state wave functions (stationary state probability distributions) is an easy algebraic exercise. If one considers D-dimensional lattices and chooses Hamiltonians linear in the generators, in finite-size scaling the Hamiltonian spectrum is gapless with a critical dynamic exponent z=D. One possible application of the DAA is to sandpile models. In the paper we present this application, considering one- and two-dimensional lattices. In the one-dimensional case, when the DAA conserves the number of particles, the avalanches belong to the random walker universality class (critical exponent sigma_(tau)=32 ). We study the local density of particles inside large avalanches, showing a depletion of particles at the source of the avalanche and an enrichment at its end. In two dimensions we did extensive Monte-Carlo simulations and found sigma_(tau)=1.780+/-0.005 .

The Reduction of Directed Cyclic Graph for Task Assignment Problem

Directory of Open Access Journals (Sweden)

Ariffin W.N.M.

2018-01-01

Full Text Available In this paper, a directed cyclic graph (DCG is proposed as the task graph. It is undesirable and impossible to complete the task according to the constraints if the cycle exists. Therefore, an effort should be done in order to eliminate the cycle to obtain a directed acyclic graph (DAG, so that the minimum amount of time required for the entire task can be found. The technique of reducing the complexity of the directed cyclic graph to a directed acyclic graph by reversing the orientation of the path is the main contribution of this study. The algorithm was coded using Java programming and consistently produced good assignment and task schedule.

A new recursive incremental algorithm for building minimal acyclic deterministic finite automata

NARCIS (Netherlands)

Watson, B.W.; Martin-Vide, C.; Mitrana, V.

2003-01-01

This chapter presents a new algorithm for incrementally building minimal acyclic deterministic finite automata. Such minimal automata are a compact representation of a finite set of words (e.g. in a spell checker). The incremental aspect of such algorithms (where the intermediate automaton is

Ultrasound-assisted catalytic synthesis of acyclic imides in the presence of p-toluenesulfonic acid under solvent free conditions

Directory of Open Access Journals (Sweden)

Nasr-Esfahani Masoud

2012-01-01

Full Text Available A rapid and convenient preparation of acyclic imides by the reaction of aliphatic and aromatic nitriles with acyclic carboxylic anhydride in the presence of catalytic amounts of p-toluenesulfonic acid under thermal or ultrasonic conditions is reported. The advantages of this procedure are moderate reaction times, good to excellent yields, use of inexpensive and ecofriendly catalyst. The reaction of nitriles with aliphatic anhydrides proceeds in thermal conditions, while by the use of ultrasound irradiations these reactions get accelerated.

Existence principles for inclusions of Hammerstein type involving noncompact acyclic multivalued maps

Directory of Open Access Journals (Sweden)

Jean-Francois Couchouron

2002-01-01

Full Text Available We apply Monch type fixed point theorems for acyclic multivalued maps to the solvability of inclusions of Hammerstein type in Banach spaces. Our approach makes possible to unify and improve the existence theories for nonlinear evolution problems and abstract integral inclusions of Volterra and Fredholm type.

Secretion of antiretroviral chemokines by human cells cultured with acyclic nucleoside phosphonates

Czech Academy of Sciences Publication Activity Database

Zídek, Zdeněk; Kmoníčková, Eva; Holý, Antonín

2007-01-01

Roč. 574, - (2007), s. 77-84 ISSN 0014-2999 R&D Projects: GA MŠk 1M0508 Institutional research plan: CEZ:AV0Z50390512; CEZ:AV0Z40550506 Keywords : Acyclic nucleoside phosphonate * Chemokine * Cytokine Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.376, year: 2007

Highly selective Ba2+ separations with acyclic, lipophilic di-[N-(X)sulfonyl carbamoyl] polyethers.

Science.gov (United States)

Elshani, Sadik; Chun, Sangki; Amiri-Eliasi, Bijan; Bartsch, Richard A

2005-01-14

New lipophilic acyclic polyethers with two N-(X)sulfonyl carbamoyl groups of "tunable" acidity exhibit remarkable selectivity for Ba2+ over other alkaline earth metal ions in competitive solvent extraction and transport across polymer inclusion membranes.

Comparison of construction algorithms for minimal, acyclic, deterministic, finite-state automata from sets of strings

NARCIS (Netherlands)

Daciuk, J; Champarnaud, JM; Maurel, D

2003-01-01

This paper compares various methods for constructing minimal, deterministic, acyclic, finite-state automata (recognizers) from sets of words. Incremental, semi-incremental, and non-incremental methods have been implemented and evaluated.

New prodrugs of two pyrimidine acyclic nucleoside phosphonates: Synthesis and antiviral activity

Czech Academy of Sciences Publication Activity Database

Krečmerová, Marcela; Dračínský, Martin; Snoeck, R.; Balzarini, J.; Pomeisl, Karel; Andrei, G.

2017-01-01

Roč. 25, č. 17 (2017), s. 4637-4648 ISSN 0968-0896 R&D Projects: GA ČR(CZ) GA14-00522S Institutional support: RVO:61388963 Keywords : acyclic nucleoside phosphonates * open-ring * PMEO-DAPy * 5-azacytosine * PME-azaC * HPMP-5-azaC Subject RIV: CC - Organic Chemistry OBOR OECD: Organic chemistry Impact factor: 2.930, year: 2016

Synthesis, structural studies and biological properties of new TBA analogues containing an acyclic nucleotide.

Science.gov (United States)

Coppola, Teresa; Varra, Michela; Oliviero, Giorgia; Galeone, Aldo; D'Isa, Giuliana; Mayol, Luciano; Morelli, Elena; Bucci, Maria-Rosaria; Vellecco, Valentina; Cirino, Giuseppe; Borbone, Nicola

2008-09-01

A new modified acyclic nucleoside, namely N(1)-(3-hydroxy-2-hydroxymethyl-2-methylpropyl)-thymidine, was synthesized and transformed into a building block useful for oligonucleotide (ON) automated synthesis. A series of modified thrombin binding aptamers (TBAs) in which the new acyclic nucleoside replaces, one at the time, the thymidine residues were then synthesized and characterized by UV, CD, MS, and (1)H NMR. The biological activity of the resulting TBAs was tested by Prothrombin Time assay (PT assay) and by purified fibrinogen clotting assay. From a structural point of view, nearly all the new TBA analogues show a similar behavior as the unmodified counterpart, being able to fold into a bimolecular or monomolecular quadruplex structure depending on the nature of monovalent cations (sodium or potassium) coordinated in the quadruplex core. From the comparison of structural and biological data, some important structure-activity relationships emerged, particularly when the modification involved the TT loops. In agreement with previous studies we found that the folding ability of TBA analogues is more affected by modifications involving positions 4 and 13, rather than positions 3 and 12. On the other hand, the highest anti-thrombin activities were detected for aptamers containing the modification at T13 or T12 positions, thus indicating that the effects produced by the introduction of the acyclic nucleoside on the biological activity are not tightly connected with structure stabilities. It is noteworthy that the modification at T7 produces an ON being more stable and active than the natural TBA.

N-Branched acyclic nucleoside phosphonates as monomers for the synthesis of modified oligonucleotides

Czech Academy of Sciences Publication Activity Database

Hocková, Dana; Rosenbergová, Šárka; Ménová, Petra; Páv, Ondřej; Pohl, Radek; Novák, Pavel; Rosenberg, Ivan

2015-01-01

Roč. 13, č. 15 (2015), s. 4449-4458 ISSN 1477-0520 R&D Projects: GA ČR GAP207/11/0108; GA ČR GA13-26526S Institutional support: RVO:61388963 Keywords : acyclic nucleoside phosphonates * oligonucleotides * solid phase synthesis Subject RIV: CC - Organic Chemistry Impact factor: 3.559, year: 2015

Optimal allocation of multi-state retransmitters in acyclic transmission networks

International Nuclear Information System (INIS)

Levitin, Gregory

2002-01-01

In this paper, an algorithm for optimal allocation of multi-state elements (MEs) in acyclic transmission networks (ATNs) is suggested. The ATNs consist of a number of positions (nodes) in which MEs capable of receiving and sending a signal are allocated. Each network has a root position where the signal source is located, a number of leaf positions that can only receive a signal, and a number of intermediate positions containing MEs capable of transmitting the received signal to some other nodes. Each ME that is located in a nonleaf node can have different states determined by a set of nodes receiving the signal directly from this ME. The probability of each state is assumed to be known for each ME. The ATN reliability is defined as the probability that a signal from the root node is transmitted to each leaf node. The optimal distribution of MEs with different characteristics among ATN positions provides the greatest possible ATN reliability. The suggested algorithm is based on using a universal generating function technique for network reliability evaluation. A genetic algorithm is used as the optimization tool. Illustrative examples are presented

Diurnal rhythms in gonadotropins and progesterone in lactating and photoperiod induced acyclic hamsters

International Nuclear Information System (INIS)

Bridges, R.S.; Goldman, B.D.

1975-01-01

Levels of LH, FSH, and progesterone in serum were measured in lactating hamsters and in hamsters in which acyclicity was induced with altered photoperiod. Lactating hamsters were found to have low titers of LH, FSH, and progesterone in serum at 0900 (lights on 0500--1900) on Days 4, 9, 14, and 19 of lactation and increased levels of these hormones at 1600. Levels of LH and FSH in serum at both 0900 and 1600 remained relatively constant throughout lactation. In contrast, levels of progesterone in serum obtained at both 0900 and 1600 sampling times increased as lactation progressed. Ovariectomy on Day 9 of lactation reduced serum levels of progesterone at both 0900 and 1600 and eliminated the afternoon surge in progesterone in animals bled 5 days after surgery. The levels and pattern of LH in serum remained unchanged after ovariectomy in lactating hamsters. However, serum FSH levels in the ovariectomized, lactating animals were elevated at both 0900 and 1600 when compared to levels present in intact, lactating hamsters bled at the same times. Females which were acyclic due to altered photoperiod displayed similar patterns of LH, FSH, and progesterone in serum. Levels of LH, FSH, and progesterone in serum were low at 1000 (lights on 0500--1500) and were increased 2 to 10 fold at 1500. Ovariectomy was followed by lower progesterone levels in serum at 1000 and 1500 and eliminated the afternoon rise of this hormone. Serum levels of LH were unaffected by ovariectomy. As in lactating hamsters, levels of FSH in serum were elevated 3--4 days following ovariectomy at both bleeding times, but the levels were higher at 1500. These results indicate that acyclicity induced by lactation or exposure to a short photoperiod is characterized by similar diurnal patterns of circulating hormones in the hamster

Acyclic ketones in the defensive secretion of a "daddy longlegs" (Leiobunum vittatum).

Science.gov (United States)

Meinwald, J; Kluge, A F; Carrel, J E; Eisner, T

1971-07-01

The defensive secretion of the "daddy longlegs" Leiobunum vittatum was analyzed and found to contain the acyclic ketones 4-methylheptan-3-one and E-4,6-dimethyl-6-octen-3-one as its major organic components. Although 4-methylheptan-3-one has been found previously as an alarm substance in certain ant genera, the second component, whose structure is confirmed by synthesis, is new.

Outstanding effects on antithrombin activity of modified TBA diastereomers containing an optically pure acyclic nucleotide analogue.

Science.gov (United States)

Scuotto, M; Persico, M; Bucci, M; Vellecco, V; Borbone, N; Morelli, E; Oliviero, G; Novellino, E; Piccialli, G; Cirino, G; Varra, M; Fattorusso, C; Mayol, L

2014-07-28

Herein, we report optically pure modified acyclic nucleosides as ideal probes for aptamer modification. These new monomers offer unique advantages in exploring the role played in thrombin inhibition by a single residue modification at key positions of the TBA structure.

Acyclic nucleoside phosphonate antivirals activate gene expression of monocyte chemotactic protein 1 and 3.

Czech Academy of Sciences Publication Activity Database

Potměšil, Petr; Holý, Antonín; Kmoníčková, Eva; Křížková, Jana; Zídek, Zdeněk

2007-01-01

Roč. 14, č. 1 (2007), s. 59-66 ISSN 1021-7770 R&D Projects: GA MŠk 1M0508 Institutional research plan: CEZ:AV0Z50390512; CEZ:AV0Z40550506 Keywords : Acyclic nucleoside phosponate * HIV * Monocyte chemotactic protein Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.024, year: 2007

The preparation of 3-H-labeled Acyclic Nucleoside Phosphonates and Study of their Stability

Czech Academy of Sciences Publication Activity Database

Elbert, Tomáš; Břehová, Petra; Holý, Antonín

2010-01-01

Roč. 75, č. 7 (2010), s. 757-766 ISSN 0010-0765 R&D Projects: GA MŠk 1M0508; GA AV ČR IAA400550801 Institutional research plan: CEZ:AV0Z40550506 Keywords : tritium * 3-H NMR * acyclic nucleotide analogues Subject RIV: CC - Organic Chemistry Impact factor: 0.853, year: 2010

Dimensional crossover in directed percolation

International Nuclear Information System (INIS)

Chame, A.M.N.; Queiroz, S.L.A. de; Santos, Raimundo R. dos.

1984-04-01

We study the dimensional crossover in directed percolation in three dimensions. Bonds are allowed to have different concentrations along the three cartesian axes of the lattice. Through a Position Space Renormalization Group we obtain the phase-diagrama where non-percolating, 1-D, 2-D and 3-D percolating phases are present. We find that the isotropic fixed points are unstable with respect to anisotropy, thus driving the system into a different universality class. (author) [pt

Synthesis, spectroscopic and biological activities studies of acyclic and macrocyclic mono and binuclear metal complexes containing a hard-soft Schiff base.

Science.gov (United States)

Abou-Hussein, Azza A A; Linert, Wolfgang

2012-09-01

Mono- and bi-nuclear acyclic and macrocyclic complexes with hard-soft Schiff base, H(2)L, ligand derived from the reaction of 4,6-diacetylresorcinol and thiocabohydrazide, in the molar ratio 1:2 have been prepared. The H(2)L ligand reacts with Co(II), Ni(II), Cu(II), Zn(II), Mn(II) and UO(2)(VI) nitrates, VO(IV) sulfate and Ru(III) chloride to get acyclic binuclear complexes except for VO(IV) and Ru(III) which gave acyclic mono-nuclear complexes. Reaction of the acyclic mono-nuclear VO(IV) and Ru(III) complexes with 4,6-diacetylresorcinol afforded the corresponding macrocyclic mono-nuclear VO(IV) and Ru(IIII) complexes. Template reactions of the 4,6-diacetylresorcinol and thiocarbohydrazide with either VO(IV) or Ru(III) salts afforded the macrocyclic binuclear VO(IV) and Ru(III) complexes. The Schiff base, H(2)L, ligand acts as dibasic with two NSO-tridentate sites and can coordinate with two metal ions to form binuclear complexes after the deprotonation of the hydrogen atoms of the phenolic groups in all the complexes, except in the case of the acyclic mononuclear Ru(III) and VO(IV) complexes, where the Schiff base behaves as neutral tetradentate chelate with N(2)S(2) donor atoms. The ligands and the metal complexes were characterized by elemental analysis, IR, UV-vis (1)H-NMR, thermal gravimetric analysis (TGA) and ESR, as well as the measurements of conductivity and magnetic moments at room temperature. Electronic spectra and magnetic moments of the complexes indicate the geometries of the metal centers are either tetrahedral, square planar or octahedral. Kinetic and thermodynamic parameters were calculated using Coats-Redfern equation, for the different thermal decomposition steps of the complexes. The ligands and the metal complexes were screened for their antimicrobial activity against Staphylococcus aureus as Gram-positive bacteria, and Pseudomonas fluorescens as Gram-negative bacteria in addition to Fusarium oxysporum fungus. Most of the complexes exhibit

Design and Synthesis of Fluorescent Acyclic Nucleoside Phosphonates as Potent Inhibitors of Bacterial Adenylate Cyclases

Czech Academy of Sciences Publication Activity Database

Břehová, Petra; Šmídková, Markéta; Skácel, Jan; Dračínský, Martin; Mertlíková-Kaiserová, Helena; Velasquez, M. P. S.; Watts, V. J.; Janeba, Zlatko

2016-01-01

Roč. 11, č. 22 (2016), s. 2534-2546 ISSN 1860-7179 R&D Projects: GA MV VG20102015046; GA MŠk LO1302 Institutional support: RVO:61388963 Keywords : adenylate cyclase toxin * acyclic nucleoside phosphonates * anthranilic acid Subject RIV: CC - Organic Chemistry Impact factor: 3.225, year: 2016

Acyclic Ketones in the Defensive Secretion of a “Daddy Longlegs” (Leiobunum vittatum)

Science.gov (United States)

Meinwald, J.; Kluge, A. F.; Carrel, J. E.; Eisner, T.

1971-01-01

The defensive secretion of the “daddy longlegs” Leiobunum vittatum was analyzed and found to contain the acyclic ketones 4-methylheptan-3-one and E-4,6-dimethyl-6-octen-3-one as its major organic components. Although 4-methylheptan-3-one has been found previously as an alarm substance in certain ant genera, the second component, whose structure is confirmed by synthesis, is new. PMID:5283937

Investigating temporary acyclicity in a captive group of Asian elephants (Elephas maximus): Relationship between management, adrenal activity and social factors.

Science.gov (United States)

Edwards, Katie L; Trotter, Jessica; Jones, Martin; Brown, Janine L; Steinmetz, Hanspeter W; Walker, Susan L

2016-01-01

Routine faecal steroid monitoring has been used to aid the management of five captive Asian elephant (Elephas maximus) females at Chester Zoo, UK, since 2007. Progestagen analysis initially revealed synchronised oestrous cycles among all females. However, a 14- to 20-week period of temporary acyclicity subsequently occurred in three females, following several management changes (increased training, foot-care and intermittent matriarch removal for health reasons) and the initiation of pregnancy in another female. The aim of this study was to retrospectively investigate whether these management changes were related to increased adrenal activity and disruption of ovarian activity, or whether social factors may have been involved in the temporary cessation of cyclicity. Faecal samples collected every other day were analysed to investigate whether glucocorticoid metabolites were related to reproductive status (pregnant, cycling, acyclic) or management (training, foot-care, matriarch presence). Routine training and foot-care were not associated with adrenal activity; however, intensive foot-care to treat an abscess in one female was associated with increased glucocorticoid concentration. Matriarch presence influenced adrenal activity in three females, being lower when the matriarch was separated from the group at night compared to being always present. However, in the females that exhibited temporary acyclicity, there was no consistent relationship between glucocorticoids and cyclicity state. Although the results of this study do not fully explain this occurrence, the highly synchronised nature of oestrous cycles within this group, and the concurrent acyclicity in three females, raises the question of whether social factors could have been involved in the temporary disruption of ovarian activity. Copyright © 2015 Elsevier Inc. All rights reserved.

The efficient synthesis of 2-arylpyrimidine acyclic nucleoside phosphonates using Liebeskind-Srogl cross-coupling reaction

Czech Academy of Sciences Publication Activity Database

Břehová, Petra; Česnek, Michal; Dračínský, Martin; Holý, Antonín; Janeba, Zlatko

2011-01-01

Roč. 67, č. 38 (2011), s. 7379-7385 ISSN 0040-4020 R&D Projects: GA MŠk 1M0508 Institutional research plan: CEZ:AV0Z40550506 Keywords : Liebeskind-Srogl cross - coupling * acyclic nucleoside phosphonates * pyrimidines * arylboronic acids * microwave Subject RIV: CC - Organic Chemistry Impact factor: 3.025, year: 2011

Spectral, Electrochemical, Fluorescence, Kinetic and Anti-microbial Studies of Acyclic Schiff-base Gadolinium(III) Complexes

International Nuclear Information System (INIS)

Vijayaraj, A.; Prabu, R.; Suresh, R.; Narayanan, V.; Sangeetha Kumari, R.; Kaviyarasan, V.

2012-01-01

A new series of acyclic mononuclear gadolinium(III) complexes have been prepared by Schiff-base condensation derived from 5-methylsalicylaldehyde, diethylenetriamine, tris(2-aminoethyl) amine, triethylenetetramine, N,N-bis(3-aminopropyl)ethylene diamine, N,N-bis(aminopropyl) piperazine, and gadolinium nitrate. All the complexes were characterized by elemental and spectral analyses. Electronic spectra of the complexes show azomethine (CH=N) within the range of 410-420 nm. The fluorescence efficiency of Gd(III) ion in the cavity was completely quenched by the higher chain length ligands. Electrochemical studies of the complexes show irreversible one electron reduction process around -2.15 to -1.60 V. The reduction potential of gadolinium(III) complexes shifts towards anodic directions respectively upon increasing the chain length. The catalytic activity of the gadolinium(III) complexes on the hydrolysis of 4-nitrophenylphosphate was determined. All gadolinium(III) complexes were screened for antibacterial activity

Spectral, Electrochemical, Fluorescence, Kinetic and Anti-microbial Studies of Acyclic Schiff-base Gadolinium(III) Complexes

Energy Technology Data Exchange (ETDEWEB)

Vijayaraj, A.; Prabu, R.; Suresh, R.; Narayanan, V.; Sangeetha Kumari, R.; Kaviyarasan, V. [Univ. of Madras, Madras (India)

2012-11-15

A new series of acyclic mononuclear gadolinium(III) complexes have been prepared by Schiff-base condensation derived from 5-methylsalicylaldehyde, diethylenetriamine, tris(2-aminoethyl) amine, triethylenetetramine, N,N-bis(3-aminopropyl)ethylene diamine, N,N-bis(aminopropyl) piperazine, and gadolinium nitrate. All the complexes were characterized by elemental and spectral analyses. Electronic spectra of the complexes show azomethine (CH=N) within the range of 410-420 nm. The fluorescence efficiency of Gd(III) ion in the cavity was completely quenched by the higher chain length ligands. Electrochemical studies of the complexes show irreversible one electron reduction process around -2.15 to -1.60 V. The reduction potential of gadolinium(III) complexes shifts towards anodic directions respectively upon increasing the chain length. The catalytic activity of the gadolinium(III) complexes on the hydrolysis of 4-nitrophenylphosphate was determined. All gadolinium(III) complexes were screened for antibacterial activity.

Synthesis of alpha-Branched Acyclic Nucleoside Phosphonates as Potential Inhibitors of Bacterial Adenylate Cyclases

Czech Academy of Sciences Publication Activity Database

Frydrych, Jan; Skácel, Jan; Šmídková, Markéta; Mertlíková-Kaiserová, Helena; Dračínský, Martin; Gnanasekaran, Ramachandran; Lepšík, Martin; Soto-Velasquez, M.; Watts, V. J.; Janeba, Zlatko

2018-01-01

Roč. 13, č. 2 (2018), s. 199-206 ISSN 1860-7179 R&D Projects: GA MV VG20102015046; GA ČR(CZ) GBP208/12/G016; GA MŠk LO1302 Institutional support: RVO:61388963 Keywords : acyclic nucleoside phosphonates * adenylate cyclase toxin * bisamidates * Bordetella pertussis * prodrugs Subject RIV: CC - Organic Chemistry OBOR OECD: Organic chemistry Impact factor: 3.225, year: 2016

Birkhoff-Kellogg theorems on invariant directions for multimaps

Directory of Open Access Journals (Sweden)

Donal O'Regan

2003-04-01

Full Text Available We establish Birkhoff-Kellogg type theorems on invariant directions for a general class of maps. Our results, in particular, apply to Kakutani, acyclic, O'Neill, approximable, admissible, and 𝒰cκ maps.

Direct Linear Transformation Method for Three-Dimensional Cinematography

Science.gov (United States)

Shapiro, Robert

1978-01-01

The ability of Direct Linear Transformation Method for three-dimensional cinematography to locate points in space was shown to meet the accuracy requirements associated with research on human movement. (JD)

Directional detection of dark matter with two-dimensional targets

Science.gov (United States)

Hochberg, Yonit; Kahn, Yonatan; Lisanti, Mariangela; Tully, Christopher G.; Zurek, Kathryn M.

2017-09-01

We propose two-dimensional materials as targets for direct detection of dark matter. Using graphene as an example, we focus on the case where dark matter scattering deposits sufficient energy on a valence-band electron to eject it from the target. We show that the sensitivity of graphene to dark matter of MeV to GeV mass can be comparable, for similar exposure and background levels, to that of semiconductor targets such as silicon and germanium. Moreover, a two-dimensional target is an excellent directional detector, as the ejected electron retains information about the angular dependence of the incident dark matter particle. This proposal can be implemented by the PTOLEMY experiment, presenting for the first time an opportunity for directional detection of sub-GeV dark matter.

Inhibition of hypoxanthine-guanine phosphoribosyltransferase by acyclic nucleoside phosphonates: A new class of antimalarial therapeutics

Czech Academy of Sciences Publication Activity Database

Keough, D. T.; Hocková, Dana; Holý, Antonín; Naesens, L.; Skinner-Adams, T. S.; de Jersey, J.; Guddat, L. W.

2009-01-01

Roč. 52, č. 14 (2009), s. 4391-4399 ISSN 0022-2623 R&D Projects: GA MŠk 1M0508; GA AV ČR 1QS400550501 Institutional research plan: CEZ:AV0Z40550506 Keywords : acyclic nucleoside phosphonates * phosphoribosyltransferase * enzyme inhibitors * Plasmodium falciparum Subject RIV: CC - Organic Chemistry Impact factor: 4.802, year: 2009

Enhanced Topical and Transdermal Delivery of Antineoplastic and Antiviral Acyclic Nucleoside Phosphonate cPr-PMEDAP

Czech Academy of Sciences Publication Activity Database

Vávrová, K.; Kovaříková, P.; Školová, B.; Líbalová, M.; Roh, J.; Čáp, R.; Holý, Antonín; Hrabálek, A.

2011-01-01

Roč. 28, č. 12 (2011), s. 3105-3115 ISSN 0724-8741 R&D Projects: GA MŠk 1M0508 Grant - others:GA ČR(CZ) GAP207/11/0365 Institutional research plan: CEZ:AV0Z40550506 Keywords : acyclic nucleoside phosphonates * antivirals * antineoplastics * permeation enhancer * topical skin application * transdermal delivery Subject RIV: CC - Organic Chemistry Impact factor: 4.093, year: 2011

Structure-Activity Relationships of Acyclic Selenopurine Nucleosides as Antiviral Agents

Directory of Open Access Journals (Sweden)

Pramod K. Sahu

2017-07-01

Full Text Available A series of acyclic selenopurine nucleosides 3a–f and 4a–g were synthesized based on the bioisosteric rationale between oxygen and selenium, and then evaluated for antiviral activity. Among the compounds tested, seleno-acyclovir (4a exhibited the most potent anti-herpes simplex virus (HSV-1 (EC50 = 1.47 µM and HSV-2 (EC50 = 6.34 µM activities without cytotoxicity up to 100 µM, while 2,6-diaminopurine derivatives 4e–g exhibited significant anti-human cytomegalovirus (HCMV activity, which is slightly more potent than the guanine derivative 4d, indicating that they might act as prodrugs of seleno-ganciclovir (4d.

Reaction of acyclic enaminones with methoxymethylene meldrum's acid: synthetic and structural implications

OpenAIRE

Cunha,Silvio; Silva,Viviane C. da; Napolitano,Hamilton B.; Lariucci,Carlito; Vencato,Ivo

2003-01-01

The reaction of acyclic enaminones with methoxymethylene Meldrum's acid afforded N-adduct and/or C-adduct of enaminones in moderate to good yields. The regiochemistry of this reaction depends on the N-amino substituent of the enaminone. The C-adduct is a precursor to 2-pyridones. X-ray analysis of two N-adducts were investigated and the Z-s-Z configuration assigned. A reação de enaminonas com o derivado metoximetilênico do ácido de Meldrum forneceu N-adutos e/ou C-adutos das enaminonas, em...

Interaction of phosphates of the acyclic nucleoside phosphonates with nucleoside diphosphate kinase from yeast and bovine liver

Czech Academy of Sciences Publication Activity Database

Horská, Květoslava; Votruba, Ivan; Holý, Antonín

2006-01-01

Roč. 71, č. 1 (2006), s. 35-43 ISSN 0010-0765 R&D Projects: GA AV ČR(CZ) IBS4055109 Institutional research plan: CEZ:AV0Z40550506 Keywords : enzymatic phosphorylation * acyclic nucleotide analogs * NTP analogues Subject RIV: CC - Organic Chemistry Impact factor: 0.881, year: 2006

Acyclic nucleoside bisphosphonates: Synthesis and properties of chiral 2-amino-4,6-bis[(phosphonomethoxy)alkoxy]pyrimidines

Czech Academy of Sciences Publication Activity Database

Doláková, Petra; Dračínský, Martin; Masojídková, Milena; Šolínová, Veronika; Kašička, Václav; Holý, Antonín

2009-01-01

Roč. 44, č. 6 (2009), s. 2408-2424 ISSN 0223-5234 R&D Projects: GA MŠk 1M0508 Grant - others:NIH(US) 1UC1AIO62540-01 Institutional research plan: CEZ:AV0Z40550506 Keywords : acyclic nucleoside phosphonates * pyrimidine * bisphosphonates Subject RIV: CC - Organic Chemistry Impact factor: 3.269, year: 2009

Acid-Labile Acyclic Cucurbit[n]uril Molecular Containers for Controlled Release.

Science.gov (United States)

Mao, Dake; Liang, Yajun; Liu, Yamin; Zhou, Xianhao; Ma, Jiaqi; Jiang, Biao; Liu, Jia; Ma, Da

2017-10-02

Stimuli-responsive molecular containers are of great importance for controlled drug delivery and other biomedical applications. A new type of acid labile acyclic cucurbit[n]uril (CB[n]) molecular containers is presented that can degrade and release the encapsulated cargo at accelerated rates under mildly acidic conditions (pH 5.5-6.5). These containers retain the excellent recognition properties of CB[n]-type hosts. A cell culture study demonstrated that the cellular uptake of cargos could be fine-tuned by complexation with different containers. The release and cell uptake of cargo dye was promoted by acidic pH. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Direct unavailability computation of a maintained highly reliable system

Czech Academy of Sciences Publication Activity Database

Briš, R.; Byczanski, Petr

2010-01-01

Roč. 224, č. 3 (2010), s. 159-170 ISSN 1748-0078 Grant - others:GA Mšk(CZ) MSM6198910007 Institutional research plan: CEZ:AV0Z30860518 Keywords : high reliability * availability * directed acyclic graph Subject RIV: BA - General Mathematics http:// journals .pepublishing.com/content/rtp3178l17923m46/

Comparative reactivity of different types of stable cyclic and acyclic mono- and diamino carbenes with simple organic substrates.

Science.gov (United States)

Martin, David; Canac, Yves; Lavallo, Vincent; Bertrand, Guy

2014-04-02

A series of stable carbenes, featuring a broad range of electronic properties, were reacted with simple organic substrates. The N,N-dimesityl imidazolylidene (NHC) does not react with isocyanides, whereas anti-Bredt di(amino)carbene (pyr-NHC), cyclic (alkyl)(amino)carbene (CAAC), acyclic di(amino)carbene (ADAC), and acyclic (alkyl)(amino)carbene (AAAC) give rise to the corresponding ketenimines. NHCs are known to promote the benzoin condensation, and we found that the CAAC, pyr-NHC, and ADAC react with benzaldehyde to give the ketone tautomer of the Breslow intermediate, whereas the AAAC first gives the corresponding epoxide and ultimately the Breslow intermediate, which can be isolated. Addition of excess benzaldehyde to the latter does not lead to benzoin but to a stable 1,3-dioxolane. Depending on the electronic properties of carbenes, different products are also obtained with methyl acrylate as a substrate. The critical role of the carbene electrophilicity on the outcome of reactions is discussed.

Characterization of E and Z isomers in macrocyclic lactones and acyclic pheromones by NMR spectra

International Nuclear Information System (INIS)

Mahajan, J.R.; Resck, I.S.; Braz Filho, R.; Carvalho, M.G. de

1995-01-01

A large proportion of pheromones, isolated from a variety of insects, constitutes a big list of diversely functionalized acyclic compounds, which have been synthesized by several routes. Catalytic or chemical methods were examined for the Z to E isomerization and their efficiency checked by 1 H and 13 C NMR spectra. Nuclear magnetic resonance has been used to identify and characterize molecular structure of the compounds, besides chemical shifts was analysed

Synthesis and Evaluation of Novel Acyclic Nucleoside Phosphonates as Inhibitors of Plasmodium falciparum and Human 6-Oxopurine Phosphoribosyltransferases

Czech Academy of Sciences Publication Activity Database

Kaiser, Martin Maxmilian; Hocková, Dana; Wang, T. H.; Dračínský, Martin; Poštová Slavětínská, Lenka; Procházková, Eliška; Edstein, M. D.; Chavchich, M.; Keough, D. T.; Guddat, L. W.; Janeba, Zlatko

2015-01-01

Roč. 10, č. 10 (2015), s. 1707-1723 ISSN 1860-7179 R&D Projects: GA MV VG20102015046; GA ČR GAP207/11/0108 Institutional support: RVO:61388963 Keywords : 6-oxopurine * acyclic nucleoside phosphonates * phosphoribosyltransferases * malaria * phosphoramidates Subject RIV: CC - Organic Chemistry Impact factor: 2.980, year: 2015

Enantiopurity analysis of new types of acyclic nucleoside phosphonates by capillary electrophoresis with cyclodextrins as chiral selectors

Czech Academy of Sciences Publication Activity Database

Šolínová, Veronika; Kaiser, Martin Maxmilian; Lukáč, Miloš; Janeba, Zlatko; Kašička, Václav

2014-01-01

Roč. 37, č. 3 (2014), s. 295-303 ISSN 1615-9306 R&D Projects: GA ČR(CZ) GAP206/12/0453; GA ČR(CZ) GA13-17224S; GA MV VG20102015046 Institutional support: RVO:61388963 Keywords : acyclic nucleoside phosphonates * CE * chiral analysis * cyclodextrins * nucleotide analogs Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.737, year: 2014

Influence of Acyclic Nucleoside Phosphonate Antivirals on Gene Expression of Chemokine Receptors CCR5 and CXCR4

Czech Academy of Sciences Publication Activity Database

Potměšil, P.; Holý, Antonín; Zídek, Zdeněk

2015-01-01

Roč. 61, č. 1 (2015), s. 1-7 ISSN 0015-5500 R&D Projects: GA ČR GA305/03/1470; GA MŠk 1M0508 Institutional support: RVO:61388963 ; RVO:68378041 Keywords : acyclic nucleoside phosphonate * HIV * CCR5 * CXCR4 * cytokine * RT-PCR Subject RIV: CC - Organic Chemistry; FR - Pharmacology ; Medidal Chemistry (UEM-P) Impact factor: 0.833, year: 2015

Sequential Optimization of Paths in Directed Graphs Relative to Different Cost Functions

KAUST Repository

Abubeker, Jewahir Ali

2011-05-14

This paper is devoted to the consideration of an algorithm for sequential optimization of paths in directed graphs relative to di_erent cost functions. The considered algorithm is based on an extension of dynamic programming which allows to represent the initial set of paths and the set of optimal paths after each application of optimization procedure in the form of a directed acyclic graph.

Rhodium-Catalyzed Insertion Reaction of PhP Group of Pentaphenylcyclopentaphosphine with Acyclic and Cyclic Disulfides.

Science.gov (United States)

Arisawa, Mieko; Sawahata, Kyosuke; Yamada, Tomoki; Sarkar, Debayan; Yamaguchi, Masahiko

2018-02-16

Organophosphorus compounds with a phosphorus atom attached to a phenyl group and two organothio/organoseleno groups were synthesized using the rhodium-catalyzed insertion reaction of the PhP group of pentaphenylcyclopentaphosphine (PhP) 5 with acyclic disulfides and diselenides. The method was applied to the synthesis of heterocyclic compounds containing the S-P-S group by the reaction of (PhP) 5 and cyclic disulfides such as 1,2-dithietes, 1,2-dithiocane, 1,4,5-dithiopane, and 1,2-dithiolanes.

Synthesis and biological evaluation of acyclic nucleotide analogues with a furo[2,3-d]pyrimidin-2(3H)-one base

Czech Academy of Sciences Publication Activity Database

Janeba, Zlatko; Holý, Antonín; Pohl, Radek; Snoeck, R.; Andrei, G.; De Clercq, E.; Balzarini, J.

2010-01-01

Roč. 88, č. 7 (2010), s. 628-638 ISSN 0008-4042 R&D Projects: GA MŠk 1M0508 Institutional research plan: CEZ:AV0Z40550506 Keywords : acyclic nucleoside phosphonates * Sonogashira reaction * intramolecular cyclization Subject RIV: CC - Organic Chemistry Impact factor: 1.374, year: 2010

Competitive solvent extraction of alkaline-earth cations into chloroform by lipophilic acyclic polyether dicarboxylic acids

International Nuclear Information System (INIS)

Kang, S.I.; Czech, A.; Czech, B.P.; Stewart, L.E.; Bartsch, R.A.

1985-01-01

Competitive solvent extraction of alkaline-earth cations from aqueous solutions into chloroform by a series of lipophilic acyclic polyether dicarboxylic acids is reported. The influence of polyether chain length and of terminal carboxylic acid group variation upon extraction selectivity and efficiency is assessed. In the competitive extraction of concentrated magnesium, calcium, strontium and barium chloride solutions, one complexing agent exhibits pronounced selectivity for barium with Ba 2+ /S 2+ = 50, Ba 2+ /Ca 2+ = 250, and no detectable Mg 2+ extraction. 20 references, 3 figures, 1 table

Influence of Two Acyclic Homoterpenes (Tetranorterpenes) on the Foraging Behavior of Anthonomus grandis Boh.

Science.gov (United States)

Magalhães, D M; Borges, M; Laumann, R A; Woodcock, C M; Pickett, J A; Birkett, M A; Blassioli-Moraes, Maria Carolina

2016-04-01

Previous studies have shown that the boll weevil, Anthonomus grandis, is attracted to constitutive and conspecific herbivore-induced cotton volatiles, preferring the blend emitted by cotton at the reproductive over the vegetative stage. Moreover, this preference was paralleled by the release of the acyclic homoterpenes (tetranorterpenes) (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT) and (E,E)-4,8,12-trimethyltrideca-1,3,7,11-tetraene (TMTT) in Delta Opal cotton being higher at the vegetative than at the reproductive stage. Here, we evaluated whether this difference in release of acyclic homoterpenes also occurred in other cotton varieties, and if boll weevils could recognize these compounds as indicators of a specific cotton phenological stage. Results showed that cotton genotypes CNPA TB-90, BRS-293 and Delta Opal all produced higher levels of DMNT and TMTT at the vegetative stage than at the reproductive stage and that these homoterpenes allowed for principal component analysis separation of volatiles produced by the two phenological stages. Electroantennograms confirmed boll weevil antennal responses to DMNT and TMTT. Behavioral assays, using Y-tube olfactometers, showed that adding synthetic homoterpenes to reproductive cotton volatiles (mimicking cotton at the vegetative stage in terms of homoterpene levels) resulted in reduced attraction to boll weevils compared to that to unmodified reproductive cotton. Weevils showed no preference when given a choice between plants at the vegetative stage and the vegetative stage-mimicked plant. Altogether, the results show that DMNT and TMTT are used by boll weevils to distinguish between cotton phenological stages.

Maximizing survivability of acyclic transmission networks with multi-state retransmitters and vulnerable nodes

International Nuclear Information System (INIS)

Levitin, Gregory

2002-01-01

In this paper, an algorithm for optimal allocation of multi-state elements (MEs) in acyclic transmission networks (ATNs) with vulnerable nodes is suggested. The ATNs consist of a number of positions (nodes) in which MEs capable of receiving and sending a signal are allocated. Each network has a root position where the signal source is located, a number of leaf positions that can only receive a signal, and a number of intermediate positions containing MEs capable of transmitting the received signal to some other nodes. Each ME that is located in a nonleaf node can have different states determined by a set of nodes receiving the signal directly from this ME. The probability of each state is assumed to be known for each ME. Each ATN node with all the MEs allocated at this node can be destroyed by external impact (common cause failure) with a given probability. The ATN survivability is defined as the probability that a signal from the root node is transmitted to each leaf node. The optimal distribution of MEs with different characteristics among ATN positions provides the greatest possible ATN survivability. It is shown that the node vulnerability index affects the optimal distribution. The suggested algorithm is based on using a universal generating function technique for network survivability evaluation. A genetic algorithm is used as the optimization tool. Illustrative examples are presented

Estimation of apparent binding constant of complexes of selected acyclic nucleoside phosphonates with beta-cyclodextrin by affinity capillary electrophoresis

Czech Academy of Sciences Publication Activity Database

Šolínová, Veronika; Mikysková, Hana; Kaiser, Martin Maxmilian; Janeba, Zlatko; Holý, Antonín; Kašička, Václav

2016-01-01

Roč. 37, č. 2 (2016), s. 239-247 ISSN 0173-0835 R&D Projects: GA ČR(CZ) GA13-17224S; GA ČR(CZ) GA15-01948S Institutional support: RVO:61388963 Keywords : acyclic nucleoside phosphonates * affinity capillary electrophoresis * binding constant * nucleotide analogs * beta-cyclodextrin Subject RIV: CB - Analytical Chemistry , Separation Impact factor: 2.744, year: 2016

New acyclic secondary metabolites from the biologically active fraction of Albizia lebbeck flowers.

Science.gov (United States)

Al-Massarani, Shaza M; El Gamal, Ali A; Abd El Halim, Mohamed F; Al-Said, Mansour S; Abdel-Kader, Maged S; Basudan, Omer A; Alqasoumi, Saleh I

2017-01-01

The total extract of Albizia lebbeck flowers was examined in vivo for its possible hepatoprotective activity in comparison with the standard drug silymarin at two doses. The higher dose expressed promising activity especially in reducing the levels of AST, ALT and bilirubin. Fractionation via liquid-liquid partition and reexamination of the fractions revealed that the n -butanol fraction was the best in improving liver biochemical parameters followed by the n -hexane fraction. However, serum lipid parameters were best improved with CHCl 3 fraction. The promising biological activity results initiated an intensive chromatographic purification of A. lebbeck flowers fractions. Two compounds were identified from natural source for the first time, the acyclic farnesyl sesquiterpene glycoside1-O-[6-O- α -l-arabinopyranosyl- β -d-glucopyranoside]-(2 E ,6 E -)-farnesol ( 6 ) and the squalene derivative 2,3-dihydroxy-2,3-dihydrosqualene ( 9 ), in addition to eight compounds reported here for the first time from the genus Albizia ; two benzyl glycosides, benzyl 1-O- β -d-glucopyranoside ( 1 ) and benzyl 6-O- α -l-arabinopyranosyl β -d-glucopyranoside ( 2 ); three acyclic monoterpene glycosides, linalyl β -d-glucopyranoside ( 3 ) and linalyl 6-O- α -l-arabinopyranosyl- β -d-glucopyranoside ( 4 ); (2 E )-3,7-dimethylocta-2,6-dienoate-6-O- α -l arabinopyranosyl- β -d-glucopyranoside ( 5 ), two oligoglycosides, n -hexyl- α -l arabinopyranosyl-(1 → 6)- β -d-glucopyranoside (creoside) ( 7 ) and n -octyl α -l-arabinopyranosyl-(1 → 6)- β -d-glucopyranoside (rhodiooctanoside) ( 8 ); and ethyl fructofuranoside ( 10 ). The structures of the isolated compounds were elucidated based on extensive examination of their spectroscopic 1D and 2D-NMR, MS, UV, and IR data. It is worth mentioning that, some of the isolated linalol glycoside derivatives were reported as aroma precursors.

New acyclic secondary metabolites from the biologically active fraction of Albizia lebbeck flowers

Directory of Open Access Journals (Sweden)

Shaza M. Al-Massarani

2017-01-01

Full Text Available The total extract of Albizia lebbeck flowers was examined in vivo for its possible hepatoprotective activity in comparison with the standard drug silymarin at two doses. The higher dose expressed promising activity especially in reducing the levels of AST, ALT and bilirubin. Fractionation via liquid–liquid partition and reexamination of the fractions revealed that the n-butanol fraction was the best in improving liver biochemical parameters followed by the n-hexane fraction. However, serum lipid parameters were best improved with CHCl3 fraction. The promising biological activity results initiated an intensive chromatographic purification of A. lebbeck flowers fractions. Two compounds were identified from natural source for the first time, the acyclic farnesyl sesquiterpene glycoside1-O-[6-O-α-l-arabinopyranosyl-β-d-glucopyranoside]-(2E,6E--farnesol (6 and the squalene derivative 2,3-dihydroxy-2,3-dihydrosqualene (9, in addition to eight compounds reported here for the first time from the genus Albizia; two benzyl glycosides, benzyl 1-O-β-d-glucopyranoside (1 and benzyl 6-O-α-l-arabinopyranosyl β-d-glucopyranoside (2; three acyclic monoterpene glycosides, linalyl β-d-glucopyranoside (3 and linalyl 6-O-α-l-arabinopyranosyl-β-d-glucopyranoside (4; (2E-3,7-dimethylocta-2,6-dienoate-6-O-α-l arabinopyranosyl-β-d-glucopyranoside (5, two oligoglycosides, n-hexyl-α-l arabinopyranosyl-(1 → 6-β-d-glucopyranoside (creoside (7 and n-octyl α-l-arabinopyranosyl-(1 → 6-β-d-glucopyranoside (rhodiooctanoside (8; and ethyl fructofuranoside (10. The structures of the isolated compounds were elucidated based on extensive examination of their spectroscopic 1D and 2D-NMR, MS, UV, and IR data. It is worth mentioning that, some of the isolated linalol glycoside derivatives were reported as aroma precursors.

Acyclic cucurbit[n]uril-type molecular containers: influence of aromatic walls on their function as solubilizing excipients for insoluble drugs.

Science.gov (United States)

Zhang, Ben; Isaacs, Lyle

2014-11-26

We studied the influence of the aromatic sidewalls on the ability of acyclic CB[n]-type molecular containers (1a-1e) to act as solubilizing agents for 19 insoluble drugs including the developmental anticancer agent PBS-1086. All five containers exhibit good water solubility and weak self-association (Ks ≤ 624 M(-1)). We constructed phase solubility diagrams to extract Krel and Ka values for the container·drug complexes. The acyclic CB[n]-type containers generally display significantly higher Ka values than HP-β-CD toward drugs. Containers 1a-1e bind the steroidal ring system and aromatic moieties of insoluble drugs. Compound 1b displays highest affinity toward most of the drugs studied. Containers 1a and 1b are broadly applicable and can be used to formulate a wider variety of insoluble drugs than was previously possible with cyclodextrin technology. For drugs that are solubilized by both HP-β-CD and 1a-1e, lower concentrations of 1a-1e are required to achieve identical [drug].

Binding Direction-Based Two-Dimensional Flattened Contact Area Computing Algorithm for Protein-Protein Interactions.

Science.gov (United States)

Kang, Beom Sik; Pugalendhi, GaneshKumar; Kim, Ku-Jin

2017-10-13

Interactions between protein molecules are essential for the assembly, function, and regulation of proteins. The contact region between two protein molecules in a protein complex is usually complementary in shape for both molecules and the area of the contact region can be used to estimate the binding strength between two molecules. Although the area is a value calculated from the three-dimensional surface, it cannot represent the three-dimensional shape of the surface. Therefore, we propose an original concept of two-dimensional contact area which provides further information such as the ruggedness of the contact region. We present a novel algorithm for calculating the binding direction between two molecules in a protein complex, and then suggest a method to compute the two-dimensional flattened area of the contact region between two molecules based on the binding direction.

Binding Direction-Based Two-Dimensional Flattened Contact Area Computing Algorithm for Protein–Protein Interactions

Directory of Open Access Journals (Sweden)

Beom Sik Kang

2017-10-01

Full Text Available Interactions between protein molecules are essential for the assembly, function, and regulation of proteins. The contact region between two protein molecules in a protein complex is usually complementary in shape for both molecules and the area of the contact region can be used to estimate the binding strength between two molecules. Although the area is a value calculated from the three-dimensional surface, it cannot represent the three-dimensional shape of the surface. Therefore, we propose an original concept of two-dimensional contact area which provides further information such as the ruggedness of the contact region. We present a novel algorithm for calculating the binding direction between two molecules in a protein complex, and then suggest a method to compute the two-dimensional flattened area of the contact region between two molecules based on the binding direction.

One- and Two-dimensional Solitary Wave States in the Nonlinear Kramers Equation with Movement Direction as a Variable

Science.gov (United States)

Sakaguchi, Hidetsugu; Ishibashi, Kazuya

2018-06-01

We study self-propelled particles by direct numerical simulation of the nonlinear Kramers equation for self-propelled particles. In our previous paper, we studied self-propelled particles with velocity variables in one dimension. In this paper, we consider another model in which each particle exhibits directional motion. The movement direction is expressed with a variable ϕ. We show that one-dimensional solitary wave states appear in direct numerical simulations of the nonlinear Kramers equation in one- and two-dimensional systems, which is a generalization of our previous result. Furthermore, we find two-dimensionally localized states in the case that each self-propelled particle exhibits rotational motion. The center of mass of the two-dimensionally localized state exhibits circular motion, which implies collective rotating motion. Finally, we consider a simple one-dimensional model equation to qualitatively understand the formation of the solitary wave state.

Direct-coupled-ray method for design-oriented three-dimensional transport analysis

International Nuclear Information System (INIS)

Bucholz, J.A.; Poncelet, C.G.

1977-01-01

A fast three-dimensional design-oriented transport method has been developed for the solution of both neutron and gamma transport problems. It combines a nodal approach with analytic integral transport to achieve relative speed and accuracy. An analytic solution is obtained for the angular flux in each of the 14 directions defined by the six faces and eight corners of a cubic mesh block. The scheme used to accommodate high-order anisotropic scattering is based on the formulation of ray-to-ray scattering probabilities in an integral sense. A variable mesh approximation has also been introduced to provide greater flexibility. The details of a direct-coupled-ray (DCR) → P 1 conversion technique have been developed but not yet implemented. The DCR method, as implemented in the TRANS3 code, has been used in a number of liquid-metal fast breeder reactor shielding applications. These included a one-dimensional deep penetration configuration and one-, two-, and three dimensional representations of the lower axial shield of the Clinch River Breeder Reactor. Comparisons with ANISN and DOT-III solutions indicated good to excellent agreement in most situations

Acyclic N-halamine-immobilized polyurethane: Preparation and antimicrobial and biofilm-controlling functions

Science.gov (United States)

Luo, Jie; Porteous, Nuala; Lin, Jiajin; Sun, Yuyu

2015-01-01

Hydroxyl groups were introduced onto polyurethane surfaces through 1,6-hexamethylene diisocyanate activation, followed by diethanolamine hydroxylation. Polymethacrylamide was covalently attached to the hydroxylated polyurethane through surface grafting polymerization of methacrylamide using cerium (IV) ammonium nitrate as an initiator. After bleach treatment, the amide groups of the covalently bound polymethacrylamide chains were transformed into N-halamines. The new N-halamine-immobilized polyurethane provided a total sacrifice of 107–108 colony forming units per milliliter of Staphylococcus aureus (Gram-positive bacteria), Escherichia coli (Gram-negative bacteria), and Candida albicans (fungi) within 10 min and successfully prevented bacterial and fungal biofilm formation. The antimicrobial and biofilm-controlling effects were both durable and rechargeable, pointing to great potentials of the new acyclic N-halamine-immobilized polyurethane for a broad range of related applications. PMID:26089593

Three-dimensional lagrangian approach to the classical relativistic dynamics of directly interacting particles

International Nuclear Information System (INIS)

Gaida, R.P.; Kluchkousky, Ya.B.; Tretyak, V.I.

1987-01-01

In the present report the main attention is paid to the interrelations of various three-dimensional approaches and to the relation of the latter to the Fokker-type action formalism; the problem of the correspondence between three-dimensional descriptions and singular Lagrangian formalism will be shortly concerned. The authors start with the three-dimensional Lagrangian formulation of the classical RDIT. The generality of this formalism enables, similarly as in the non-relativistic case, to consider it as a central link explaining naturally a number of features of other three-dimensional approaches, namely Newtonian (based directly on second order equations of motion) and Hamiltonian ones). It is also capable of describing four-dimensional manifestly covariant models using Fokker action integrals and singular Lagrangians

Oxytocin promotes bone formation during the alveolar healing process in old acyclic female rats.

Science.gov (United States)

Colli, Vilma Clemi; Okamoto, Roberta; Spritzer, Poli Mara; Dornelles, Rita Cássia Menegati

2012-09-01

OT was reported to be a direct regulator of bone mass in young rodents, and this anabolic effect on bone is a peripheral action of OT. The goal of this study was to investigate the peripheral action of oxytocin (OT) in the alveolar healing process in old female rats. Females Wistar rats (24-month-old) in permanent diestrus phase, received two ip (12h apart) injections of saline (NaCl 0.15M - control group) or OT (45μg/rat - treated group). Seven days later, the right maxillary incisor was extracted and analyses were performed up to 28 days of the alveolar healing process (35 days after saline or OT administration). Calcium and phosphorus plasma concentrations did not differ between the groups. The plasma biochemical bone formations markers, alkaline phosphatase (ALP) and osteocalcin were significantly higher in the treated group. Histomorphometric analyses confirmed bone formation as the treated group presented the highest mean value of post-extraction bone formation. Tartrate-resistant acid phosphatase (TRAP) was significantly reduced in the treated group indicating an anti-resorptive effect of OT. Immunohistochemistry reactions performed in order to identify the presence of osteocalcin and TRAP in the bone cells of the dental socket confirmed these outcomes. OT was found to promote bone formation and to inhibit bone resorption in old acyclic female rats during the alveolar healing process. Published by Elsevier Ltd.

Three-dimensional phase-field simulations of directional solidification

Science.gov (United States)

Plapp, Mathis

2007-05-01

The phase-field method has become the method of choice for simulating microstructural pattern formation during solidification. One of its main advantages is that time-dependent three-dimensional simulations become feasible, which makes it possible to address long-standing questions of pattern stability and pattern selection. Here, a brief introduction to the phase-field model and its implementation is given, and its capabilities are illustrated by examples taken from the directional solidification of binary alloys. In particular, the morphological stability of hexagonal cellular arrays and of eutectic lamellar patterns is investigated.

The dimensional nature of eating pathology: Evidence from a direct comparison of categorical, dimensional, and hybrid models.

Science.gov (United States)

Luo, Xiaochen; Donnellan, M Brent; Burt, S Alexandra; Klump, Kelly L

2016-07-01

Eating disorders are conceptualized as categorical rather than dimensional in the current major diagnostic system (Diagnostic and Statistical Manual of Mental Disorders; 5th ed.; American Psychiatric Association, 2013) and in many previous studies. However, previous research has not critically evaluated this assumption or tested hybrid models (e.g., modeling latent variables with both dimensional and categorical features). Accordingly, the current study directly compared categorical, dimensional, and hybrid models for eating pathology in a large, population-based sample. Participants included 3,032 female and male twins (ages 9-30 years) from the Michigan State University Twin Registry. The Minnesota Eating Behaviors Survey was used to assess disordered eating symptoms including body dissatisfaction, weight preoccupation, binge eating, and compensatory behaviors. Results showed that dimensional models best fit the data in the overall sample as well as across subgroups divided by sex and pubertal status (e.g., prepubertal vs. postpubertal). It is interesting to note that the results favored more categorical models when using a case-control subset of our sample with participants who either endorsed substantial eating pathology or no/little eating pathology. Overall, findings provide support for a dimensional conceptualization of eating pathology and underscore the importance of using community samples to capture the full range of severity of eating pathology when investigating questions about taxonomy. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Antiviral activities of 2,6-diaminopurine-based acyclic nucleoside phosphonates against herpesviruses: In vitro study results with pseudorabies virus (PrV, SuHV-1)

Czech Academy of Sciences Publication Activity Database

Zouharová, D.; Lipenská, I.; Fojtiková, M.; Kulich, P.; Neca, J.; Slaný, M.; Kovařčík, K.; Turanek-Knotigová, P.; Hubatka, F.; Celechovská, H.; Mašek, J.; Koudelka, Š.; Procházka, L.; Eyer, L.; Plocková, J.; Bartheldyová, E.; Miller, A. D.; Růžek, Daniel; Raška, M.; Janeba, Zlatko; Turánek, J.

2016-01-01

Roč. 184, FEB 29 (2016), s. 84-93 ISSN 0378-1135 Institutional support: RVO:60077344 ; RVO:61388963 Keywords : Pseudorabies * Acyclic nucleoside phosphonates * DNA viruses * Cidofovir * Antiviral drugs * DNA polymerase Subject RIV: EE - Microbiology, Virology; CC - Organic Chemistry (UOCHB-X) Impact factor: 2.628, year: 2016

The effect of maturation on the configurations of acyclic isoprenoid acids in sediments

Science.gov (United States)

Mackenzie, A. S.; Patience, R. L.; Yon, D. A.; Maxwell, J. R.

1982-05-01

Within a variety of sedimentary rocks of differing maturity, the configurations of a suite of acyclic isoprenoid acids have been examined by gas Chromatographic (in a few cases also by combined gas chromatography-mass spectrometry) analysis of their diastereoisomeric methyl and (-)-menthyl esters. The samples include the Eocene Messel (Germany) and Green River (U.S.) shales, the Permian Irati shale (Brazil) and a number of Lower Toarcian shales from the Paris Basin. The isomer distributions show that isomerisation occurs at the chiral centres with increasing maturation (to increase the number of isomers) and that the rate of isomerisation increases for centres (C-2,C-3) closest to the carboxyl group. These results suggest that adsorption of the carboxyl group to a catalyst surface may control the isomerisation rates by way of access to the catalyst.

The directional propagation characteristics of elastic wave in two-dimensional thin plate phononic crystals

International Nuclear Information System (INIS)

Wen Jihong; Yu, Dianlong; Wang Gang; Zhao Honggang; Liu Yaozong; Wen Xisen

2007-01-01

The directional propagation characteristics of elastic wave during pass bands in two-dimensional thin plate phononic crystals are analyzed by using the lumped-mass method to yield the phase constant surface. The directions and regions of wave propagation in phononic crystals for certain frequencies during pass bands are predicted with the iso-frequency contour lines of the phase constant surface, which are then validated with the harmonic responses of a finite two-dimensional thin plate phononic crystals with 16x16 unit cells. These results are useful for controlling the wave propagation in the pass bands of phononic crystals

Synthesis of New Acadesine (AICA-riboside Analogues Having Acyclic d-Ribityl or 4-Hydroxybutyl Chains in Place of the Ribose

Directory of Open Access Journals (Sweden)

Gennaro Piccialli

2013-08-01

Full Text Available The antiviral activity of certain acyclic nucleosides drew our attention to the fact that the replacement of the furanose ring by an alkyl group bearing hydroxyl(s could be a useful structural modification to modulate the biological properties of those nucleosides. Herein, we report on the synthesis of some novel acadesine analogues, where the ribose moiety is mimicked by a d-ribityl or by a hydroxybutyl chain.

Dynamics of the two-dimensional directed Ising model in the paramagnetic phase

Science.gov (United States)

Godrèche, C.; Pleimling, M.

2014-05-01

We consider the nonconserved dynamics of the Ising model on the two-dimensional square lattice, where each spin is influenced preferentially by its east and north neighbours. The single-spin flip rates are such that the stationary state is Gibbsian with respect to the usual ferromagnetic Ising Hamiltonian. We show the existence, in the paramagnetic phase, of a dynamical transition between two regimes of violation of the fluctuation-dissipation theorem in the nonequilibrium stationary state: a regime of weak violation where the stationary fluctuation-dissipation ratio is finite, when the asymmetry parameter is less than a threshold value, and a regime of strong violation where this ratio vanishes asymptotically above the threshold. This study suggests that this novel kind of dynamical transition in nonequilibrium stationary states, already found for the directed Ising chain and the spherical model with asymmetric dynamics, might be quite general. In contrast with the latter models, the equal-time correlation function for the two-dimensional directed Ising model depends on the asymmetry.

Pd-Catalyzed N-Arylation of Secondary Acyclic Amides: Catalyst Development, Scope, and Computational Study

Science.gov (United States)

Hicks, Jacqueline D.; Hyde, Alan M.; Cuezva, Alberto Martinez; Buchwald, Stephen L.

2009-01-01

We report the efficient N-arylation of acyclic secondary amides and related nucleophiles with aryl nonaflates, triflates, and chlorides. This method allows for easy variation of the aromatic component in tertiary aryl amides. A new biaryl phosphine with P-bound 3,5-(bis)trifluoromethylphenyl groups was found to be uniquely effective for this amidation. The critical aspects of the ligand were explored through synthetic, mechanistic, and computational studies. Systematic variation of the ligand revealed the importance of (1) a methoxy group on the aromatic carbon of the “top ring” ortho to the phosphorus and (2) two highly electron-withdrawing P-bound 3,5-(bis)trifluoromethylphenyl groups. Computational studies suggest the electron-deficient nature of the ligand is important in facilitating amide binding to the LPd(II)(Ph)(X) intermediate. PMID:19886610

Molecular structure and conformation of two acyclic polythioethers: Implications for the design of heavy metal chelators

Energy Technology Data Exchange (ETDEWEB)

Desper, J.M.; Powell, D.R.; Gellman, S.H. (Univ. of Wisconsin, Madison (USA))

1990-05-23

The crystal structures of the 1,9-bis(p-tolyl)-2,5,8-trithianonane (1) and 1,12-bis(p-tolyl)-2,5,8,11-tetrathiadodecane (2) are reported. Previous studies of macrocyclic polythioethers have revealed a pronounced tendency for backbone CS-CC bonds to adopt gauche torsion angles. The same tendency is observed in the homologous acyclic polythioethers 1 and 2, demonstrating that the gauche preference is not simply the result of a macrocyclic constraint. Because of this gauche preference of CS-CC torsion units and the well-established anti preference of SC-CS torsion units, polythioethers constructed from ethylene sulfide subunits are generally far from preorganized for metal ion chelation.

Bioinspired one-dimensional materials for directional liquid transport.

Science.gov (United States)

Ju, Jie; Zheng, Yongmei; Jiang, Lei

2014-08-19

One-dimensional materials (1D) capable of transporting liquid droplets directionally, such as spider silks and cactus spines, have recently been gathering scientists' attention due to their potential applications in microfluidics, textile dyeing, filtration, and smog removal. This remarkable property comes from the arrangement of the micro- and nanostructures on these organisms' surfaces, which have inspired chemists to develop methods to prepare surfaces with similar directional liquid transport ability. In this Account, we report our recent progress in understanding how this directional transport works, as well our advances in the design and fabrication of bioinspired 1D materials capable of transporting liquid droplets directionally. To begin, we first discuss some basic theories on droplet directional movement. Then, we discuss the mechanism of directional transport of water droplets on natural spider silks. Upon contact with water droplets, the spider silk undergoes what is known as a wet-rebuilt, which forms periodic spindle-knots and joints. We found that the resulting gradient of Laplace pressure and surface free energy between the spindle-knots and joints account for the cooperative driving forces to transport water droplets directionally. Next, we discuss the directional transport of water droplets on desert cactus. The integration of multilevel structures of the cactus and the resulting integration of multiple functions together allow the cactus spine to transport water droplets continuously from tip to base. Based on our studies of natural spider silks and cactus spines, we have prepared a series of artificial spider silks (A-SSs) and artificial cactus spines (A-CSs) with various methods. By changing the surface roughness and chemical compositions of the artificial spider silks' spindle-knots, or by introducing stimulus-responsive molecules, such as thermal-responsive and photoresponsive molecules, onto the spindle-knots, we can reversibly manipulate

Polystyrene-Supported Acyclic Diaminocarbene Palladium Complexes in Sonogashira Cross-Coupling: Stability vs. Catalytic Activity

Directory of Open Access Journals (Sweden)

Vladimir N. Mikhaylov

2018-04-01

Full Text Available Two types of immobilized on the amino-functionalized polystyrene-supported acyclic diaminocarbene palladium complexes (ADC-PdII are investigated under Sonogashira cross-coupling conditions. Depending on substituents in the diaminocarbene fragment immobilized ADC-PdII, systems are found to have different catalytic activity and stability regarding Pd-leaching. PdII-diaminocarbenes possessing protons at both nitrogen atoms smoothly decompose into Pd0-containing species providing a catalytic “cocktail system” with high activity and ability to reuse within nine runs. Polymer-supported palladium (II complex bearing NBn–Ccarbene–NH-moiety exhibits greater stability while noticeably lower activity under Sonogashira cross-coupling. Four molecular ADC-PdII complexes are also synthesized and investigated with the aim of confirming proposed base-promoted pathway of ADC-PdII conversion through carbodiimide into an active Pd0 forms.

Direct Measurement of the Band Structure of a Buried Two-Dimensional Electron Gas

DEFF Research Database (Denmark)

Miwa, Jill; Hofmann, Philip; Simmons, Michelle Y.

2013-01-01

We directly measure the band structure of a buried two dimensional electron gas (2DEG) using angle resolved photoemission spectroscopy. The buried 2DEG forms 2 nm beneath the surface of p-type silicon, because of a dense delta-type layer of phosphorus n-type dopants which have been placed there...

Directed batch assembly of three-dimensional helical nanobelts through angular winding and electroplating

International Nuclear Information System (INIS)

Bell, D J; Bauert, T E; Zhang, L; Dong, L X; Sun, Y; Gruetzmacher, D; Nelson, B J

2007-01-01

This paper presents a new technique for the directed batch assembly of rolled-up three-dimensional helical nanobelts. The wet etch time is controlled in order for the loose end of the self-formed SiGe/Si/Cr nanobelts to be located over an electrode by taking advantage of the additional angular winding motion in the lateral direction. In a subsequent Au electroplating step, contacts are electroformed and the batch assembly is completed, while at the same time the conductance of the structures is increased

Bifurcatriol, a New Antiprotozoal Acyclic Diterpene from the Brown Alga Bifurcaria bifurcata

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Vangelis Smyrniotopoulos

2017-08-01

Full Text Available Linear diterpenes that are commonly found in brown algae are of high chemotaxonomic and ecological importance. This study reports bifurcatriol (1, a new linear diterpene featuring two stereogenic centers isolated from the Irish brown alga Bifurcaria bifurcata. The gross structure of this new natural product was elucidated based on its spectroscopic data (IR, 1D and 2D-NMR, HRMS. Its absolute configuration was identified by experimental and computational vibrational circular dichroism (VCD spectroscopy, combined with the calculation of 13C-NMR chemical shielding constants. Bifurcatriol (1 was tested for in vitro antiprotozoal activity towards a small panel of parasites (Plasmodium falciparum, Trypanosoma brucei rhodesiense, T. cruzi, and Leishmania donovani and cytotoxicity against mammalian primary cells. The highest activity was exerted against the malaria parasite P. falciparum (IC50 value 0.65 μg/mL with low cytotoxicity (IC50 value 56.6 μg/mL. To our knowledge, this is the first successful application of VCD and DP4 probability analysis of the calculated 13C-NMR chemical shifts for the simultaneous assignment of the absolute configuration of multiple stereogenic centers in a long-chain acyclic natural product.

Synthesis of modified cyclic and acyclic dextrins and comparison of their complexation ability

Directory of Open Access Journals (Sweden)

Kata Tuza

2014-12-01

Full Text Available We compared the complex forming ability of α-, β- and γ-cyclodextrins (α-CD, β-CD and γ-CD with their open ring analogs. In addition to the native cyclodextrins also modified cyclodextrins and the corresponding maltooligomers, functionalized with neutral 2-hydroxypropyl moieties, were synthesized. A new synthetic route was worked out via bromination, benzylation, deacetylation and debenzylation to obtain the 2-hydroxypropyl maltooligomer counterparts. The complexation properties of non-modified and modified cyclic and acyclic dextrins were studied and compared by photon correlation spectroscopy (PCS and capillary electrophoresis (CE using model guest compounds. In some cases cyclodextrins and their open-ring analogs (acyclodextrins show similar complexation abilities, while with other guests considerably different behavior was observed depending on the molecular dimensions and chemical characteristics of the guests. This was explained by the enhanced flexibility of the non-closed rings. Even the signs of enantiorecognition were observed for the chloropheniramine/hydroxypropyl maltohexaose system. Further studies are planned to help the deeper understanding of the interactions.

Three-dimensional transition in the wake of a circular cylinder by direct numerical simulation

International Nuclear Information System (INIS)

Kang, S. J.; Mo, J. O.; Lee, Y. H.; Tanahashi, M.; Miyauchi, T.

2001-01-01

Three-dimensional time-dependent flow past a circular cylinder is numerically investigated using direct numerical simulation for Reynolds number 280 and 300. The higher-order finite difference scheme is employed for the spatial distributions along with the second order Adams-Bashforth and the first order backward-Euler time integration. In x-y plane, the convection term is applied by the 5th order upwind scheme and the pressure and viscosity terms are applied by the 4th order central difference. And in spanwise, Navier-Stokes equation is distributed using of spectral method. At Reynolds number 259 the two-dimensional wake becomes linearly unstable to a second branch of modes with wavelength about 1.0 diameters at onset (B-mode). Present results of three-dimensional effects of in wake of a circular cylinder is represented with spanwise and streamwise vorticity contours as Reynolds numbers

The direct field boundary impedance of two-dimensional periodic structures with application to high frequency vibration prediction.

Science.gov (United States)

Langley, Robin S; Cotoni, Vincent

2010-04-01

Large sections of many types of engineering construction can be considered to constitute a two-dimensional periodic structure, with examples ranging from an orthogonally stiffened shell to a honeycomb sandwich panel. In this paper, a method is presented for computing the boundary (or edge) impedance of a semi-infinite two-dimensional periodic structure, a quantity which is referred to as the direct field boundary impedance matrix. This terminology arises from the fact that none of the waves generated at the boundary (the direct field) are reflected back to the boundary in a semi-infinite system. The direct field impedance matrix can be used to calculate elastic wave transmission coefficients, and also to calculate the coupling loss factors (CLFs), which are required by the statistical energy analysis (SEA) approach to predicting high frequency vibration levels in built-up systems. The calculation of the relevant CLFs enables a two-dimensional periodic region of a structure to be modeled very efficiently as a single subsystem within SEA, and also within related methods, such as a recently developed hybrid approach, which couples the finite element method with SEA. The analysis is illustrated by various numerical examples involving stiffened plate structures.

Evaluation of Novel Acyclic Nucleoside Phosphonates against Human and Animal Gammaherpesviruses Revealed an Altered Metabolism of Cyclic Prodrugs upon Epstein-Barr Virus Reactivation in P3HR-1 Cells

Czech Academy of Sciences Publication Activity Database

Coen, N.; Duraffour, S.; Naesens, L.; Krečmerová, Marcela; Van Den Oord, J.; Snoeck, R.; Andrei, G.

2013-01-01

Roč. 87, č. 22 (2013), s. 12422-12432 ISSN 0022-538X R&D Projects: GA MPO FR-TI4/625 Institutional support: RVO:61388963 Keywords : acyclic nucleoside phosphonate * gammaherpesvirus * Epstein-Barr virus * Kaposi's sarcoma * HPMP-5-azaC * cidofovir Subject RIV: EE - Microbiology, Virology Impact factor: 4.648, year: 2013

Quantum Secure Direct Communication by Using Three-Dimensional Hyperentanglement

International Nuclear Information System (INIS)

Shi Jin; Gong Yanxiao; Xu Ping; Zhu Shining; Zhan Youbang

2011-01-01

We propose two schemes for realizing quantum secure direct communication (QSDC) by using a set of ordered two-photon three-dimensional hyperentangled states entangled in two degrees of freedom (DOFs) as quantum information channels. In the first scheme, the photons from Bob to Alice are transmitted only once. After insuring the security of the quantum channels, Bob encodes the secret message on his photons. Then Alice performs single-photon two-DOF Bell bases measurements on her photons. This scheme has better security than former QSDC protocols. In the second scheme, Bob transmits photons to Alice twice. After insuring the security of the quantum channels, Bob encodes the secret message on his photons. Then Alice performs two-photon Bell bases measurements on each DOF. The scheme has more information capacity than former QSDC protocols. (general)

Probabilistic Networks

DEFF Research Database (Denmark)

Jensen, Finn Verner; Lauritzen, Steffen Lilholt

2001-01-01

This article describes the basic ideas and algorithms behind specification and inference in probabilistic networks based on directed acyclic graphs, undirected graphs, and chain graphs.......This article describes the basic ideas and algorithms behind specification and inference in probabilistic networks based on directed acyclic graphs, undirected graphs, and chain graphs....

Synthesis and Crystal Structure Determination of a Nickel(II Complex of an Acyclic Pentadentate (N5 Mono Schiff Base Ligand

Directory of Open Access Journals (Sweden)

R. V. Parish

2001-10-01

Full Text Available The asymmetrical tripodal tetraamine ligand N[(CH23NH2]2[(CH22NH2] (ppe was condensed with 2-acetylpyridine in the presence of nickel(II ion. In ethanolwater solution the reaction stops after the first stage of condensation, and a new nickel(II complex of an acyclic pentadentate (N5 mono Schiff base ligand was obtained. X-ray structure analysis of the resulting complex, [Ni(ppe-py(H2O](ClO42, indicates that condensation with 2-acetylpyridine is at the propylene chain of ppe. The geometry around the nickel ion is distorted octahedral in which the sixth co-ordination group is a solvent molecule.

Direct current hopping conductance in one-dimensional diagonal disordered systems

Institute of Scientific and Technical Information of China (English)

Ma Song-Shan; Xu Hui; Liu Xiao-Liang; Xiao Jian-Rong

2006-01-01

Based on a tight-binding disordered model describing a single electron band, we establish a direct current (dc) electronic hopping transport conductance model of one-dimensional diagonal disordered systems, and also derive a dc conductance formula. By calculating the dc conductivity, the relationships between electric field and conductivity and between temperature and conductivity are analysed, and the role played by the degree of disorder in electronic transport is studied. The results indicate the conductivity of systems decreasing with the increase of the degree of disorder, characteristics of negative differential dependence of resistance on temperature at low temperatures in diagonal disordered systems, and the conductivity of systems decreasing with the increase of electric field, featuring the non-Ohm's law conductivity.

Generating Lie Point Symmetry Groups of (2+1)-Dimensional Broer-Kaup Equation via a Simple Direct Method

International Nuclear Information System (INIS)

Ma Hongcai

2005-01-01

Using the (2+1)-dimensional Broer-Kaup equation as an simple example, a new direct method is developed to find symmetry groups and symmetry algebras and then exact solutions of nonlinear mathematical physical equations.

Direct write printing of three-dimensional ZrO2 biological scaffolds

International Nuclear Information System (INIS)

Li, Ya-yun; Li, Long-tu; Li, Bo

2015-01-01

Graphical abstract: Three-dimensional (3D) zirconium dioxide (ZrO 2 ) scaffolds have been fabricated for biological engineering by direct write printing method. The water-based ZrO 2 ink with a solid content fraction of 70 wt% was deposited through a fine nozzle on the substrate by a layer-by-layer sequence to produce the 3D microperiodic structures. Under a microscope, the proliferation of HCT116 cells can be observed around the 3D ZrO 2 scaffolds. 3D porous internal architecture is beneficial for cell growth by providing more locations for cell attachment and proliferation. The largest value of compressive strength reached 10 MPa, which is more than that of the hydroxyapatite (HAp) scaffold. The ability of printing 3D scaffolds with the high precise control of their internal architecture is the unique characteristics performed by the direct write technique, which will provide potential application of biomaterials and tissue engineering scaffolds. (a) Top view of the sintered 3D woodpile ZrO 2 scaffold; (b) top view of the sintered 3D cylindrical ZrO 2 scaffold. - Highlights: • 3D cylindrical and woodpile ZrO 2 scaffolds were fabricated by direct write printing method. • The compressive strength of the sample with porosity about 63% was 8 MPa. • The compressive strength of the porosity 55% sample was 10 MPa. • 3D porous ZrO 2 scaffolds with interconnected architecture are beneficial for cell attachment and proliferation. - Abstract: Three-dimensional (3D) zirconium dioxide (ZrO 2 ) scaffolds have been fabricated for biological engineering by direct write printing method. The water-based ZrO 2 ink with a solid content fraction of 70 wt% was deposited through a fine nozzle on the substrate by a layer-by-layer sequence to produce the 3D microperiodic structures. The preparation and the rheological behavior of this ink, as well as the principles of the direct write printing process were investigated systematically. Sintered at 1250 °C for 4 h was the optimal

Application of three-dimensional reduced graphene oxide-gold composite modified electrode for direct electrochemistry and electrocatalysis of myoglobin

International Nuclear Information System (INIS)

Shi, Fan; Xi, Jingwen; Hou, Fei; Han, Lin; Li, Guangjiu; Gong, Shixing; Chen, Chanxing; Sun, Wei

2016-01-01

In this paper a three-dimensional (3D) reduced graphene oxide (RGO) and gold (Au) composite was synthesized by electrodeposition and used for the electrode modification with carbon ionic liquid electrode (CILE) as the substrate electrode. Myoglobin (Mb) was further immobilized on the surface of 3D RGO–Au/CILE to obtain an electrochemical sensing platform. Direct electrochemistry of Mb on the modified electrode was investigated with a pair of well-defined redox waves appeared on cyclic voltammogram, indicating the realization of direct electron transfer of Mb with the modified electrode. The results can be ascribed to the presence of highly conductive 3D RGO–Au composite on the electrode surface that accelerate the electron transfer rate between the electroactive center of Mb and the electrode. The Mb modified electrode showed excellent electrocatalytic activity to the reduction of trichloroacetic acid in the concentration range from 0.2 to 36.0 mmol/L with the detection limit of 0.06 mmol/L (3σ). - Graphical abstract: Direct electrochemistry of myoglobin was realized on a three-dimensional reduced graphene oxide and gold nanocomposite modified carbon ionic liquid electrode. - Highlights: • A three-dimensional reduced graphene oxide and gold composite was synthesized by electrodeposition. • Myoglobin was immobilized on the modified electrode to obtain an electrochemical sensor. • Direct electrochemistry of myoglobin was realized on the modified electrode. • The myoglobin modified electrode showed excellent electrocatalytic reduction to trichloroacetic acid.

Dimensional and material characteristics of direct deposited tool steel by CO II laser

Science.gov (United States)

Choi, J.

2006-01-01

Laser aided direct metalimaterial deposition (DMD) process builds metallic parts layer-by-layer directly from the CAD representation. In general, the process uses powdered metaUmaterials fed into a melt pool, creating fully dense parts. Success of this technology in the die and tool industry depends on the parts quality to be achieved. To obtain designed geometric dimensions and material properties, delicate control of the parameters such as laser power, spot diameter, traverse speed and powder mass flow rate is critical. In this paper, the dimensional and material characteristics of directed deposited H13 tool steel by CO II laser are investigated for the DMD process with a feedback height control system. The relationships between DMD process variables and the product characteristics are analyzed using statistical techniques. The performance of the DMD process is examined with the material characteristics of hardness, porosity, microstructure, and composition.

Three dimensional Free Vibration and Transient Analysis of Two Directional Functionally Graded Thick Cylindrical Panels Under Impact Loading

Directory of Open Access Journals (Sweden)

Hassan Zafarmand

Full Text Available AbstractIn this paper three dimensional free vibration and transient response of a cylindrical panel made of two directional functionally graded materials (2D-FGMs based on three dimensional equations of elasticity and subjected to internal impact loading is considered. Material properties vary through both radial and axial directions continuously. The 3D graded finite element method (GFEM based on Rayleigh-Ritz energy formulation and Newmark direct integration method has been applied to solve the equations in space and time domains. The fundamental normalized natural frequency, time history of displacements and stresses in three directions and velocity of radial stress wave propagation for various values of span angel of cylindrical panel and different power law exponents have been investigated. The present results show that using 2D-FGMs leads to a more flexible design than conventional 1D-FGMs. The GFEM solution have been compared with the results of an FG thick hollow cylinder and an FG curved panel, where a good agreement between them is observed.

Three dimensional graphene transistor for ultra-sensitive pH sensing directly in biological media

International Nuclear Information System (INIS)

Ameri, Shideh Kabiri; Singh, Pramod K.; Sonkusale, Sameer R.

2016-01-01

In this work, pH sensing directly in biological media using three dimensional liquid gated graphene transistors is presented. The sensor is made of suspended network of graphene coated all around with thin layer of hafnium oxide (HfO_2), showing high sensitivity and sensing beyond the Debye-screening limit. The performance of the pH sensor is validated by measuring the pH of isotonic buffered, Dulbecco's phosphate buffered saline (DPBS) solution, and of blood serum derived from Sprague-Dawley rat. The pH sensor shows high sensitivity of 71 ± 7 mV/pH even in high ionic strength media with molarities as high as 289 ± 1 mM. High sensitivity of this device is owing to suspension of three dimensional graphene in electrolyte which provides all around liquid gating of graphene, leading to higher electrostatic coupling efficiency of electrolyte to the channel and higher gating control of transistor channel by ions in the electrolyte. Coating graphene with hafnium oxide film (HfO_2) provides binding sites for hydrogen ions, which results in higher sensitivity and sensing beyond the Debye-screening limit. The 3D graphene transistor offers the possibility of real-time pH measurement in biological media without the need for desaltation or sample preparation. - Graphical abstract: (a) Test setup – Direct rat blood serum pH measurements (b) Measured transfer characteristics of the transistor for blood serum at different pH values, and (c) Zoomed in version around direct point. - Highlights: • A three-dimensional graphene transistor for pH sensing is presented. • It shows sensitivity of 71 ± 7 mV/pH even in high ionic strength media. • High sensitivity attributed to 3D foam structure and all-around liquid gating. • Enables real-time pH sensing in biological media without need of desaltation.

Three dimensional graphene transistor for ultra-sensitive pH sensing directly in biological media

Energy Technology Data Exchange (ETDEWEB)

Ameri, Shideh Kabiri; Singh, Pramod K.; Sonkusale, Sameer R., E-mail: sameer@ece.tufts.edu

2016-08-31

In this work, pH sensing directly in biological media using three dimensional liquid gated graphene transistors is presented. The sensor is made of suspended network of graphene coated all around with thin layer of hafnium oxide (HfO{sub 2}), showing high sensitivity and sensing beyond the Debye-screening limit. The performance of the pH sensor is validated by measuring the pH of isotonic buffered, Dulbecco's phosphate buffered saline (DPBS) solution, and of blood serum derived from Sprague-Dawley rat. The pH sensor shows high sensitivity of 71 ± 7 mV/pH even in high ionic strength media with molarities as high as 289 ± 1 mM. High sensitivity of this device is owing to suspension of three dimensional graphene in electrolyte which provides all around liquid gating of graphene, leading to higher electrostatic coupling efficiency of electrolyte to the channel and higher gating control of transistor channel by ions in the electrolyte. Coating graphene with hafnium oxide film (HfO{sub 2}) provides binding sites for hydrogen ions, which results in higher sensitivity and sensing beyond the Debye-screening limit. The 3D graphene transistor offers the possibility of real-time pH measurement in biological media without the need for desaltation or sample preparation. - Graphical abstract: (a) Test setup – Direct rat blood serum pH measurements (b) Measured transfer characteristics of the transistor for blood serum at different pH values, and (c) Zoomed in version around direct point. - Highlights: • A three-dimensional graphene transistor for pH sensing is presented. • It shows sensitivity of 71 ± 7 mV/pH even in high ionic strength media. • High sensitivity attributed to 3D foam structure and all-around liquid gating. • Enables real-time pH sensing in biological media without need of desaltation.

Direct measurement of the fluorescence characteristics of aquatic humic substances by a three-dimensional fluorescence spectrophotometer

International Nuclear Information System (INIS)

Nagao, Seiya; Senoo, Muneaki; Suzuki, Yasuhiro; Nakaguchi, Yuzuru; Hiraki, Keizo.

1997-01-01

Humic substances play an important role in the transport of trace metals and insoluble organic materials. They are also considered to be precursors of trihalomethane in aquatic environments. The direct measurement of humic substances was carried out with a three-dimensional fluorescence spectrophotometer after filtering natural-water samples through a GF/F glass fiber filter. Because the influence of the humic concentration, pH and ionic strength on the three-dimensional excitation emission matrix spectra is negligible, the proposed method can be directly applied to the characterization of humic substances in freshwater samples (humic concentration 0.5-10 mg 1 -1 , pH6-9 and ionic strength <0.04 M) and sea-water samples (ionic strength 0.75 M). Humic substances in river, lake and pore water samples exhibit 2-3 peaks at excitation 305-340 nm/emission 415-440 nm and excitation 250-270 nm/emission 440-450 nm. These peak positions correspond to those of fulvic acids isolated from soil. (author)

A novel 13 residue acyclic peptide from the marine snail, Conus monile, targets potassium channels.

Science.gov (United States)

Sudarslal, Sadasivannair; Singaravadivelan, Govindaswamy; Ramasamy, Palanisamy; Ananda, Kuppanna; Sarma, Siddhartha P; Sikdar, Sujit K; Krishnan, K S; Balaram, Padmanabhan

2004-05-07

A novel 13-residue peptide Mo1659 has been isolated from the venom of a vermivorous cone snail, Conus monile. HPLC fractions of the venom extract yielded an intense UV absorbing fraction with a mass of 1659Da. De novo sequencing using both matrix assisted laser desorption and ionization and electrospray MS/MS methods together with analysis of proteolytic fragments successfully yielded the amino acid sequence, FHGGSWYRFPWGY-NH(2). This was further confirmed by comparison with the chemically synthesized peptide and by conventional Edman sequencing. Mo1659 has an unusual sequence with a preponderance of aromatic residues and the absence of apolar, aliphatic residues like Ala, Val, Leu, and Ile. Mo1659 has no disulfide bridges distinguishing it from the conotoxins and bears no sequence similarity with any of the acyclic peptides isolated thus far from the venom of cone snails. Electrophysiological studies on the effect of Mo1659 on measured currents in dorsal root ganglion neurons suggest that the peptide targets non-inactivating voltage-dependent potassium channels.

Acyclic Diene Metathesis (ADMET Polymerization for Precise Synthesis of Defect-Free Conjugated Polymers with Well-Defined Chain Ends

Directory of Open Access Journals (Sweden)

Tahmina Haque

2015-03-01

Full Text Available This accounts introduces unique characteristics by adopting the acyclic diene metathesis (ADMET polymerization for synthesis of conjugated polymers, poly(arylene vinylenes, known as promising molecular electronics. The method is more suitable than the other methods in terms of atom efficiency affording defect-free, stereo-regular (exclusive trans polymers with well-defined chain ends; the resultant polymers possess better property than those prepared by the conventional methods. The chain ends (vinyl group in the resultant polymer prepared by ruthenium-carbene catalyst(s can be modified by treating with molybdenum-alkylidene complex (olefin metathesis followed by addition of various aldehyde (Wittig type cleavage, affording the end-functionalized polymers exclusively. An introduction of initiating fragment, the other conjugated segment, and one-pot synthesis of end-functionalized block copolymers, star shape polymers can be achieved by adopting this methodology.

Direct Linear System Identification Method for Multistory Three-dimensional Building Structure with General Eccentricity

OpenAIRE

Shintani, Kenichirou; Yoshitomi, Shinta; Takewaki, Izuru

2017-01-01

A method of physical parameter system identification (SI) is proposed here for three-dimensional (3D) building structures with in-plane rigid floors in which the stiffness and damping coefficients of each structural frame in the 3D building structure are identified from the measured floor horizontal accelerations. A batch processing least-squares estimation method for many discrete time domain measured data is proposed for the direct identification of the stiffness and damping coefficients of...

Direct numerical simulation of steady state, three dimensional, laminar flow around a wall mounted cube

Science.gov (United States)

Liakos, Anastasios; Malamataris, Nikolaos

2014-11-01

The topology and evolution of flow around a surface mounted cubical object in three dimensional channel flow is examined for low to moderate Reynolds numbers. Direct numerical simulations were performed via a home made parallel finite element code. The computational domain has been designed according to actual laboratory experimental conditions. Analysis of the results is performed using the three dimensional theory of separation. Our findings indicate that a tornado-like vortex by the side of the cube is present for all Reynolds numbers for which flow was simulated. A horse-shoe vortex upstream from the cube was formed at Reynolds number approximately 1266. Pressure distributions are shown along with three dimensional images of the tornado-like vortex and the horseshoe vortex at selected Reynolds numbers. Finally, and in accordance to previous work, our results indicate that the upper limit for the Reynolds number for which steady state results are physically realizable is roughly 2000. Financial support of author NM from the Office of Naval Research Global (ONRG-VSP, N62909-13-1-V016) is acknowledged.

Direct linearizing transform for three-dimensional discrete integrable systems: the lattice AKP, BKP and CKP equations.

Science.gov (United States)

Fu, Wei; Nijhoff, Frank W

2017-07-01

A unified framework is presented for the solution structure of three-dimensional discrete integrable systems, including the lattice AKP, BKP and CKP equations. This is done through the so-called direct linearizing transform, which establishes a general class of integral transforms between solutions. As a particular application, novel soliton-type solutions for the lattice CKP equation are obtained.

Identification of a carotenoid oxygenase synthesizing acyclic xanthophylls: combinatorial biosynthesis and directed evolution.

Science.gov (United States)

Mijts, Benjamin N; Lee, Pyung Cheon; Schmidt-Dannert, Claudia

2005-04-01

A carotenoid desaturase homolog from Staphylococcus aureus (CrtOx) was identified. When expressed in engineered E. coli cells synthesizing linear C(30) carotenoids, polar carotenoid products were generated, identified as aldehyde and carboxylic acid C(30) carotenoid derivatives. The major product in this engineered pathway is the fully desaturated C(30) dialdehyde carotenoid 4,4'-diapolycopen-4,4'-dial. Very low carotenoid yields were observed when CrtOx was complemented with the C(40) carotenoid lycopene pathway. But extension of an in vitro evolved pathway of the fully desaturated 2,4,2',4'-tetradehydrolycopene produced the structurally novel fully desaturated C(40) dialdehyde carotenoid 2,4,2',4'-tetradehydrolycopendial. Directed evolution of CrtOx by error-prone PCR resulted in a number of variants with higher activity on C(40) carotenoid substrates and improved product profiles. These findings may provide new biosynthetic routes to highly polar carotenoids with unique spectral properties desirable for a number of industrial and pharmaceutical applications.

Three-dimensional anode engineering for the direct methanol fuel cell

Energy Technology Data Exchange (ETDEWEB)

Bauer, A.; Oloman, C.W.; Gyenge, E.L. [Department of Chemical and Biological Engineering, The University of British Columbia, 2360 East Mall, Vancouver, BC (Canada)

2009-09-05

Catalyzed graphite felt three-dimensional anodes were investigated in direct methanol fuel cells (DMFCs) operated with sulfuric acid supporting electrolyte. With a conventional serpentine channel flow field the preferred anode thickness was 100 {mu}m, while a novel flow-by anode showed the best performance with a thickness of 200-300 {mu}m. The effects of altering the methanol concentration, anolyte flow rate and operating temperature on the fuel cell superficial power density were studied by full (2{sup 3} + 1) factorial experiments on a cell with anode area of 5 cm{sup 2} and excess oxidant O{sub 2} at 200 kPa(abs). For operation in the flow-by mode with 2 M methanol at 2 cm{sup 3} min{sup -1} and 353 K the peak power density was 2380 W m{sup -2} with a PtRuMo anode catalyst, while a PtRu catalyst yielded 2240 W m{sup -2} under the same conditions. (author)

Three-dimensional anode engineering for the direct methanol fuel cell

Science.gov (United States)

Bauer, A.; Oloman, C. W.; Gyenge, E. L.

Catalyzed graphite felt three-dimensional anodes were investigated in direct methanol fuel cells (DMFCs) operated with sulfuric acid supporting electrolyte. With a conventional serpentine channel flow field the preferred anode thickness was 100 μm, while a novel flow-by anode showed the best performance with a thickness of 200-300 μm. The effects of altering the methanol concentration, anolyte flow rate and operating temperature on the fuel cell superficial power density were studied by full (2 3 + 1) factorial experiments on a cell with anode area of 5 cm 2 and excess oxidant O 2 at 200 kPa(abs). For operation in the flow-by mode with 2 M methanol at 2 cm 3 min -1 and 353 K the peak power density was 2380 W m -2 with a PtRuMo anode catalyst, while a PtRu catalyst yielded 2240 W m -2 under the same conditions.

Single-phase multi-dimensional thermohydraulics direct numerical simulation code DINUS-3. Input data description

Energy Technology Data Exchange (ETDEWEB)

Muramatsu, Toshiharu [Power Reactor and Nuclear Fuel Development Corp., Oarai, Ibaraki (Japan). Oarai Engineering Center

1998-08-01

This report explains the numerical methods and the set-up method of input data for a single-phase multi-dimensional thermohydraulics direct numerical simulation code DINUS-3 (Direct Numerical Simulation using a 3rd-order upwind scheme). The code was developed to simulate non-stationary temperature fluctuation phenomena related to thermal striping phenomena, developed at Power Reactor and Nuclear Fuel Development Corporation (PNC). The DINUS-3 code was characterized by the use of a third-order upwind scheme for convection terms in instantaneous Navier-Stokes and energy equations, and an adaptive control system based on the Fuzzy theory to control time step sizes. Author expect this report is very useful to utilize the DINUS-3 code for the evaluation of various non-stationary thermohydraulic phenomena in reactor applications. (author)

Quantum centrality testing on directed graphs via P T -symmetric quantum walks

Science.gov (United States)

Izaac, J. A.; Wang, J. B.; Abbott, P. C.; Ma, X. S.

2017-09-01

Various quantum-walk-based algorithms have been proposed to analyze and rank the centrality of graph vertices. However, issues arise when working with directed graphs: the resulting non-Hermitian Hamiltonian leads to nonunitary dynamics, and the total probability of the quantum walker is no longer conserved. In this paper, we discuss a method for simulating directed graphs using P T -symmetric quantum walks, allowing probability-conserving nonunitary evolution. This method is equivalent to mapping the directed graph to an undirected, yet weighted, complete graph over the same vertex set, and can be extended to cover interdependent networks of directed graphs. Previous work has shown centrality measures based on the continuous-time quantum walk provide an eigenvectorlike quantum centrality; using the P T -symmetric framework, we extend these centrality algorithms to directed graphs with a significantly reduced Hilbert space compared to previous proposals. In certain cases, this centrality measure provides an advantage over classical algorithms used in network analysis, for example, by breaking vertex rank degeneracy. Finally, we perform a statistical analysis over ensembles of random graphs, and show strong agreement with the classical PageRank measure on directed acyclic graphs.

Design and Synthesis of Novel Antimicrobial Acyclic and Heterocyclic Dyes and Their Precursors for Dyeing and/or Textile Finishing Based on 2-N-Acylamino-4,5,6,7-tetrahydro-benzo[b]thiophene Systems

Directory of Open Access Journals (Sweden)

Rafat Milad Mohareb

2011-07-01

Full Text Available A series of novel polyfunctionalized acyclic and heterocyclic dye precursors and their respective azo (hydrazone counterpart dyes and dye precursors based on conjugate enaminones and/or enaminonitrile moieties were synthesized. The dyes and their precursors are based on 2-cyano-N-(3-cyano-4,5,6,7-tetrahydrobenzo[b]thiophen-2-yl-acetamide, 2-ethoxycarbonyl-N-(3-cyano-4,5,6,7-tetrahydrobenzo[b]thiophen-2-yl-acetamide or 2-phenylcarbamoyl-N-(3-cyano-4,5,6,7-tetrahydrobenzo[b]thiophen-2-yl-acetamide systems as precursors. The latter compounds were used to synthesize polyfunctional thiophene-, thiazole-, pyrazole, pyridine-, pyrimidine-, oxazine-, as well as acyclic moieties. The dyes and dye precursors were characterized by elemental analysis and spectral methods. All dyes and their precursors were screened in vitro and evaluated for both their antibacterial and antifungal activities. MIC data of the novel dye systems and their respective precursors showed significant antimicrobial activity against most tested organisms. Some compounds exhibited comparable or even higher efficiency than selected standards. Dyes were applied at 5% depth for disperse dyeing of nylon, acetate and polyester fabrics. Their spectral characteristics and fastness properties were measured and evaluated.

An integrated QSAR-PBK/D modelling approach for predicting detoxification and DNA adduct formation of 18 acyclic food-borne α,β-unsaturated aldehydes

Energy Technology Data Exchange (ETDEWEB)

Kiwamoto, R., E-mail: reiko.kiwamoto@wur.nl; Spenkelink, A.; Rietjens, I.M.C.M.; Punt, A.

2015-01-01

Acyclic α,β-unsaturated aldehydes present in food raise a concern because the α,β-unsaturated aldehyde moiety is considered a structural alert for genotoxicity. However, controversy remains on whether in vivo at realistic dietary exposure DNA adduct formation is significant. The aim of the present study was to develop physiologically based kinetic/dynamic (PBK/D) models to examine dose-dependent detoxification and DNA adduct formation of a group of 18 food-borne acyclic α,β-unsaturated aldehydes without 2- or 3-alkylation, and with no more than one conjugated double bond. Parameters for the PBK/D models were obtained using quantitative structure–activity relationships (QSARs) defined with a training set of six selected aldehydes. Using the QSARs, PBK/D models for the other 12 aldehydes were defined. Results revealed that DNA adduct formation in the liver increases with decreasing bulkiness of the molecule especially due to less efficient detoxification. 2-Propenal (acrolein) was identified to induce the highest DNA adduct levels. At realistic dietary intake, the predicted DNA adduct levels for all aldehydes were two orders of magnitude lower than endogenous background levels observed in disease free human liver, suggesting that for all 18 aldehydes DNA adduct formation is negligible at the relevant levels of dietary intake. The present study provides a proof of principle for the use of QSAR-based PBK/D modelling to facilitate group evaluations and read-across in risk assessment. - Highlights: • Physiologically based in silico models were made for 18 α,β-unsaturated aldehydes. • Kinetic parameters were determined by in vitro incubations and a QSAR approach. • DNA adduct formation was negligible at levels relevant for dietary intake. • The use of QSAR-based PBK/D modelling facilitates group evaluations and read-across.

A three-dimensional non-isothermal model for a membraneless direct methanol redox fuel cell

Science.gov (United States)

Wei, Lin; Yuan, Xianxia; Jiang, Fangming

2018-05-01

In the membraneless direct methanol redox fuel cell (DMRFC), three-dimensional electrodes contribute to the reduction of methanol crossover and the open separator design lowers the system cost and extends its service life. In order to better understand the mechanisms of this configuration and further optimize its performance, the development of a three-dimensional numerical model is reported in this work. The governing equations of the multi-physics field are solved based on computational fluid dynamics methodology, and the influence of the CO2 gas is taken into consideration through the effective diffusivities. The numerical results are in good agreement with experimental data, and the deviation observed for cases of large current density may be related to the single-phase assumption made. The three-dimensional electrode is found to be effective in controlling methanol crossover in its multi-layer structure, while it also increases the flow resistance for the discharging products. It is found that the current density distribution is affected by both the electronic conductivity and the concentration of reactants, and the temperature rise can be primarily attributed to the current density distribution. The sensitivity and reliability of the model are analyzed through the investigation of the effects of cell parameters, including porosity values of gas diffusion layers and catalyst layers, methanol concentration and CO2 volume fraction, on the polarization characteristics.

Parallel Factor-Based Model for Two-Dimensional Direction Estimation

Directory of Open Access Journals (Sweden)

Nizar Tayem

2017-01-01

Full Text Available Two-dimensional (2D Direction-of-Arrivals (DOA estimation for elevation and azimuth angles assuming noncoherent, mixture of coherent and noncoherent, and coherent sources using extended three parallel uniform linear arrays (ULAs is proposed. Most of the existing schemes have drawbacks in estimating 2D DOA for multiple narrowband incident sources as follows: use of large number of snapshots, estimation failure problem for elevation and azimuth angles in the range of typical mobile communication, and estimation of coherent sources. Moreover, the DOA estimation for multiple sources requires complex pair-matching methods. The algorithm proposed in this paper is based on first-order data matrix to overcome these problems. The main contributions of the proposed method are as follows: (1 it avoids estimation failure problem using a new antenna configuration and estimates elevation and azimuth angles for coherent sources; (2 it reduces the estimation complexity by constructing Toeplitz data matrices, which are based on a single or few snapshots; (3 it derives parallel factor (PARAFAC model to avoid pair-matching problems between multiple sources. Simulation results demonstrate the effectiveness of the proposed algorithm.

Three-dimensional direct laser written graphitic electrical contacts to randomly distributed components

Science.gov (United States)

Dorin, Bryce; Parkinson, Patrick; Scully, Patricia

2018-04-01

The development of cost-effective electrical packaging for randomly distributed micro/nano-scale devices is a widely recognized challenge for fabrication technologies. Three-dimensional direct laser writing (DLW) has been proposed as a solution to this challenge, and has enabled the creation of rapid and low resistance graphitic wires within commercial polyimide substrates. In this work, we utilize the DLW technique to electrically contact three fully encapsulated and randomly positioned light-emitting diodes (LEDs) in a one-step process. The resolution of the contacts is in the order of 20 μ m, with an average circuit resistance of 29 ± 18 kΩ per LED contacted. The speed and simplicity of this technique is promising to meet the needs of future microelectronics and device packaging.

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

Science.gov (United States)

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

Executive Summary of Ares V: Lunar Capabilities Concept Review Through Phase A-Cycle 3

Science.gov (United States)

Holladay, J. B.; Baggett, K. E.; Feldman, S. M.

2011-01-01

This Technical Memorandum (TM) was generated as an overall Ares V summary from the Lunar Capabilities Concept Review (LCCR) through Phase A-Cycle 3 (PA-C3) with the intent that it may be coupled with separately published appendices for a more detailed, integrated narrative. The Ares V has evolved from the initial point of departure (POD) 51.00.48 LCCR configuration to the current candidate POD, PA-C3D, and the family of vehicles concept that contains vehicles PA-C3A through H. The logical progression from concept to POD vehicles is summarized in this TM and captures the trade space and performance of each. The family-of-vehicles concept was assessed during PA-C3 and offered flexibility in the path forward with the ability to add options deemed appropriate. A description of each trade space is given in addition to a summary of each Ares V element. The Ares V contributions to a Mars campaign are also highlighted with the goal of introducing Ares V capabilities within the trade space. The assessment of the Ares V vehicle as it pertains to Mars missions remained locked to the architecture presented in Mars Design Reference Authorization 5.0 using the PA-C3D vehicle configuration to assess Mars transfer vehicle options, in-space EDS capabilities, docking adaptor and propellant transfer assessments, and lunar and Mars synergistic potential.

Absolute Negative Resistance Induced by Directional Electron-Electron Scattering in a Two-Dimensional Electron Gas

Science.gov (United States)

Kaya, Ismet I.; Eberl, Karl

2007-05-01

A three-terminal device formed by two electrostatic barriers crossing an asymmetrically patterned two-dimensional electron gas displays an unusual potential depression at the middle contact, yielding absolute negative resistance. The device displays momentum and current transfer ratios that far exceed unity. The observed reversal of the current or potential in the middle terminal can be interpreted as the analog of Bernoulli’s effect in a Fermi liquid. The results are explained by directional scattering of electrons in two dimensions.

Bi-directional evolutionary structural optimization for strut-and-tie modelling of three-dimensional structural concrete

Science.gov (United States)

Shobeiri, Vahid; Ahmadi-Nedushan, Behrouz

2017-12-01

This article presents a method for the automatic generation of optimal strut-and-tie models in reinforced concrete structures using a bi-directional evolutionary structural optimization method. The methodology presented is developed for compliance minimization relying on the Abaqus finite element software package. The proposed approach deals with the generation of truss-like designs in a three-dimensional environment, addressing the design of corbels and joints as well as bridge piers and pile caps. Several three-dimensional examples are provided to show the capabilities of the proposed framework in finding optimal strut-and-tie models in reinforced concrete structures and verifying its efficiency to cope with torsional actions. Several issues relating to the use of the topology optimization for strut-and-tie modelling of structural concrete, such as chequerboard patterns, mesh-dependency and multiple load cases, are studied. In the last example, a design procedure for detailing and dimensioning of the strut-and-tie models is given according to the American Concrete Institute (ACI) 318-08 provisions.

New high accuracy super stable alternating direction implicit methods for two and three dimensional hyperbolic damped wave equations

Directory of Open Access Journals (Sweden)

R.K. Mohanty

2014-01-01

Full Text Available In this paper, we report new three level implicit super stable methods of order two in time and four in space for the solution of hyperbolic damped wave equations in one, two and three space dimensions subject to given appropriate initial and Dirichlet boundary conditions. We use uniform grid points both in time and space directions. Our methods behave like fourth order accurate, when grid size in time-direction is directly proportional to the square of grid size in space-direction. The proposed methods are super stable. The resulting system of algebraic equations is solved by the Gauss elimination method. We discuss new alternating direction implicit (ADI methods for two and three dimensional problems. Numerical results and the graphical representation of numerical solution are presented to illustrate the accuracy of the proposed methods.

Fabrication and optical characteristics of silicon-based two-dimensional wavelength division multiplexing splitter with photonic crystal directional waveguide couplers

International Nuclear Information System (INIS)

Liu, Cheng-Yang

2011-01-01

Photonic crystals have many potential applications because of their ability to control lightwave propagation. We report on the fabrication and optical properties of quasi-two-dimensional photonic crystals with triangular lattice of dielectric rods in air. Rod-type photonic crystal structures were fabricated in silicon by electron beam lithography and dry-etching techniques. Wavelength division multiplexing splitters were fabricated from two-dimensional photonic crystal directional waveguide couplers. Transmission spectra were measured and device operation was shown to be in agreement with theoretical calculations. The splitters can be used in visible light region. Such an approach to photonic element systems should enable new applications for designing components in photonic integrated circuits. -- Highlights: → We report the fabrication and optical properties of rod-type photonic crystal. → The splitter was fabricated by electron beam lithography and dry-etching techniques. → The splitter was composed of directional waveguide couplers. → Measured transmission spectra are in agreement with theoretical calculations. → The splitters can be used in visible light region.

High-resolution computer-generated reflection holograms with three-dimensional effects written directly on a silicon surface by a femtosecond laser.

Science.gov (United States)

Wædegaard, Kristian J; Balling, Peter

2011-02-14

An infrared femtosecond laser has been used to write computer-generated holograms directly on a silicon surface. The high resolution offered by short-pulse laser ablation is employed to write highly detailed holograms with resolution up to 111 kpixels/mm2. It is demonstrated how three-dimensional effects can be realized in computer-generated holograms. Three-dimensional effects are visualized as a relative motion between different parts of the holographic reconstruction, when the hologram is moved relative to the reconstructing laser beam. Potential security applications are briefly discussed.

Acyclic cucurbit[n]uril-type molecular containers: influence of glycoluril oligomer length on their function as solubilizing agents.

Science.gov (United States)

Gilberg, Laura; Zhang, Ben; Zavalij, Peter Y; Sindelar, Vladimir; Isaacs, Lyle

2015-04-07

We present the synthesis of a series of six new glycoluril derived molecular clips and acyclic CB[n]-type molecular containers (1–3) that all feature SO3(−) solubilizing groups but differ in the number of glycoluril rings between the two terminal dialkoxyaromatic sidewalls. We report the X-ray crystal structure of 3b which shows that its dialkoxynaphthalene sidewalls actively define a hydrophobic cavity with high potential to engage in π–π interactions with insoluble aromatic guests. Compounds 1–3 possess very good solubility characteristics (≥38 mM) and undergo only very weak self-association (Ks containers 3a and 3b which feature three glycoluril rings between the terminal dialkoxy-o-xylylene and dialkoxynaphthalene sidewalls are less efficient solubilizing agents than 4a and 4b because of their smaller hydrophobic cavities. Containers 1 and 2 behave as molecular clip type receptors and therefore possess the ability to bind to and thereby solubilize aromatic drugs like camptothecin, ziprasidone, and PBS-1086.

Extracting quantitative three-dimensional unsteady flow direction from tuft flow visualizations

Energy Technology Data Exchange (ETDEWEB)

Omata, Noriyasu; Shirayama, Susumu, E-mail: omata@nakl.t.u-tokyo.ac.jp, E-mail: sirayama@sys.t.u-tokyo.ac.jp [Department of Systems Innovation, School of Engineering, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo, 113-8656 (Japan)

2017-10-15

We focus on the qualitative but widely used method of tuft flow visualization, and propose a method for quantifying it using information technology. By applying stereo image processing and computer vision, the three-dimensional (3D) flow direction in a real environment can be obtained quantitatively. In addition, we show that the flow can be divided temporally by performing appropriate machine learning on the data. Acquisition of flow information in real environments is important for design development, but it is generally considered difficult to apply simulations or quantitative experiments to such environments. Hence, qualitative methods including the tuft method are still in use today. Although attempts have been made previously to quantify such methods, it has not been possible to acquire 3D information. Furthermore, even if quantitative data could be acquired, analysis was often performed empirically or qualitatively. In contrast, we show that our method can acquire 3D information and analyze the measured data quantitatively. (paper)

Extracting quantitative three-dimensional unsteady flow direction from tuft flow visualizations

International Nuclear Information System (INIS)

Omata, Noriyasu; Shirayama, Susumu

2017-01-01

We focus on the qualitative but widely used method of tuft flow visualization, and propose a method for quantifying it using information technology. By applying stereo image processing and computer vision, the three-dimensional (3D) flow direction in a real environment can be obtained quantitatively. In addition, we show that the flow can be divided temporally by performing appropriate machine learning on the data. Acquisition of flow information in real environments is important for design development, but it is generally considered difficult to apply simulations or quantitative experiments to such environments. Hence, qualitative methods including the tuft method are still in use today. Although attempts have been made previously to quantify such methods, it has not been possible to acquire 3D information. Furthermore, even if quantitative data could be acquired, analysis was often performed empirically or qualitatively. In contrast, we show that our method can acquire 3D information and analyze the measured data quantitatively. (paper)

Integrating high dimensional bi-directional parsing models for gene mention tagging.

Science.gov (United States)

Hsu, Chun-Nan; Chang, Yu-Ming; Kuo, Cheng-Ju; Lin, Yu-Shi; Huang, Han-Shen; Chung, I-Fang

2008-07-01

Tagging gene and gene product mentions in scientific text is an important initial step of literature mining. In this article, we describe in detail our gene mention tagger participated in BioCreative 2 challenge and analyze what contributes to its good performance. Our tagger is based on the conditional random fields model (CRF), the most prevailing method for the gene mention tagging task in BioCreative 2. Our tagger is interesting because it accomplished the highest F-scores among CRF-based methods and second over all. Moreover, we obtained our results by mostly applying open source packages, making it easy to duplicate our results. We first describe in detail how we developed our CRF-based tagger. We designed a very high dimensional feature set that includes most of information that may be relevant. We trained bi-directional CRF models with the same set of features, one applies forward parsing and the other backward, and integrated two models based on the output scores and dictionary filtering. One of the most prominent factors that contributes to the good performance of our tagger is the integration of an additional backward parsing model. However, from the definition of CRF, it appears that a CRF model is symmetric and bi-directional parsing models will produce the same results. We show that due to different feature settings, a CRF model can be asymmetric and the feature setting for our tagger in BioCreative 2 not only produces different results but also gives backward parsing models slight but constant advantage over forward parsing model. To fully explore the potential of integrating bi-directional parsing models, we applied different asymmetric feature settings to generate many bi-directional parsing models and integrate them based on the output scores. Experimental results show that this integrated model can achieve even higher F-score solely based on the training corpus for gene mention tagging. Data sets, programs and an on-line service of our gene

High-speed fan-beam reconstruction using direct two-dimensional Fourier transform method

International Nuclear Information System (INIS)

Niki, Noboru; Mizutani, Toshio; Takahashi, Yoshizo; Inouye, Tamon.

1984-01-01

Since the first development of X-ray computer tomography (CT), various efforts have been made to obtain high quality of high-speed image. However, the development of high resolution CT and the ultra-high speed CT to be applied to hearts is still desired. The X-ray beam scanning method was already changed from the parallel beam system to the fan-beam system in order to greatly shorten the scanning time. Also, the filtered back projection (DFBP) method has been employed to directly processing fan-beam projection data as reconstruction method. Although the two-dimensional Fourier transform (TFT) method significantly faster than FBP method was proposed, it has not been sufficiently examined for fan-beam projection data. Thus, the ITFT method was investigated, which first executes rebinning algorithm to convert the fan-beam projection data to the parallel beam projection data, thereafter, uses two-dimensional Fourier transform. By this method, although high speed is expected, the reconstructed images might be degraded due to the adoption of rebinning algorithm. Therefore, the effect of the interpolation error of rebinning algorithm on the reconstructed images has been analyzed theoretically, and finally, the result of the employment of spline interpolation which allows the acquisition of high quality images with less errors has been shown by the numerical and visual evaluation based on simulation and actual data. Computation time was reduced to 1/15 for the image matrix of 512 and to 1/30 for doubled matrix. (Wakatsuki, Y.)

Degradation-mediated cellular traction directs stem cell fate in covalently crosslinked three-dimensional hydrogels

Science.gov (United States)

Khetan, Sudhir; Guvendiren, Murat; Legant, Wesley R.; Cohen, Daniel M.; Chen, Christopher S.; Burdick, Jason A.

2013-05-01

Although cell-matrix adhesive interactions are known to regulate stem cell differentiation, the underlying mechanisms, in particular for direct three-dimensional encapsulation within hydrogels, are poorly understood. Here, we demonstrate that in covalently crosslinked hyaluronic acid (HA) hydrogels, the differentiation of human mesenchymal stem cells (hMSCs) is directed by the generation of degradation-mediated cellular traction, independently of cell morphology or matrix mechanics. hMSCs within HA hydrogels of equivalent elastic moduli that permit (restrict) cell-mediated degradation exhibited high (low) degrees of cell spreading and high (low) tractions, and favoured osteogenesis (adipogenesis). Moreover, switching the permissive hydrogel to a restrictive state through delayed secondary crosslinking reduced further hydrogel degradation, suppressed traction, and caused a switch from osteogenesis to adipogenesis in the absence of changes to the extended cellular morphology. Furthermore, inhibiting tension-mediated signalling in the permissive environment mirrored the effects of delayed secondary crosslinking, whereas upregulating tension induced osteogenesis even in the restrictive environment.

Three-dimensional ICT reconstruction

International Nuclear Information System (INIS)

Zhang Aidong; Li Ju; Chen Fa; Sun Lingxia

2005-01-01

The three-dimensional ICT reconstruction method is the hot topic of recent ICT technology research. In the context, qualified visual three-dimensional ICT pictures are achieved through multi-piece two-dimensional images accumulation by, combining with thresholding method and linear interpolation. Different direction and different position images of the reconstructed pictures are got by rotation and interception respectively. The convenient and quick method is significantly instructive to more complicated three-dimensional reconstruction of ICT images. (authors)

Three-dimensional ICT reconstruction

International Nuclear Information System (INIS)

Zhang Aidong; Li Ju; Chen Fa; Sun Lingxia

2004-01-01

The three-dimensional ICT reconstruction method is the hot topic of recent ICT technology research. In the context qualified visual three-dimensional ICT pictures are achieved through multi-piece two-dimensional images accumulation by order, combining with thresholding method and linear interpolation. Different direction and different position images of the reconstructed pictures are got by rotation and interception respectively. The convenient and quick method is significantly instructive to more complicated three-dimensional reconstruction of ICT images. (authors)

BioJS DAGViewer: A reusable JavaScript component for displaying directed graphs.

Science.gov (United States)

Kalderimis, Alexis; Stepan, Radek; Sullivan, Julie; Lyne, Rachel; Lyne, Michael; Micklem, Gos

2014-01-01

The DAGViewer BioJS component is a reusable JavaScript component made available as part of the BioJS project and intended to be used to display graphs of structured data, with a particular emphasis on Directed Acyclic Graphs (DAGs). It enables users to embed representations of graphs of data, such as ontologies or phylogenetic trees, in hyper-text documents (HTML). This component is generic, since it is capable (given the appropriate configuration) of displaying any kind of data that is organised as a graph. The features of this component which are useful for examining and filtering large and complex graphs are described. http://github.com/alexkalderimis/dag-viewer-biojs; http://github.com/biojs/biojs; http://dx.doi.org/10.5281/zenodo.8303.

Two-dimensional characteristic polynomials in the direct calculation of optical phase sum and difference

International Nuclear Information System (INIS)

Miranda, M; Dorrio, B V; Blanco, J; Diz-Bugarin, J; Ribas, F

2011-01-01

Two-stage phase shifting algorithms make possible to directly recover the sum or the difference of the encoded optical phase of two different fringe patterns. These algorithms can be constructed, for example, by combining known phase shifting algorithms in a non-linear way. In this work two-stage phase shifting algorithms are linked to a two-dimensional characteristic polynomial to qualitatively analyse their behaviour against the main systematic error sources in an analysis protocol like that used for phase shifting algorithms. This tool enables us to understand the propagation of properties from precursor phase shifting algorithms to new evaluation algorithms that can be built from them.

Assessment of MARS for downcomer multi-dimensional thermal hydraulics during LBLOCA reflood using KAERI air-water direct vessel injection tests

Energy Technology Data Exchange (ETDEWEB)

Won-Jae, Lee; Kwi-Seok, Ha; Chul-Hwa, Song [Korea Atomic Energy Research Inst., Daejeon (Korea, Republic of)

2001-07-01

The MARS code has been assessed for the downcomer multi-dimensional thermal hydraulics during a large break loss-of-coolant accident (LBLOCA) reflood of Korean Next Generation Reactor (KNGR) that adopted an upper direct vessel injection (DVI) design. Direct DVI bypass and downcomer level sweep-out tests carried out at 1/50-scale air-water DVI test facility are simulated to examine the capability of MARS. Test conditions are selected such that they represent typical reflood conditions of KNGR, that is, DVI injection velocities of 1.0 {approx} 1.6 m/sec and air injection velocities of 18.0 {approx} 35.0 m/sec, for single and double DVI configurations. MARS calculation is first adjusted to the experimental DVI film distribution that largely affects air-water interaction in a scaled-down downcomer, then, the code is assessed for the selected test matrix. With some improvements of MARS thermal-hydraulic (T/H) models, it has been demonstrated that the MARS code is capable of simulating the direct DVI bypass and downcomer level sweep-out as well as the multi-dimensional thermal hydraulics in downcomer, where condensation effect is excluded. (authors)

A sparse grid based method for generative dimensionality reduction of high-dimensional data

Science.gov (United States)

Bohn, Bastian; Garcke, Jochen; Griebel, Michael

2016-03-01

Generative dimensionality reduction methods play an important role in machine learning applications because they construct an explicit mapping from a low-dimensional space to the high-dimensional data space. We discuss a general framework to describe generative dimensionality reduction methods, where the main focus lies on a regularized principal manifold learning variant. Since most generative dimensionality reduction algorithms exploit the representer theorem for reproducing kernel Hilbert spaces, their computational costs grow at least quadratically in the number n of data. Instead, we introduce a grid-based discretization approach which automatically scales just linearly in n. To circumvent the curse of dimensionality of full tensor product grids, we use the concept of sparse grids. Furthermore, in real-world applications, some embedding directions are usually more important than others and it is reasonable to refine the underlying discretization space only in these directions. To this end, we employ a dimension-adaptive algorithm which is based on the ANOVA (analysis of variance) decomposition of a function. In particular, the reconstruction error is used to measure the quality of an embedding. As an application, the study of large simulation data from an engineering application in the automotive industry (car crash simulation) is performed.

On acyclicity of games with cycles

DEFF Research Database (Denmark)

Andersson, Klas Olof Daniel; Hansen, Thomas Dueholm; Gurvich, Vladimir

2010-01-01

We study restricted improvement cycles (ri-cycles) in finite positional n-person games with perfect information modeled by directed graphs (di-graphs) that may contain directed cycles (di-cycles). We assume that all these di-cycles form one outcome c, for example, a draw. We obtain criteria...

Direct numerical simulation of the passive scalar field in a two-dimensional turbulent channel flow

International Nuclear Information System (INIS)

Kasagi, N.; Tomita, Y.; Kuroda, A.

1991-01-01

This paper reports on a direct numerical simulation (DNS) of the fully developed thermal field in a two-dimensional turbulent channel flow of air that was carried out. The iso-flux condition is imposed on the walls so that the local mean temperature linearly increases in the streamwise direction. The computation was executed on 1,589,248 grid points by using a spectral method. The statistics obtained include rms velocity and temperature fluctuations, Reynolds stresses, turbulent heat fluxes and other higher order correlations. They are compared mainly with the DNS data obtained by Kim and Moin (1987) and Kim (1987) in a higher Reynolds number flow with isothermal walls. Agreement between these two results is generally good. Each term in the budget equations of temperature variance, its dissipation rate and turbulent heat fluxes is also calculated in order to establish a data base of convective heat transfer for thermal turbulence modeling

Three-dimensional two-phase mass transport model for direct methanol fuel cells

International Nuclear Information System (INIS)

Yang, W.W.; Zhao, T.S.; Xu, C.

2007-01-01

A three-dimensional (3D) steady-state model for liquid feed direct methanol fuel cells (DMFC) is presented in this paper. This 3D mass transport model is formed by integrating five sub-models, including a modified drift-flux model for the anode flow field, a two-phase mass transport model for the porous anode, a single-phase model for the polymer electrolyte membrane, a two-phase mass transport model for the porous cathode, and a homogeneous mist-flow model for the cathode flow field. The two-phase mass transport models take account the effect of non-equilibrium evaporation/ condensation at the gas-liquid interface. A 3D computer code is then developed based on the integrated model. After being validated against the experimental data reported in the literature, the code was used to investigate numerically transport behaviors at the DMFC anode and their effects on cell performance

Direct Writing of Three-Dimensional Macroporous Photonic Crystals on Pressure-Responsive Shape Memory Polymers.

Science.gov (United States)

Fang, Yin; Ni, Yongliang; Leo, Sin-Yen; Wang, Bingchen; Basile, Vito; Taylor, Curtis; Jiang, Peng

2015-10-28

Here we report a single-step direct writing technology for making three-dimensional (3D) macroporous photonic crystal patterns on a new type of pressure-responsive shape memory polymer (SMP). This approach integrates two disparate fields that do not typically intersect: the well-established templating nanofabrication and shape memory materials. Periodic arrays of polymer macropores templated from self-assembled colloidal crystals are squeezed into disordered arrays in an unusual shape memory "cold" programming process. The recovery of the original macroporous photonic crystal lattices can be triggered by direct writing at ambient conditions using both macroscopic and nanoscopic tools, like a pencil or a nanoindenter. Interestingly, this shape memory disorder-order transition is reversible and the photonic crystal patterns can be erased and regenerated hundreds of times, promising the making of reconfigurable/rewritable nanooptical devices. Quantitative insights into the shape memory recovery of collapsed macropores induced by the lateral shear stresses in direct writing are gained through fundamental investigations on important process parameters, including the tip material, the critical pressure and writing speed for triggering the recovery of the deformed macropores, and the minimal feature size that can be directly written on the SMP membranes. Besides straightforward applications in photonic crystal devices, these smart mechanochromic SMPs that are sensitive to various mechanical stresses could render important technological applications ranging from chromogenic stress and impact sensors to rewritable high-density optical data storage media.

Continuity of the direct and inverse problems in one-dimensional scattering theory and numerical solution of the inverse problem

International Nuclear Information System (INIS)

Moura, C.A. de.

1976-09-01

We propose an algorithm for computing the potential V(x) associated to the one-dimensional Schroedinger operator E identical to - d 2 /dx 2 + V(x) -infinite < x< infinite from knowledge of the S.matrix, more exactly, of one of the reelection coefficients. The convergence of the algorithm is guaranteed by the stability results obtained for both the direct and inverse problems

Application of fast Fourier transforms to the direct solution of a class of two-dimensional separable elliptic equations on the sphere

Science.gov (United States)

Moorthi, Shrinivas; Higgins, R. W.

1993-01-01

An efficient, direct, second-order solver for the discrete solution of a class of two-dimensional separable elliptic equations on the sphere (which generally arise in implicit and semi-implicit atmospheric models) is presented. The method involves a Fourier transformation in longitude and a direct solution of the resulting coupled second-order finite-difference equations in latitude. The solver is made efficient by vectorizing over longitudinal wave-number and by using a vectorized fast Fourier transform routine. It is evaluated using a prescribed solution method and compared with a multigrid solver and the standard direct solver from FISHPAK.

Peretinoin, an Acyclic Retinoid, Inhibits Hepatitis B Virus Replication by Suppressing Sphingosine Metabolic Pathway In Vitro

Directory of Open Access Journals (Sweden)

Kazuhisa Murai

2018-01-01

Full Text Available Hepatocellular carcinoma (HCC frequently develops from hepatitis C virus (HCV and hepatitis B virus (HBV infection. We previously reported that peretinoin, an acyclic retinoid, inhibits HCV replication. This study aimed to examine the influence of peretinoin on the HBV lifecycle. HBV-DNA and covalently closed circular DNA (cccDNA were evaluated by a qPCR method in HepG2.2.15 cells. Peretinoin significantly reduced the levels of intracellular HBV-DNA, nuclear cccDNA, and HBV transcript at a concentration that did not induce cytotoxicity. Conversely, other retinoids, such as 9-cis, 13-cis retinoic acid (RA, and all-trans-retinoic acid (ATRA, had no effect or rather increased HBV replication. Mechanistically, although peretinoin increased the expression of HBV-related transcription factors, as observed for other retinoids, peretinoin enhanced the binding of histone deacetylase 1 (HDAC1 to cccDNA in the nucleus and negatively regulated HBV transcription. Moreover, peretinoin significantly inhibited the expression of SPHK1, a potential inhibitor of HDAC activity, and might be involved in hepatic inflammation, fibrosis, and HCC. SPHK1 overexpression in cells cancelled the inhibition of HBV replication induced by peretinoin. This indicates that peretinoin activates HDAC1 and thereby suppresses HBV replication by inhibiting the sphingosine metabolic pathway. Therefore, peretinoin may be a novel therapeutic agent for HBV replication and chemoprevention against HCC.

Ultrasound directed self-assembly of three-dimensional user-specified patterns of particles in a fluid medium

Science.gov (United States)

Prisbrey, M.; Greenhall, J.; Guevara Vasquez, F.; Raeymaekers, B.

2017-01-01

We use ultrasound directed self-assembly to organize particles dispersed in a fluid medium into a three-dimensional (3D) user-specified pattern. The technique employs ultrasound transducers that line the boundary of a fluid reservoir to create a standing ultrasound wave field. The acoustic radiation force associated with the wave field drives particles dispersed in the fluid medium into organized patterns, assuming that the particles are much smaller than the wavelength and do not interact with each other. We have theoretically derived a direct solution method to calculate the ultrasound transducer operating parameters that are required to assemble a user-specified 3D pattern of particles in a fluid reservoir of arbitrary geometry. We formulate the direct solution method as a constrained optimization problem that reduces to eigendecomposition. We experimentally validate the solution method by assembling 3D patterns of carbon nanoparticles in a water reservoir and observe good quantitative agreement between theory and experiment. Additionally, we demonstrate the versatility of the solution method by simulating ultrasound directed self-assembly of complex 3D patterns of particles. The method works for any 3D simple, closed fluid reservoir geometry in combination with any arrangement of ultrasound transducers and enables employing ultrasound directed self-assembly in a myriad of engineering applications, including biomedical and materials fabrication processes.

TMCC: a transient three-dimensional neutron transport code by the direct simulation method - 222

International Nuclear Information System (INIS)

Shen, H.; Li, Z.; Wang, K.; Yu, G.

2010-01-01

A direct simulation method (DSM) is applied to solve the transient three-dimensional neutron transport problems. DSM is based on the Monte Carlo method, and can be considered as an application of the Monte Carlo method in the specific type of problems. In this work, the transient neutronics problem is solved by simulating the dynamic behaviors of neutrons and precursors of delayed neutrons during the transient process. DSM gets rid of various approximations which are always necessary to other methods, so it is precise and flexible in the requirement of geometric configurations, material compositions and energy spectrum. In this paper, the theory of DSM is introduced first, and the numerical results obtained with the new transient analysis code, named TMCC (Transient Monte Carlo Code), are presented. (authors)

Independencies Induced from a Graphical Markov Model After Marginalization and Conditioning: The R Package ggm

Directory of Open Access Journals (Sweden)

Giovanni M. Marchetti

2006-02-01

Full Text Available We describe some functions in the R package ggm to derive from a given Markov model, represented by a directed acyclic graph, different types of graphs induced after marginalizing over and conditioning on some of the variables. The package has a few basic functions that find the essential graph, the induced concentration and covariance graphs, and several types of chain graphs implied by the directed acyclic graph (DAG after grouping and reordering the variables. These functions can be useful to explore the impact of latent variables or of selection effects on a chosen data generating model.

Direct lifts of coupled cell networks

Science.gov (United States)

Dias, A. P. S.; Moreira, C. S.

2018-04-01

In networks of dynamical systems, there are spaces defined in terms of equalities of cell coordinates which are flow-invariant under any dynamical system that has a form consistent with the given underlying network structure—the network synchrony subspaces. Given a network and one of its synchrony subspaces, any system with a form consistent with the network, restricted to the synchrony subspace, defines a new system which is consistent with a smaller network, called the quotient network of the original network by the synchrony subspace. Moreover, any system associated with the quotient can be interpreted as the restriction to the synchrony subspace of a system associated with the original network. We call the larger network a lift of the smaller network, and a lift can be interpreted as a result of the cellular splitting of the smaller network. In this paper, we address the question of the uniqueness in this lifting process in terms of the networks’ topologies. A lift G of a given network Q is said to be direct when there are no intermediate lifts of Q between them. We provide necessary and sufficient conditions for a lift of a general network to be direct. Our results characterize direct lifts using the subnetworks of all splitting cells of Q and of all split cells of G. We show that G is a direct lift of Q if and only if either the split subnetwork is a direct lift or consists of two copies of the splitting subnetwork. These results are then applied to the class of regular uniform networks and to the special classes of ring networks and acyclic networks. We also illustrate that one of the applications of our results is to the lifting bifurcation problem.

Mediation misgivings: ambiguous clinical and public health interpretations of natural direct and indirect effects.

Science.gov (United States)

Naimi, Ashley I; Kaufman, Jay S; MacLehose, Richard F

2014-10-01

Recent methodological innovation is giving rise to an increasing number of applied papers in medical and epidemiological journals in which natural direct and indirect effects are estimated. However, there is a longstanding debate on whether such effects are relevant targets of inference in population health. In light of the repeated calls for a more pragmatic and consequential epidemiology, we review three issues often raised in this debate: (i) the use of composite cross-world counterfactuals and the need for cross-world independence assumptions; (ii) interventional vs non-interventional identifiability; and (iii) the interpretational ambiguity of natural direct and indirect effect estimates. We use potential outcomes notation and directed acyclic graphs to explain 'cross-world' assumptions, illustrate implications of this assumption via regression models and discuss ensuing issues of interpretation. We argue that the debate on the relevance of natural direct and indirect effects rests on whether one takes as a target of inference the mathematical object per se, or the change in the world that the mathematical object represents. We further note that public health questions may be better served by estimating controlled direct effects. © The Author 2014; all rights reserved. Published by Oxford University Press on behalf of the International Epidemiological Association.

Three dimensional graphene transistor for ultra-sensitive pH sensing directly in biological media.

Science.gov (United States)

Ameri, Shideh Kabiri; Singh, Pramod K; Sonkusale, Sameer R

2016-08-31

In this work, pH sensing directly in biological media using three dimensional liquid gated graphene transistors is presented. The sensor is made of suspended network of graphene coated all around with thin layer of hafnium oxide (HfO2), showing high sensitivity and sensing beyond the Debye-screening limit. The performance of the pH sensor is validated by measuring the pH of isotonic buffered, Dulbecco's phosphate buffered saline (DPBS) solution, and of blood serum derived from Sprague-Dawley rat. The pH sensor shows high sensitivity of 71 ± 7 mV/pH even in high ionic strength media with molarities as high as 289 ± 1 mM. High sensitivity of this device is owing to suspension of three dimensional graphene in electrolyte which provides all around liquid gating of graphene, leading to higher electrostatic coupling efficiency of electrolyte to the channel and higher gating control of transistor channel by ions in the electrolyte. Coating graphene with hafnium oxide film (HfO2) provides binding sites for hydrogen ions, which results in higher sensitivity and sensing beyond the Debye-screening limit. The 3D graphene transistor offers the possibility of real-time pH measurement in biological media without the need for desaltation or sample preparation. Copyright © 2016 Elsevier B.V. All rights reserved.

Alternating-direction implicit numerical solution of the time-dependent, three-dimensional, single fluid, resistive magnetohydrodynamic equations

Energy Technology Data Exchange (ETDEWEB)

Finan, C.H. III

1980-12-01

Resistive magnetohydrodynamics (MHD) is described by a set of eight coupled, nonlinear, three-dimensional, time-dependent, partial differential equations. A computer code, IMP (Implicit MHD Program), has been developed to solve these equations numerically by the method of finite differences on an Eulerian mesh. In this model, the equations are expressed in orthogonal curvilinear coordinates, making the code applicable to a variety of coordinate systems. The Douglas-Gunn algorithm for Alternating-Direction Implicit (ADI) temporal advancement is used to avoid the limitations in timestep size imposed by explicit methods. The equations are solved simultaneously to avoid syncronization errors.

X-ray imaging device for one-dimensional and two-dimensional radioscopy

International Nuclear Information System (INIS)

1978-01-01

The X-ray imaging device for the selectable one-dimensional or two-dimensional pictures of objects illuminated by X-rays, comprising an X-ray source, an X-ray screen, and an opto-electrical picture development device placed behind the screen, is characterized by an anamorphotic optical system, which is positioned with a one-dimensional illumination between the X-ray screen and the opto-electrical device and that a two-dimensional illumination will be developed, and that in view of the lens system which forms part of the opto-electrical device, there is placed an X-ray screen in a specified beam direction so that a magnified image may be formed by equalisation of the distance between the X-ray screen and the lens system. (G.C.)

Two-dimensional metamaterial optics

International Nuclear Information System (INIS)

Smolyaninov, I I

2010-01-01

While three-dimensional photonic metamaterials are difficult to fabricate, many new concepts and ideas in the metamaterial optics can be realized in two spatial dimensions using planar optics of surface plasmon polaritons. In this paper we review recent progress in this direction. Two-dimensional photonic crystals, hyperbolic metamaterials, and plasmonic focusing devices are demonstrated and used in novel microscopy and waveguiding schemes

Amperometric carbohydrate antigen 19-9 immunosensor based on three dimensional ordered macroporous magnetic Au film coupling direct electrochemistry of horseradish peroxidase

Energy Technology Data Exchange (ETDEWEB)

Zhang, Qi [College of Sciences, Nanjing Tech University, Nanjing 211816 (China); Chen, Xiaojun, E-mail: chenxj_njut@126.com [College of Sciences, Nanjing Tech University, Nanjing 211816 (China); State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 210009 (China); Tang, Yin [Zhangjiagang Hospital of Traditional Chinese Medicine, Zhangjiagang 215600 (China); Ge, Lingna; Guo, Buhua [College of Sciences, Nanjing Tech University, Nanjing 211816 (China); Yao, Cheng, E-mail: yaochengnjut@163.com [College of Sciences, Nanjing Tech University, Nanjing 211816 (China)

2014-03-01

Highlights: • Three dimensional ordered macroporous magnetic electrode was newly used in electrochemical immunosensor. • The large surface area of macroporous magnetic electrode could improve the immobilized amount of antibody. • Au nanoparticles functionalized SBA-15 was used to immobilize enzyme labeled Ab₂ and enzyme. • Macroporous magnetic electrode and Au nanoparticles composite facilitated the direct electron transfer of enzyme. • The immunoassay avoided adding electron transfer mediator, simplifying the procedure. Abstract: A sandwich-type electrochemical immunosensor for the detection of carbohydrate antigen 19-9 (CA 19-9) antigen based on the immobilization of primary antibody (Ab₁) on three dimensional ordered macroporous magnetic (3DOMM) electrode, and the direct electrochemistry of horseradish peroxidase (HRP) that was used as both the label of secondary antibody (Ab₂) and the blocking reagent. The 3DOMM electrode was fabricated by introducing core–shell Au–SiO₂@Fe₃O₄ nanospheres onto the surface of three dimensional ordered macroporous (3DOM) Au electrode via the application of an external magnet. Au nanoparticles functionalized SBA-15 (Au@SBA-15) was conjugated to the HRP labeled secondary antibody (HRP-Ab₂) through the Au–SH or Au–NH₃⁺ interaction, and HRP was also used as the block reagent. The formation of antigen–antibody complex made the combination of Au@SBA-15 and 3DOMM exhibit remarkable synergistic effects for accelerating direct electron transfer (DET) between HRP and the electrode. Under the optimal conditions, the DET current signal increased proportionally to CA 19-9 concentration in the range of 0.05 to 15.65 U mL⁻¹ with a detection limit of 0.01 U mL⁻¹. Moreover, the immunosensor showed high selectivity, good stability, satisfactory reproducibility and regeneration. Importantly, the developed method was used to assay clinical serum specimens, achieving a good relation with those obtained from

Direct Observation of Energy Detrapping in LH1-RC Complex by Two-Dimensional Electronic Spectroscopy.

Science.gov (United States)

Ma, Fei; Yu, Long-Jiang; Hendrikx, Ruud; Wang-Otomo, Zheng-Yu; van Grondelle, Rienk

2017-01-18

The purple bacterial core light harvesting antenna-reaction center (LH1-RC) complex is the simplest system able to achieve the entire primary function of photosynthesis. During the past decade, a variety of photosynthetic proteins were studied by a powerful technique, two-dimensional electronic spectroscopy (2DES). However, little attention has been paid to LH1-RC, although its reversible uphill energy transfer, trapping, and backward detrapping processes, represent a crucial step in the early photosynthetic reaction dynamics. Thus, in this work, we employed 2DES to study two LH1-RC complexes of Thermochromatium (Tch.) tepidum. By direct observation of detrapping, the complex reversible process was clearly identified and an overall scheme of the excitation evolution in LH1-RC was obtained.

The resolution of acyclic P-stereogenic phosphine oxides via the formation of diastereomeric complexes: A case study on ethyl-(2-methylphenyl)-phenylphosphine oxide.

Science.gov (United States)

Bagi, Péter; Varga, Bence; Szilágyi, András; Karaghiosoff, Konstantin; Czugler, Mátyás; Fogassy, Elemér; Keglevich, György

2018-04-01

As an example of acyclic P-chiral phosphine oxides, the resolution of ethyl-(2-methylphenyl)-phenylphosphine oxide was elaborated with TADDOL derivatives, or with calcium salts of the tartaric acid derivatives. Besides the study on the resolving agents, several purification methods were developed in order to prepare enantiopure ethyl-(2-methylphenyl)-phenylphosphine oxide. It was found that the title phosphine oxide is a racemic crystal-forming compound, and the recrystallization of the enantiomeric mixtures could be used for the preparation of pure enantiomers. According to our best method, the (R)-ethyl-(2-methylphenyl)-phenylphosphine oxide could be obtained with an enantiomeric excess of 99% and in a yield of 47%. Complete racemization of the enantiomerically enriched phosphine oxide could be accomplished via the formation of a chlorophosphonium salt. Characterization of the crystal structures of the enantiopure phosphine oxide was complemented with that of the diastereomeric intermediate. X-ray analysis revealed the main nonbonding interactions responsible for enantiomeric recognition. © 2018 Wiley Periodicals, Inc.

Isolation and Characterization of an Acyclic Isoprenoid from Semecarpus anacardium Linn. and its Antibacterial Potential in vitro - Antimicrobial Activity of Semecarpus anacardium Linn. Seeds -

Directory of Open Access Journals (Sweden)

Ayyakkannu Purushothaman

2017-06-01

Full Text Available Objectives: Semecarpus anacardium Linn. is a plant well-known for its antimicrobial, antidiabetic and anti-arthritic properties in the Ayurvedic and Siddha system of medicine. This has prompted the screening of this plant for antibacterial activity. The main aims of this study were to isolate compounds from the plant’s seeds and to evaluate their antibacterial effects on clinical bacterial test strains. Methods: The n-butanolic concentrate of the seed extract was subjected to thin layer chromatography (TLC and repeated silica gel column chromatography followed by elution with various solvents. The compound was identified based on observed spectral (IR, 1H NMR, 13C NMR and high-resolution mass spectrometry data. The well diffusion method was employed to evaluate the antibacterial activities of the isolated acyclic isoprenoid compound (final concentration: 5 - 15 μg/mL on four test bacterial strains, namely, Staphylococcus aureus (MTCC 96, Bacillus cereus

One-dimensional hybrid-direct kinetic simulation of the discharge plasma in a Hall thruster

International Nuclear Information System (INIS)

Hara, Kentaro; Boyd, Iain D.; Kolobov, Vladimir I.

2012-01-01

In order to model the non-equilibrium plasma within the discharge region of a Hall thruster, the velocity distribution functions (VDFs) must be obtained accurately. A direct kinetic (DK) simulation method that directly solves the plasma Boltzmann equation can achieve better resolution of VDFs in comparison to particle simulations, such as the particle-in-cell (PIC) method that inherently include statistical noise. In this paper, a one-dimensional hybrid-DK simulation, which uses a DK simulation for heavy species and a fluid model for electrons, is developed and compared to a hybrid-PIC simulation. Time-averaged results obtained from the hybrid-DK simulation are in good agreement with hybrid-PIC results and experimental data. It is shown from a comparison of using a kinetic simulation and solving the continuity equation that modeling of the neutral atoms plays an important role for simulations of the Hall thruster discharge plasma. In addition, low and high frequency plasma oscillations are observed. Although the kinetic nature of electrons is not resolved due to the use of a fluid model, the hybrid-DK model provides spatially and temporally well-resolved plasma properties and an improved resolution of VDFs for heavy species with less statistical noise in comparison to the hybrid-PIC method.

Development of a two-dimensional simulation code (koad) including atomic processes for beam direct energy conversion

International Nuclear Information System (INIS)

Yamamoto, Y.; Yoshikawa, K.; Hattori, Y.

1987-01-01

A two-dimensional simulation code for the beam direct energy conversion called KVAD (Kyoto University Advanced DART) including various loss mechanisms has been developed, and shown excellent agreement with the authors' experiments using the He + beams. The beam direct energy converter (BDC) is the device to recover the kinetic energy of unneutralized ions in the neutral beam injection (NBI) system directly into electricity. The BDC is very important and essential not only to the improvements of NBI system efficiency, but also to the relaxation of high heat flux problems on the beam dump with increase of injection energies. So far no simulation code could have successfully predicted BDC experimental results. The KUAD code applies, an optimized algorithm for vector processing, the finite element method (FEM) for potential calculation, and a semi-automatic method for spatial segmentations. Since particle trajectories in the KVAD code are analytically solved, very high speed tracings of the particle could be achieved by introducing an adjacent element matrix to identify the neighboring triangle elements and electrodes. Ion space charges are also analytically calculated by the Cloud in Cell (CIC) method, as well as electron space charges. Power losses due to atomic processes can be also evaluated in the KUAD code

Three-dimensional analysis of craniofacial bones using three-dimensional computer tomography

Energy Technology Data Exchange (ETDEWEB)

Ono, Ichiro; Ohura, Takehiko; Kimura, Chu (Hokkaido Univ., Sapporo (Japan). School of Medicine) (and others)

1989-08-01

Three-dimensional computer tomography (3DCT) was performed in patients with various diseases to visualize stereoscopically the deformity of the craniofacial bones. The data obtained were analyzed by the 3DCT analyzing system. A new coordinate system was established using the median sagittal plane of the face (a plane passing through sella, nasion and basion) on the three-dimensional image. Three-dimensional profilograms were prepared for detailed analysis of the deformation of craniofacial bones for cleft lip and palate, mandibular prognathia and hemifacial microsomia. For patients, asymmetry in the frontal view and twist-formed complicated deformities were observed, as well as deformity of profiles in the anteroposterior and up-and-down directions. A newly developed technique allows three-dimensional visualization of changes in craniofacial deformity. It would aid in determining surgical strategy, including crani-facial surgery and maxillo-facial surgery, and in evaluating surgical outcome. (N.K.).

Three-dimensional analysis of craniofacial bones using three-dimensional computer tomography

International Nuclear Information System (INIS)

Ono, Ichiro; Ohura, Takehiko; Kimura, Chu

1989-01-01

Three-dimensional computer tomography (3DCT) was performed in patients with various diseases to visualize stereoscopically the deformity of the craniofacial bones. The data obtained were analyzed by the 3DCT analyzing system. A new coordinate system was established using the median sagittal plane of the face (a plane passing through sella, nasion and basion) on the three-dimensional image. Three-dimensional profilograms were prepared for detailed analysis of the deformation of craniofacial bones for cleft lip and palate, mandibular prognathia and hemifacial microsomia. For patients, asymmetry in the frontal view and twist-formed complicated deformities were observed, as well as deformity of profiles in the anteroposterior and up-and-down directions. A newly developed technique allows three-dimensional visualization of changes in craniofacial deformity. It would aid in determining surgical strategy, including crani-facial surgery and maxillo-facial surgery, and in evaluating surgical outcome. (N.K.)

Direct Manipulation in Virtual Reality

Science.gov (United States)

Bryson, Steve

2003-01-01

Virtual Reality interfaces offer several advantages for scientific visualization such as the ability to perceive three-dimensional data structures in a natural way. The focus of this chapter is direct manipulation, the ability for a user in virtual reality to control objects in the virtual environment in a direct and natural way, much as objects are manipulated in the real world. Direct manipulation provides many advantages for the exploration of complex, multi-dimensional data sets, by allowing the investigator the ability to intuitively explore the data environment. Because direct manipulation is essentially a control interface, it is better suited for the exploration and analysis of a data set than for the publishing or communication of features found in that data set. Thus direct manipulation is most relevant to the analysis of complex data that fills a volume of three-dimensional space, such as a fluid flow data set. Direct manipulation allows the intuitive exploration of that data, which facilitates the discovery of data features that would be difficult to find using more conventional visualization methods. Using a direct manipulation interface in virtual reality, an investigator can, for example, move a data probe about in space, watching the results and getting a sense of how the data varies within its spatial volume.

New Three-Dimensional Porous Electrode Concept: Vertically-Aligned Carbon Nanotubes Directly Grown on Embroidered Copper Structures.

Science.gov (United States)

Aguiló-Aguayo, Noemí; Amade, Roger; Hussain, Shahzad; Bertran, Enric; Bechtold, Thomas

2017-12-11

New three-dimensional (3D) porous electrode concepts are required to overcome limitations in Li-ion batteries in terms of morphology (e.g., shapes, dimensions), mechanical stability (e.g., flexibility, high electroactive mass loadings), and electrochemical performance (e.g., low volumetric energy densities and rate capabilities). Here a new electrode concept is introduced based on the direct growth of vertically-aligned carbon nanotubes (VA-CNTs) on embroidered Cu current collectors. The direct growth of VA-CNTs was achieved by plasma-enhanced chemical vapor deposition (PECVD), and there was no application of any post-treatment or cleaning procedure. The electrochemical behavior of the as-grown VA-CNTs was analyzed by charge/discharge cycles at different specific currents and with electrochemical impedance spectroscopy (EIS) measurements. The results were compared with values found in the literature. The as-grown VA-CNTs exhibit higher specific capacities than graphite and pristine VA-CNTs found in the literature. This together with the possibilities that the Cu embroidered structures offer in terms of specific surface area, total surface area, and designs provide a breakthrough in new 3D electrode concepts.

Investigation on the Yarn Squeezing Effect of Three Dimensional Full Five Directional Braided Composites

Science.gov (United States)

Hu, Long; Tao, Guoquan; Liu, Zhenguo; Wang, Yibo; Ya, Jixuan

2018-04-01

The influence of yarn squeezing effect on the geometric morphology and mechanical property of the three dimensional full five directional (3DF5D) braided composites is explored. Spatial path and cross-section shape of the yarns in the braided structure are characterized based on the micro computed tomography (micro CT) scanning images. The yarn distortion due to the squeezing effect is discussed and mathematical morphology of the yarn geometry is established. A new repeated unit cell (RUC) model of 3DF5D braided composites considering yarn squeezing effect is developed. Based on this model, mechanical properties of 3DF5D braided composites are analyzed. Good agreement is obtained between the predicted and experiment results. Moreover, the stress distribution of the new RUC model are compared with original RUC model, showing that the squeezing effect significantly increases the stress concentration level of the axial yarns.

Understanding effects of matrix protease and matrix organization on directional persistence and translational speed in three-dimensional cell migration.

Science.gov (United States)

Zaman, Muhammad H; Matsudaira, Paul; Lauffenburger, Douglas A

2007-01-01

Recent studies have shown significant differences in migration mechanisms between two- and three-dimensional environments. While experiments have suggested a strong dependence of in vivo migration on both structure and proteolytic activity, the underlying biophysics of such dependence has not been studied adequately. In addition, the existing models of persistent random walk migration are primarily based on two-dimensional movement and do not account for the effect of proteolysis or matrix inhomogeneity. Using lattice Monte Carlo methods, we present a model to study the role of matrix metallo-proteases (MMPs) on directional persistence and speed. The simulations account for a given cell's ability to deform as well as to digest the matrix as the cell moves in three dimensions. Our results show a bimodal dependence of speed and persistence on matrix pore size and suggest high sensitivity on MMP activity, which is in very good agreement with experimental studies carried out in 3D matrices.

Three-dimensional graphene as gas diffusion layer for micro direct methanol fuel cell

Science.gov (United States)

Zhu, Yingli; Zhang, Xiaojian; Li, Jianyu; Qi, Gary

2018-05-01

The gas diffusion layer (GDL), as an important structure of the membrane electrode assembly (MEA) of the direct methanol fuel cell (DMFC), provides a support layer for the catalyst and the fuel and the product channel. Traditionally, the material of GDL is generally carbon paper (CP). In this paper, a new material, namely three-dimensional graphene (3DG) is used as GDL for micro DMFC. The experimental results reveal that the performance of the DMFC has been improved significantly by application of 3DG. The peak powers increase from 25 mW to 31.2 mW and 32 mW by using 3DG as the anode and cathode GDL instead of CP, respectively. The reason may be the decrease of charge and mass transfer resistance of the cell. This means that the unique 3D porous architecture of the 3DG can provide lower contact resistance and sufficient fuel diffusion paths. The output performance of the cell will be further improved when porous metal current collectors is used.

Direct Reconstruction of Two-Dimensional Currents in Thin Films from Magnetic-Field Measurements

Science.gov (United States)

Meltzer, Alexander Y.; Levin, Eitan; Zeldov, Eli

2017-12-01

An accurate determination of microscopic transport and magnetization currents is of central importance for the study of the electric properties of low-dimensional materials and interfaces, of superconducting thin films, and of electronic devices. Current distribution is usually derived from the measurement of the perpendicular component of the magnetic field above the surface of the sample, followed by numerical inversion of the Biot-Savart law. The inversion is commonly obtained by deriving the current stream function g , which is then differentiated in order to obtain the current distribution. However, this two-step procedure requires filtering at each step and, as a result, oversmooths the solution. To avoid this oversmoothing, we develop a direct procedure for inversion of the magnetic field that avoids use of the stream function. This approach provides enhanced accuracy of current reconstruction over a wide range of noise levels. We further introduce a reflection procedure that allows for the reconstruction of currents that cross the boundaries of the measurement window. The effectiveness of our approach is demonstrated by several numerical examples.

Graph Grammar-Based Multi-Frontal Parallel Direct Solver for Two-Dimensional Isogeometric Analysis

KAUST Repository

Kuźnik, Krzysztof

2012-06-02

This paper introduces the graph grammar based model for developing multi-thread multi-frontal parallel direct solver for two dimensional isogeometric finite element method. Execution of the solver algorithm has been expressed as the sequence of graph grammar productions. At the beginning productions construct the elimination tree with leaves corresponding to finite elements. Following sequence of graph grammar productions generates element frontal matri-ces at leaf nodes, merges matrices at parent nodes and eliminates rows corresponding to fully assembled degrees of freedom. Finally, there are graph grammar productions responsible for root problem solution and recursive backward substitutions. Expressing the solver algorithm by graph grammar productions allows us to explore the concurrency of the algorithm. The graph grammar productions are grouped into sets of independent tasks that can be executed concurrently. The resulting concurrent multi-frontal solver algorithm is implemented and tested on NVIDIA GPU, providing O(NlogN) execution time complexity where N is the number of degrees of freedom. We have confirmed this complexity by solving up to 1 million of degrees of freedom with 448 cores GPU.

A method for estimating the orientation of a directional sound source from source directivity and multi-microphone recordings: principles and application

DEFF Research Database (Denmark)

Guarato, Francesco; Jakobsen, Lasse; Vanderelst, Dieter

2011-01-01

Taking into account directivity of real sound sources makes it possible to try solving an interesting and biologically relevant problem: estimating the orientation in three-dimensional space of a directional sound source. The source, of known directivity, produces a broadband signal (in the ultra......Taking into account directivity of real sound sources makes it possible to try solving an interesting and biologically relevant problem: estimating the orientation in three-dimensional space of a directional sound source. The source, of known directivity, produces a broadband signal (in...

Three-dimensional biomedical imaging

International Nuclear Information System (INIS)

Robb, R.A.

1985-01-01

Scientists in biomedical imaging provide researchers, physicians, and academicians with an understanding of the fundamental theories and practical applications of three-dimensional biomedical imaging methodologies. Succinct descriptions of each imaging modality are supported by numerous diagrams and illustrations which clarify important concepts and demonstrate system performance in a variety of applications. Comparison of the different functional attributes, relative advantages and limitations, complementary capabilities, and future directions of three-dimensional biomedical imaging modalities are given. Volume 1: Introductions to Three-Dimensional Biomedical Imaging Photoelectronic-Digital Imaging for Diagnostic Radiology. X-Ray Computed Tomography - Basic Principles. X-Ray Computed Tomography - Implementation and Applications. X-Ray Computed Tomography: Advanced Systems and Applications in Biomedical Research and Diagnosis. Volume II: Single Photon Emission Computed Tomography. Position Emission Tomography (PET). Computerized Ultrasound Tomography. Fundamentals of NMR Imaging. Display of Multi-Dimensional Biomedical Image Information. Summary and Prognostications

A method for the direct measurement of electronic site populations in a molecular aggregate using two-dimensional electronic-vibrational spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Lewis, Nicholas H. C.; Dong, Hui; Oliver, Thomas A. A.; Fleming, Graham R., E-mail: grfleming@lbl.gov [Department of Chemistry, University of California, Berkeley, California 94720 (United States); Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Kavli Energy Nanosciences Institute at Berkeley, Berkeley, California 94720 (United States)

2015-09-28

Two dimensional electronic spectroscopy has proved to be a valuable experimental technique to reveal electronic excitation dynamics in photosynthetic pigment-protein complexes, nanoscale semiconductors, organic photovoltaic materials, and many other types of systems. It does not, however, provide direct information concerning the spatial structure and dynamics of excitons. 2D infrared spectroscopy has become a widely used tool for studying structural dynamics but is incapable of directly providing information concerning electronic excited states. 2D electronic-vibrational (2DEV) spectroscopy provides a link between these domains, directly connecting the electronic excitation with the vibrational structure of the system under study. In this work, we derive response functions for the 2DEV spectrum of a molecular dimer and propose a method by which 2DEV spectra could be used to directly measure the electronic site populations as a function of time following the initial electronic excitation. We present results from the response function simulations which show that our proposed approach is substantially valid. This method provides, to our knowledge, the first direct experimental method for measuring the electronic excited state dynamics in the spatial domain, on the molecular scale.

Analysis of green kiwi fruit (Actinidia deliciosa cv. Hayward) proteinases by two-dimensional zymography and direct identification of zymographic spots by mass spectrometry.

Science.gov (United States)

Larocca, Marilena; Rossano, Rocco; Riccio, Paolo

2010-11-01

Proteinases present in kiwi fruits are potentially allergenic enzymes belonging to the papain family of cysteine proteinases. Actinidin is a prominent kiwi enzyme. The study of kiwi proteinases is important for the follow-up of fruit maturation, a deeper insight in the allergenic properties of individual proteins, and the application of kiwi proteinases for meat tenderisation and other industrial purposes. Kiwi crude extracts were analysed by two-dimensional zymography on gelatin-containing gels. The digestion by the reactivated proteolytic enzymes after electrophoresis resulted in insights into kiwi proteinases. A mixture of several enzyme isotypes with the same pI but different molecular mass was observed. Clear spots, corresponding to the proteolytic activities, were excised, digested with trypsin, and submitted to MALDI-ToF mass spectrometry for protein identification. The most representative enzyme was actinidin. The innovative achievements of the present study are the: (1) two-dimensional zymographic map of kiwi gelatinases without the need for extensive purification; and (2) direct identification of proteinase isotypes by means of direct MALDI-ToF MS analysis of the zymographic spots. 2010 Society of Chemical Industry

Three-dimensional reciprocal space x-ray coherent scattering tomography of two-dimensional object.

Science.gov (United States)

Zhu, Zheyuan; Pang, Shuo

2018-04-01

X-ray coherent scattering tomography is a powerful tool in discriminating biological tissues and bio-compatible materials. Conventional x-ray scattering tomography framework can only resolve isotropic scattering profile under the assumption that the material is amorphous or in powder form, which is not true especially for biological samples with orientation-dependent structure. Previous tomography schemes based on x-ray coherent scattering failed to preserve the scattering pattern from samples with preferred orientations, or required elaborated data acquisition scheme, which could limit its application in practical settings. Here, we demonstrate a simple imaging modality to preserve the anisotropic scattering signal in three-dimensional reciprocal (momentum transfer) space of a two-dimensional sample layer. By incorporating detector movement along the direction of x-ray beam, combined with a tomographic data acquisition scheme, we match the five dimensions of the measurements with the five dimensions (three in momentum transfer domain, and two in spatial domain) of the object. We employed a collimated pencil beam of a table-top copper-anode x-ray tube, along with a panel detector to investigate the feasibility of our method. We have demonstrated x-ray coherent scattering tomographic imaging at a spatial resolution ~2 mm and momentum transfer resolution 0.01 Å -1 for the rotation-invariant scattering direction. For any arbitrary, non-rotation-invariant direction, the same spatial and momentum transfer resolution can be achieved based on the spatial information from the rotation-invariant direction. The reconstructed scattering profile of each pixel from the experiment is consistent with the x-ray diffraction profile of each material. The three-dimensional scattering pattern recovered from the measurement reveals the partially ordered molecular structure of Teflon wrap in our sample. We extend the applicability of conventional x-ray coherent scattering tomography to

Synthesis and Characterization of Acyclic and Cyclic Azabridged Ligands Incorporating 2,2'-Bipyridine Subunits and Their Complexes With Copper(II, Cobalt(II, and Nickel(II

Directory of Open Access Journals (Sweden)

Andrea Pappalardo

2003-07-01

Full Text Available The synthesis of a series of N,N'-disubstituted acyclic (AL and cyclic (CL aza-bridged ligands incorporating 2,2-pipryidine subunits is described. 1H-NMR and IR spectral data support the proposed ligand structures. Dynamic 1H-NMR studies on diurea and diamide derivatives point to the presence of slowly interconverting conformers on the 1H-NMR time-scale, owing to N−H···N hydrogen bonding and/or a restricted rotation around the amide bonds. The ligands synthesized form 1:1 complexes with divalent transition metal ions. Upon complexation, bis-ester derivatives AL5 and CL5 undergo a metal-induced hydrolysis of the ester groups to carboxyl functions, which act as additional binding sites for the metal ion, as well as hydrogen-bonding donor-acceptor binding site to produce dimeric complexes.

New Three-Dimensional Porous Electrode Concept: Vertically-Aligned Carbon Nanotubes Directly Grown on Embroidered Copper Structures

Directory of Open Access Journals (Sweden)

Noemí Aguiló-Aguayo

2017-12-01

Full Text Available New three-dimensional (3D porous electrode concepts are required to overcome limitations in Li-ion batteries in terms of morphology (e.g., shapes, dimensions, mechanical stability (e.g., flexibility, high electroactive mass loadings, and electrochemical performance (e.g., low volumetric energy densities and rate capabilities. Here a new electrode concept is introduced based on the direct growth of vertically-aligned carbon nanotubes (VA-CNTs on embroidered Cu current collectors. The direct growth of VA-CNTs was achieved by plasma-enhanced chemical vapor deposition (PECVD, and there was no application of any post-treatment or cleaning procedure. The electrochemical behavior of the as-grown VA-CNTs was analyzed by charge/discharge cycles at different specific currents and with electrochemical impedance spectroscopy (EIS measurements. The results were compared with values found in the literature. The as-grown VA-CNTs exhibit higher specific capacities than graphite and pristine VA-CNTs found in the literature. This together with the possibilities that the Cu embroidered structures offer in terms of specific surface area, total surface area, and designs provide a breakthrough in new 3D electrode concepts.

Theory and design of compact hybrid microphone arrays on two-dimensional planes for three-dimensional soundfield analysis.

Science.gov (United States)

Chen, Hanchi; Abhayapala, Thushara D; Zhang, Wen

2015-11-01

Soundfield analysis based on spherical harmonic decomposition has been widely used in various applications; however, a drawback is the three-dimensional geometry of the microphone arrays. In this paper, a method to design two-dimensional planar microphone arrays that are capable of capturing three-dimensional (3D) spatial soundfields is proposed. Through the utilization of both omni-directional and first order microphones, the proposed microphone array is capable of measuring soundfield components that are undetectable to conventional planar omni-directional microphone arrays, thus providing the same functionality as 3D arrays designed for the same purpose. Simulations show that the accuracy of the planar microphone array is comparable to traditional spherical microphone arrays. Due to its compact shape, the proposed microphone array greatly increases the feasibility of 3D soundfield analysis techniques in real-world applications.

Dimensional reduction in Bose-Einstein-condensed alkali-metal vapors

International Nuclear Information System (INIS)

Salasnich, L.; Reatto, L.; Parola, A.

2004-01-01

We investigate the effects of dimensional reduction in atomic Bose-Einstein condensates (BECs) induced by a strong harmonic confinement in the cylindric radial direction or in the cylindric axial direction. The former case corresponds to a transition from three dimensions (3D) to 1D in cigar-shaped BECs, while the latter case corresponds to a transition from 3D to 2D in disk-shaped BECs. We analyze the first sound velocity in axially homogeneous cigar-shaped BECs and in radially homogeneous disk-shaped BECs. We consider also the dimensional reduction in a BEC confined by a harmonic potential both in the radial direction and in the axial direction. By using a variational approach, we calculate monopole and quadrupole collective oscillations of the BEC. We find that the frequencies of these collective oscillations are related to the dimensionality and to the repulsive or attractive interatomic interaction

Direct and iterative algorithms for the parallel solution of the one-dimensional macroscopic Navier-Stokes equations

International Nuclear Information System (INIS)

Doster, J.M.; Sills, E.D.

1986-01-01

Current efforts are under way to develop and evaluate numerical algorithms for the parallel solution of the large sparse matrix equations associated with the finite difference representation of the macroscopic Navier-Stokes equations. Previous work has shown that these equations can be cast into smaller coupled matrix equations suitable for solution utilizing multiple computer processors operating in parallel. The individual processors themselves may exhibit parallelism through the use of vector pipelines. This wor, has concentrated on the one-dimensional drift flux form of the Navier-Stokes equations. Direct and iterative algorithms that may be suitable for implementation on parallel computer architectures are evaluated in terms of accuracy and overall execution speed. This work has application to engineering and training simulations, on-line process control systems, and engineering workstations where increased computational speeds are required

Direct electrochemistry and electrocatalysis of glucose oxidase on three-dimensional interpenetrating, porous graphene modified electrode

International Nuclear Information System (INIS)

Cui, Min; Xu, Bing; Hu, Chuangang; Shao, Hui Bo; Qu, Liangti

2013-01-01

Direct electrochemistry of glucose oxidase (GOD) on three-dimensional (3D) interpenetrating porous graphene electrodes has been reported, which have been fabricated by one-step electrochemical reduction of graphene oxide (GO) from its aqueous suspension. The electrochemically reduced GO (ERGO) modified electrodes exhibited excellent electron transfer properties for GOD and enhanced the enzyme activity and stability by the assistance of chitosan. The immobilized GOD shows a fast electron transfer with the rate constant (k s ) of 6.05 s −1 . It is worth mentioning that in the air-saturated phosphate buffer solution without any mediator, the resultant modified electrodes exhibited low detection limit of 1.7 μM with wide linear range of 0.02–3.2 mM and high sensitivity and high selectivity for measuring glucose. It would also be extended to various enzymes and bioactive molecules to develop the biosensor or other bio-electrochemical devices

Reversible Twisting of Primary Amides via Ground State N-C(O) Destabilization: Highly Twisted Rotationally Inverted Acyclic Amides.

Science.gov (United States)

Meng, Guangrong; Shi, Shicheng; Lalancette, Roger; Szostak, Roman; Szostak, Michal

2018-01-17

Since the seminal studies by Pauling in 1930s, planarity has become the defining characteristic of the amide bond. Planarity of amides has central implications for the reactivity and chemical properties of amides of relevance to a range of chemical disciplines. While the vast majority of amides are planar, nonplanarity has a profound effect on the properties of the amide bond, with the most common method to restrict the amide bond relying on the incorporation of the amide function into a rigid cyclic ring system. In a major departure from this concept, here, we report the first class of acyclic twisted amides that can be prepared, reversibly, from common primary amides in a single, operationally trivial step. Di-tert-butoxycarbonylation of the amide nitrogen atom yields twisted amides in which the amide bond exhibits nearly perpendicular twist. Full structural characterization of a range of electronically diverse compounds from this new class of twisted amides is reported. Through reactivity studies we demonstrate unusual properties of the amide bond, wherein selective cleavage of the amide bond can be achieved by a judicious choice of the reaction conditions. Through computational studies we evaluate structural and energetic details pertaining to the amide bond deformation. The ability to selectively twist common primary amides, in a reversible manner, has important implications for the design and application of the amide bond nonplanarity in structural chemistry, biochemistry and organic synthesis.

Acyclic retinoid in chemoprevention of hepatocellular carcinoma: Targeting phosphorylated retinoid X receptor-α for prevention of liver carcinogenesis

Directory of Open Access Journals (Sweden)

Masahito Shimizu

2012-01-01

Full Text Available One of the key features of hepatocellular carcinoma (HCC is the high rate of intrahepatic recurrence that correlates with poor prognosis. Therefore, in order to improve the clinical outcome for patients with HCC, development of a chemopreventive agent that can decrease or delay the incidence of recurrence is a critical issue for urgent investigation. Acyclic retinoid (ACR, a synthetic retinoid, successfully improves HCC patient survival by preventing recurrence and the formation of secondary tumors. A malfunction of the retinoid X receptor-α (RXRα due to phosphorylation by the Ras-MAPK signaling pathway plays a critical role in liver carcinogenesis, and ACR exerts chemopreventive effects on HCC development by inhibiting RXRα phosphorylation. Here, we review the relationship between retinoid signaling abnormalities and liver disease, the mechanisms of how RXRα phosphorylation contributes to liver carcinogenesis, and the detailed effects of ACR on preventing HCC development, especially based on the results of our basic and clinical research. We also outline the concept of "clonal deletion and inhibition" therapy, which is defined as the removal and inhibition of latent malignant clones from the liver before they expand into clinically detectable HCC, because ACR prevents the development of HCC by implementing this concept. Looking toward the future, we discuss "combination chemoprevention" using ACR as a key drug since it can generate a synergistic effect, and may thus be an effective new strategy for the prevention of HCC.

Magnetohydrodynamic study of three-dimensional instability of the spontaneous fast magnetic reconnection

International Nuclear Information System (INIS)

Shimizu, T.; Kondoh, K.; Ugai, M.; Shibata, K.

2009-01-01

Three-dimensional instability of the spontaneous fast magnetic reconnection is studied with magnetohydrodynamic (MHD) simulation, where the two-dimensional model of the spontaneous fast magnetic reconnection is destabilized in three dimension. Generally, in two-dimensional magnetic reconnection models, every plasma condition is assumed to be uniform in the sheet current direction. In such two-dimensional MHD simulations, the current sheet destabilized by the initial resistive disturbance can be developed to fast magnetic reconnection by a current driven anomalous resistivity. In this paper, the initial resistive disturbance includes a small amount of fluctuations in the sheet current direction, i.e., along the magnetic neutral line. The other conditions are the same as that of previous two-dimensional MHD studies for fast magnetic reconnection. Accordingly, we may expect that approximately two-dimensional fast magnetic reconnection occurs in the MHD simulation. In fact, the fast magnetic reconnection activated on the first stage of the simulation is two dimensional. However, on the subsequent stages, it spontaneously becomes three dimensional and is strongly localized in the sheet current direction. The resulting three-dimensional fast magnetic reconnection intermittently ejects three-dimensional magnetic loops. Such intermittent ejections of the three-dimensional loops are similar to the intermittent downflows observed in the solar flares. The ejection of the three-dimensional loops seems to be random but, numerically and theoretically, it is shown that the aspect ratio of the ejected loops is limited under a criterion.

The effect of base image window level selection on the dimensional measurement accuracy of resultant three-dimensional image displays

International Nuclear Information System (INIS)

Kurmis, A.P.; Hearn, T.C.; Reynolds, K.J.

2003-01-01

Purpose: The aim of this study was to determine the effect of base image window level selection on direct linear measurement of knee structures displayed using new magnetic resonance (MR)-based three-dimensional reconstructed computer imaging techniques. Methods: A prospective comparative study was performed using a series of three-dimensional knee images, generated from conventional MR imaging (MRI) sections. Thirty distinct anatomical structural features were identified within the image series of which repeated measurements were compared at 10 different window grey scale levels. Results: Statistical analysis demonstrated an excellent raw correlation between measurements and suggested no significant difference between measurements made at each of the 10 window level settings (P>0.05). Conclusions: The findings of this study suggest that unlike conventional MR or CT applications, grey scale window level selection at the time of imaging does not significantly affect the visual quality of resultant three-dimensional reconstructed images and hence the accuracy of subsequent direct linear measurement. The diagnostic potential of clinical progression from routine two-dimensional to advanced three-dimensional reconstructed imaging techniques may therefore be less likely to be degraded by inappropriate MR technician image windowing during the capturing of image series

Direct numerical simulation of a compressible boundary-layer flow past an isolated three-dimensional hump in a high-speed subsonic regime

Science.gov (United States)

De Grazia, D.; Moxey, D.; Sherwin, S. J.; Kravtsova, M. A.; Ruban, A. I.

2018-02-01

In this paper we study the boundary-layer separation produced in a high-speed subsonic boundary layer by a small wall roughness. Specifically, we present a direct numerical simulation (DNS) of a two-dimensional boundary-layer flow over a flat plate encountering a three-dimensional Gaussian-shaped hump. This work was motivated by the lack of DNS data of boundary-layer flows past roughness elements in a similar regime which is typical of civil aviation. The Mach and Reynolds numbers are chosen to be relevant for aeronautical applications when considering small imperfections at the leading edge of wings. We analyze different heights of the hump: The smaller heights result in a weakly nonlinear regime, while the larger result in a fully nonlinear regime with an increasing laminar separation bubble arising downstream of the roughness element and the formation of a pair of streamwise counterrotating vortices which appear to support themselves.

Water-Induced Dimensionality Reduction in Metal-Halide Perovskites

KAUST Repository

Turedi, Bekir; Lee, Kwangjae; Dursun, Ibrahim; Alamer, Badriah Jaber; Wu, Zhennan; Alarousu, Erkki; Mohammed, Omar F.; Cho, Namchul; Bakr, Osman

2018-01-01

. Here we employ water to directly transform films of the three-dimensional (3D) perovskite CsPbBr3 to stable two-dimensional (2D) perovskite-related CsPb2Br5. A sequential dissolution-recrystallization process governs this water induced transformation

Advancing three-dimensional MEMS by complimentary laser micro manufacturing

Science.gov (United States)

Palmer, Jeremy A.; Williams, John D.; Lemp, Tom; Lehecka, Tom M.; Medina, Francisco; Wicker, Ryan B.

2006-01-01

This paper describes improvements that enable engineers to create three-dimensional MEMS in a variety of materials. It also provides a means for selectively adding three-dimensional, high aspect ratio features to pre-existing PMMA micro molds for subsequent LIGA processing. This complimentary method involves in situ construction of three-dimensional micro molds in a stand-alone configuration or directly adjacent to features formed by x-ray lithography. Three-dimensional micro molds are created by micro stereolithography (MSL), an additive rapid prototyping technology. Alternatively, three-dimensional features may be added by direct femtosecond laser micro machining. Parameters for optimal femtosecond laser micro machining of PMMA at 800 nanometers are presented. The technical discussion also includes strategies for enhancements in the context of material selection and post-process surface finish. This approach may lead to practical, cost-effective 3-D MEMS with the surface finish and throughput advantages of x-ray lithography. Accurate three-dimensional metal microstructures are demonstrated. Challenges remain in process planning for micro stereolithography and development of buried features following femtosecond laser micro machining.

Quantum confinement effects in low-dimensional systems

Indian Academy of Sciences (India)

2015-06-03

Jun 3, 2015 ... Quantum confinement effects in low-dimensional systems. Figure 5. (a) Various cuts of the three-dimensional data showing energy vs. momen- tum dispersion relations for Ag film of 17 ML thickness on Ge(111). (b) Photo- emission intensity maps along ¯M– ¯ – ¯K direction. (c) Substrate bands replotted ...

Mapping and Scheduling of Directed Acyclic Graphs on An FPFA Tile

NARCIS (Netherlands)

Guo, Y.; Smit, Gerardus Johannes Maria

2002-01-01

An architecture for a hand-held multimedia device requires components that are energy-efficient, flexible, and provide high performance. In the CHAMELEON [4] project we develop a coarse grained reconfigurable device for DSP-like algorithms, the so-called Field Programmable Function Array (FPFA). The

Execution spaces for simple higher dimensional automata

DEFF Research Database (Denmark)

Raussen, Martin

2012-01-01

Higher dimensional automata (HDA) are highly expressive models for concurrency in Computer Science, cf van Glabbeek (Theor Comput Sci 368(1–2): 168–194, 2006). For a topologist, they are attractive since they can be modeled as cubical complexes—with an inbuilt restriction for directions of allowa......Higher dimensional automata (HDA) are highly expressive models for concurrency in Computer Science, cf van Glabbeek (Theor Comput Sci 368(1–2): 168–194, 2006). For a topologist, they are attractive since they can be modeled as cubical complexes—with an inbuilt restriction for directions...

Two-dimensional time-resolved X-ray diffraction study of directional solidification in steels

International Nuclear Information System (INIS)

Yonemura, Mitsuharu

2009-01-01

Full text: The high intensity heat source used for fusion welding creates steep thermal gradients of 100 degree C/s from 1800 degree Celsius. Further, the influence of a preferred orientation is serious for observation of a directional solidification that follows the dendrite growth along the direction toward the moving heat source. Therefore, we observed the rapid solidification of weld metal at a time resolution of 0.01∼0.1seconds by the Two-Dimensional Time-Resolved X-ray Diffraction (2DTRXRD) system for real welding. The diffraction ring was dynamically observed by 2DTRXRD during arc-passing over the irradiation area of X-ray with synchrotron energy of 18 KeV. The arc power output was 10 V - 150 A, and a scan speed of the arc was 1.0 mm/s. The temperature rise of instruments was suppressed by the water-cooled copper plate under the sample. Further, the temperature distribution of the weld metal was measured by the thermocouple and related to the diffraction patterns. Consequently, solidification and solid phase transformation of low carbon steels and stainless steels were observed during rapid cooling by 2DTRXRD. In the low-carbon steel, the microstructure is formed in the 2 step process; (i) formation of crystallites and (ii) increase of crystallinity. In the stainless steel, the irregular interface layer of σ/y in the quenched metal after solidification is expected that it is easy for dendrites to move at the lower temperature. In the carbide precipitation stainless steel, it is easy for NbC to grow on σ phase with a little under cooling. Further, a mist-like pattern, which differs from the halo-pattern, in the fusion zone gave some indication of the possibilities to observe the nucleation and the early solidification by 2DTRXRD. (author)

Laser bistatic two-dimensional scattering imaging simulation of lambert cone

Science.gov (United States)

Gong, Yanjun; Zhu, Chongyue; Wang, Mingjun; Gong, Lei

2015-11-01

This paper deals with the laser bistatic two-dimensional scattering imaging simulation of lambert cone. Two-dimensional imaging is called as planar imaging. It can reflect the shape of the target and material properties. Two-dimensional imaging has important significance for target recognition. The expression of bistatic laser scattering intensity of lambert cone is obtained based on laser radar eauqtion. The scattering intensity of a micro-element on the target could be obtained. The intensity is related to local angle of incidence, local angle of scattering and the infinitesimal area on the cone. According to the incident direction of laser, scattering direction and normal of infinitesimal area, the local incidence angle and scattering angle can be calculated. Through surface integration and the introduction of the rectangular function, we can get the intensity of imaging unit on the imaging surface, and then get Lambert cone bistatic laser two-dimensional scattering imaging simulation model. We analyze the effect of distinguishability, incident direction, observed direction and target size on the imaging. From the results, we can see that the scattering imaging simulation results of the lambert cone bistatic laser is correct.

Three Dimensional Polarimetric Neutron Tomography of Magnetic Fields

DEFF Research Database (Denmark)

Sales, Morten; Strobl, Markus; Shinohara, Takenao

2018-01-01

Through the use of Time-of-Flight Three Dimensional Polarimetric Neutron Tomography (ToF 3DPNT) we have for the first time successfully demonstrated a technique capable of measuring and reconstructing three dimensional magnetic field strengths and directions unobtrusively and non-destructively wi......Through the use of Time-of-Flight Three Dimensional Polarimetric Neutron Tomography (ToF 3DPNT) we have for the first time successfully demonstrated a technique capable of measuring and reconstructing three dimensional magnetic field strengths and directions unobtrusively and non...... and reconstructed, thereby providing the proof-of-principle of a technique able to reveal hitherto unobtainable information on the magnetic fields in the bulk of materials and devices, due to a high degree of penetration into many materials, including metals, and the sensitivity of neutron polarisation to magnetic...... fields. The technique puts the potential of the ToF time structure of pulsed neutron sources to full use in order to optimise the recorded information quality and reduce measurement time....

Application of three-dimensional reduced graphene oxide-gold composite modified electrode for direct electrochemistry and electrocatalysis of myoglobin.

Science.gov (United States)

Shi, Fan; Xi, Jingwen; Hou, Fei; Han, Lin; Li, Guangjiu; Gong, Shixing; Chen, Chanxing; Sun, Wei

2016-01-01

In this paper a three-dimensional (3D) reduced graphene oxide (RGO) and gold (Au) composite was synthesized by electrodeposition and used for the electrode modification with carbon ionic liquid electrode (CILE) as the substrate electrode. Myoglobin (Mb) was further immobilized on the surface of 3D RGO-Au/CILE to obtain an electrochemical sensing platform. Direct electrochemistry of Mb on the modified electrode was investigated with a pair of well-defined redox waves appeared on cyclic voltammogram, indicating the realization of direct electron transfer of Mb with the modified electrode. The results can be ascribed to the presence of highly conductive 3D RGO-Au composite on the electrode surface that accelerate the electron transfer rate between the electroactive center of Mb and the electrode. The Mb modified electrode showed excellent electrocatalytic activity to the reduction of trichloroacetic acid in the concentration range from 0.2 to 36.0 mmol/L with the detection limit of 0.06 mmol/L (3σ). Copyright © 2015 Elsevier B.V. All rights reserved.

Three-dimensional direct numerical simulation of electromagnetically driven multiscale shallow layer flows: Numerical modeling and physical properties

Science.gov (United States)

Lardeau, Sylvain; Ferrari, Simone; Rossi, Lionel

2008-12-01

Three-dimensional (3D) direct numerical simulations of a flow driven by multiscale electromagnetic forcing are performed in order to reproduce with maximum accuracy the quasi-two-dimensional (2D) flow generated by the same multiscale forcing in the laboratory. The method presented is based on a 3D description of the flow and the electromagnetic forcing. Very good agreements between our simulations and the experiments are found both on velocity and acceleration field, this last comparison being, to our knowledge, done for the first time. Such agreement requires that both experiments and simulations are carefully performed and, more importantly, that the underlying simplification to model the experiments and the multiscale electromagnetic forcing do not introduce significant errors. The results presented in this paper differ significantly from previous 2D direct numerical simulation in which a classical linear Rayleigh friction modeling term was used to mimic the effect of the wall-normal friction. Indeed, purely 2D simulations are found to underestimate the Reynolds number and, due to the dominance of nonhomogeneous bottom friction, lead to the wrong physical mechanism. For the range of conditions presented in this paper, the Reynolds number, defined by the ratio between acceleration and viscous terms, remains the order of unity, and the Hartmann number, defined by the ratio between electromagnetic force terms and viscous terms, is about 2. The main conclusion is that 3D simulations are required to model the (3D) electromagnetic forces and the wall-normal shear. Indeed, even if the flow is quasi-2D in terms of energy, a full 3D approach is required to simulate these shallow layer flows driven by multiscale electromagnetic forcing. In the range of forcing intensity investigated in this paper, these multiscale flows remain quasi-2D, with negligible energy in the wall-normal velocity component. It is also shown that the driving terms are the electromagnetic forcing and

Synthetic incorporation of Nile Blue into DNA using 2′-deoxyriboside substitutes: Representative comparison of (R- and (S-aminopropanediol as an acyclic linker

Directory of Open Access Journals (Sweden)

Daniel Lachmann

2010-02-01

Full Text Available The Nile Blue chromophore was incorporated into oligonucleotides using “click” chemistry for the postsynthetic modification of oligonucleotides. These were synthesized using DNA building block 3 bearing an alkyne group and reacted with the azide 4. (R-3-amino-1,2-propanediol was applied as the linker between the phosphodiester bridges. Two sets of DNA duplexes were prepared. One set carried the chromophore in an A-T environment, the second set in a G-C environment. Both were characterized by optical spectroscopy. Sequence-dependent fluorescence quenching was applied as a sensitive tool to compare the stacking interactions with respect to the chirality of the acyclic linker attachment. The results were compared to recent results from duplexes that carried the Nile Blue label in a sequentially and structurally identical context, except for the opposite chirality of the linker ((S-3-amino-1,2-propandiol. Only minor, negligible differences were observed. Melting temperatures, UV–vis absorption spectra together with fluorescence quenching data indicate that Nile Blue stacks perfectly between the adjacent base pairs regardless of whether it has been attached via an S- or R-configured linker. This result was supported by geometrically optimized DNA models.

Direct correlations of structural and optical properties of three-dimensional GaN/InGaN core/shell micro-light emitting diodes

Science.gov (United States)

Sadat Mohajerani, Matin; Müller, Marcus; Hartmann, Jana; Zhou, Hao; Wehmann, Hergo-H.; Veit, Peter; Bertram, Frank; Christen, Jürgen; Waag, Andreas

2016-05-01

Three-dimensional (3D) InGaN/GaN quantum-well (QW) core-shell light emitting diodes (LEDs) are a promising candidate for the future solid state lighting. In this contribution, we study direct correlations of structural and optical properties of the core-shell LEDs using highly spatially-resolved cathodoluminescence spectroscopy (CL) in combination with scanning electron microscopy (SEM) and scanning transmission electron microscopy (STEM). Temperature-dependent resonant photoluminescence (PL) spectroscopy has been performed to understand recombination mechanisms and to estimate the internal quantum efficiency (IQE).

Start-up flow in a three-dimensional lid-driven cavity by means of a massively parallel direction splitting algorithm

KAUST Repository

Guermond, J. L.

2011-05-04

The purpose of this paper is to validate a new highly parallelizable direction splitting algorithm. The parallelization capabilities of this algorithm are illustrated by providing a highly accurate solution for the start-up flow in a three-dimensional impulsively started lid-driven cavity of aspect ratio 1×1×2 at Reynolds numbers 1000 and 5000. The computations are done in parallel (up to 1024 processors) on adapted grids of up to 2 billion nodes in three space dimensions. Velocity profiles are given at dimensionless times t=4, 8, and 12; at least four digits are expected to be correct at Re=1000. © 2011 John Wiley & Sons, Ltd.

Pentadiagonal alternating-direction-implicit finite-difference time-domain method for two-dimensional Schrödinger equation

Science.gov (United States)

Tay, Wei Choon; Tan, Eng Leong

2014-07-01

In this paper, we have proposed a pentadiagonal alternating-direction-implicit (Penta-ADI) finite-difference time-domain (FDTD) method for the two-dimensional Schrödinger equation. Through the separation of complex wave function into real and imaginary parts, a pentadiagonal system of equations for the ADI method is obtained, which results in our Penta-ADI method. The Penta-ADI method is further simplified into pentadiagonal fundamental ADI (Penta-FADI) method, which has matrix-operator-free right-hand-sides (RHS), leading to the simplest and most concise update equations. As the Penta-FADI method involves five stencils in the left-hand-sides (LHS) of the pentadiagonal update equations, special treatments that are required for the implementation of the Dirichlet's boundary conditions will be discussed. Using the Penta-FADI method, a significantly higher efficiency gain can be achieved over the conventional Tri-ADI method, which involves a tridiagonal system of equations.

Decoherence in two-dimensional quantum walks

International Nuclear Information System (INIS)

Oliveira, A. C.; Portugal, R.; Donangelo, R.

2006-01-01

We analyze the decoherence in quantum walks in two-dimensional lattices generated by broken-link-type noise. In this type of decoherence, the links of the lattice are randomly broken with some given constant probability. We obtain the evolution equation for a quantum walker moving on two-dimensional (2D) lattices subject to this noise, and we point out how to generalize for lattices in more dimensions. In the nonsymmetric case, when the probability of breaking links in one direction is different from the probability in the perpendicular direction, we have obtained a nontrivial result. If one fixes the link-breaking probability in one direction, and gradually increases the probability in the other direction from 0 to 1, the decoherence initially increases until it reaches a maximum value, and then it decreases. This means that, in some cases, one can increase the noise level and still obtain more coherence. Physically, this can be explained as a transition from a decoherent 2D walk to a coherent 1D walk

Two-dimensional wave propagation in layered periodic media

KAUST Repository

Quezada de Luna, Manuel

2014-09-16

We study two-dimensional wave propagation in materials whose properties vary periodically in one direction only. High order homogenization is carried out to derive a dispersive effective medium approximation. One-dimensional materials with constant impedance exhibit no effective dispersion. We show that a new kind of effective dispersion may arise in two dimensions, even in materials with constant impedance. This dispersion is a macroscopic effect of microscopic diffraction caused by spatial variation in the sound speed. We analyze this dispersive effect by using highorder homogenization to derive an anisotropic, dispersive effective medium. We generalize to two dimensions a homogenization approach that has been used previously for one-dimensional problems. Pseudospectral solutions of the effective medium equations agree to high accuracy with finite volume direct numerical simulations of the variable-coeffi cient equations.

Factorizations of one-dimensional classical systems

International Nuclear Information System (INIS)

Kuru, Senguel; Negro, Javier

2008-01-01

A class of one-dimensional classical systems is characterized from an algebraic point of view. The Hamiltonians of these systems are factorized in terms of two functions that together with the Hamiltonian itself close a Poisson algebra. These two functions lead directly to two time-dependent integrals of motion from which the phase motions are derived algebraically. The systems so obtained constitute the classical analogues of the well known factorizable one-dimensional quantum mechanical systems

Four-dimensional Printing of Liquid Crystal Elastomers.

Science.gov (United States)

Ambulo, Cedric P; Burroughs, Julia J; Boothby, Jennifer M; Kim, Hyun; Shankar, M Ravi; Ware, Taylor H

2017-10-25

Three-dimensional structures capable of reversible changes in shape, i.e., four-dimensional-printed structures, may enable new generations of soft robotics, implantable medical devices, and consumer products. Here, thermally responsive liquid crystal elastomers (LCEs) are direct-write printed into 3D structures with a controlled molecular order. Molecular order is locally programmed by controlling the print path used to build the 3D object, and this order controls the stimulus response. Each aligned LCE filament undergoes 40% reversible contraction along the print direction on heating. By printing objects with controlled geometry and stimulus response, magnified shape transformations, for example, volumetric contractions or rapid, repetitive snap-through transitions, are realized.

MAGNETOHYDRODYNAMICS STUDY OF THREE-DIMENSIONAL FAST MAGNETIC RECONNECTION FOR INTERMITTENT SNAKE-LIKE DOWNFLOWS IN SOLAR FLARES

International Nuclear Information System (INIS)

Shimizu, T.; Kondo, K.; Ugai, M.; Shibata, K.

2009-01-01

Three-dimensional instability of the spontaneous fast magnetic reconnection is studied with magnetohydrodynamics (MHD) simulation, where the two-dimensional model of the spontaneous fast magnetic reconnection is destabilized in three dimensions. In two-dimensional models, every plasma condition is assumed to be uniform in the sheet current direction. In that case, it is well known that the two-dimensional fast magnetic reconnection can be caused by current-driven anomalous resistivity, when an initial resistive disturbance is locally put in a one-dimensional current sheet. In this paper, it is studied whether the two-dimensional fast magnetic reconnection can be destabilized or not when the initial resistive disturbance is three dimensional, i.e., that which has weak fluctuations in the sheet current direction. According to our study, the two-dimensional fast magnetic reconnection is developed to the three-dimensional intermittent fast magnetic reconnection which is strongly localized in the sheet current direction. The resulting fast magnetic reconnection repeats to randomly eject three-dimensional magnetic loops which are very similar to the intermittent downflows observed in solar flares. In fact, in some observations of solar flares, the current sheet seems to be approximately one dimensional, but the fast magnetic reconnection is strongly localized in the sheet current direction, i.e., fully three dimensional. In addition, the observed plasma downflows as snake-like curves. It is shown that those observed features are consistent with our numerical MHD study.

Direct fabrication of high-resolution three-dimensional polymeric scaffolds using electrohydrodynamic hot jet plotting

International Nuclear Information System (INIS)

Wei, Chuang; Dong, Jingyan

2013-01-01

This paper presents the direct three-dimensional (3D) fabrication of polymer scaffolds with sub-10 µm structures using electrohydrodynamic jet (EHD-jet) plotting of melted thermoplastic polymers. Traditional extrusion-based fabrication approaches of 3D periodic porous structures are very limited in their resolution, due to the excessive pressure requirement for extruding highly viscous thermoplastic polymers. EHD-jet printing has become a high-resolution alternative to other forms of nozzle deposition-based fabrication approaches by generating micro-scale liquid droplets or a fine jet through the application of a large electrical voltage between the nozzle and the substrate. In this study, we successfully apply EHD-jet plotting technology with melted biodegradable polymer (polycaprolactone, or PCL) for the fabrication of 2D patterns and 3D periodic porous scaffold structures in potential tissue engineering applications. Process conditions (e.g. electrical voltage, pressure, plotting speed) have been thoroughly investigated to achieve reliable jet printing of fine filaments. We have demonstrated for the first time that the EHD-jet plotting process is capable of the fabrication of 3D periodic structures with sub-10 µm resolution, which has great potential in advanced biomedical applications, such as cell alignment and guidance. (paper)

Three-dimensional fabric analysis for anisotropic material using multi-directional scanning line. Application to x-ray CI image

International Nuclear Information System (INIS)

Takemura, Takato; Takahashi, Manabu; Oda, Masanobu; Hirai, Hidekazu; Murakoshi, Atsushi; Miura, Makoto

2007-01-01

In microscopic analysis, materials are characterized by a three-dimensional (3D) microstructure which is composed of constituent elements such as pores, voids and cracks. A material's mechanical and hydrological properties are strongly dependent on its microstructure. In order to discuss the mechanics of geomaterials on a microstructural level, detailed information on their 3D macrostructure is required. X-ray computed tomography is a powerful non-destructive method for determining the microstructure, however it can be difficult to determine a material's microstructure from the reconstructed 3D image. We successfully evaluated the 3D microstructural anisotropy of porous and fibrous materials using a multi-directional scanning line method that employs straightforward image analysis, and its results were visualized using stereonet projection. (author)

Antitenascin antibody 81C6 armed with {sup 177}Lu: in vivo comparison of macrocyclic and acyclic ligands

Energy Technology Data Exchange (ETDEWEB)

Yordanov, Alexander T. [Department of Radiology, Duke University Medical Center Durham, NC 27710 (United States); Hens, Marc [Department of Radiology, Duke University Medical Center Durham, NC 27710 (United States); Pegram, Charles [Department of Pathology, Duke University Medical Center Durham, NC 27710 (United States); Bigner, Darell D. [Department of Pathology, Duke University Medical Center Durham, NC 27710 (United States); Zalutsky, Michael R. [Department of Radiology, Duke University Medical Center Durham, NC 27710 (United States)]. E-mail: zalut001@mc.duke.edu

2007-02-15

Introduction: When labeled with iodine-131, the antitenascin monoclonal antibody (mAb) 81C6 has shown promise as a targeted radiotherapeutic in patients with brain tumors. Because of its more favorable {gamma}-ray properties, lutetium-177 might be a better low-energy {beta}-emitter for this type of therapy. Materials and Methods: Chimeric 81C6 (ch81C6) was labeled with {sup 177}Lu using the acyclic 1B4M ligand and the macrocyclic ligands NHS-DOTA and MeO-DOTA and evaluated for binding to tenascin. Three paired-label tissue distribution experiments were performed in normal mice receiving one of the {sup 177}Lu-labeled immunoconjugates plus {sup 125}I-labeled ch81C6 labeled using Iodogen. Paired-label experiments in athymic mice bearing subcutaneous D54 MG human glioma xenografts were done to directly compare the biodistribution of ch81C6-1B4M-{sup 177}Lu and {sup 125}I-labeled ch81C6, and ch81C6-MeO-DOTA-{sup 177}Lu and {sup 125}I-labeled ch81C6. Similar comparisons were done using murine (mu) instead of ch81C6. The primary parameter utilized for evaluation was the {sup 177}Lu/{sup 125}I uptake ratio in each tissue. Results: In the studies performed in normal mice, the NHS-DOTA ligand yielded the highest {sup 177}Lu/{sup 125}I uptake ratios in tissues indicative of loss of label from the chelate; for this reason, only 1B4M and MeO-DOTA were evaluated further. The {sup 177}Lu/{sup 125}I ratio in bone increased gradually with time for the chimeric conjugates; however, there were no significant differences between ch81C6-1B4M-DTPA-{sup 177}Lu and ch81C6-MeO-DOTA-{sup 177}Lu. In contrast, mu81C6-1B4M-DTPA-{sup 177}Lu and mu81C6-MeO-DOTA-{sup 177}Lu showed a more dramatic increase in the {sup 177}Lu/{sup 125}I ratio in bone - from 2.4{+-}0.3 and 1.7{+-}0.2 at Day 1 to 8.5{+-}1.1 and 4.2{+-}0.5 at Day 7, respectively. Conclusion: With these antitenascin constructs, the nature of the mAb had a profound influence on the relative degree of loss of {sup 177}Lu from these

Data-driven execution of fast multipole methods

KAUST Repository

Ltaief, Hatem; Yokota, Rio

2013-01-01

time-consuming stages of the FMMs into smaller tasks. The algorithm can then be represented as a directed acyclic graph where nodes represent tasks and edges represent dependencies among them. The execution of the algorithm is performed

New method for solving three-dimensional Schroedinger equation

International Nuclear Information System (INIS)

Melezhik, V.S.

1990-01-01

The method derived recently for solving a multidimensional scattering problem is applied to a three-dimensional Schroedinger equation. As compared with direct three-dimensional calculations of finite elements and finite differences, this approach gives sufficiently accurate upper and lower approximations to the helium-atom binding energy, which demonstrates its efficiency. 15 refs.; 1 fig.; 2 tabs

Direct experimental visualization of the global Hamiltonian progression of two-dimensional Lagrangian flow topologies from integrable to chaotic state

Energy Technology Data Exchange (ETDEWEB)

Baskan, O.; Clercx, H. J. H [Fluid Dynamics Laboratory, Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands); Speetjens, M. F. M. [Energy Technology Laboratory, Department of Mechanical Engineering, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands); Metcalfe, G. [Commonwealth Scientific and Industrial Research Organisation, Melbourne, Victoria 3190 (Australia); Swinburne University of Technology, Department of Mechanical Engineering, Hawthorn VIC 3122 (Australia)

2015-10-15

Countless theoretical/numerical studies on transport and mixing in two-dimensional (2D) unsteady flows lean on the assumption that Hamiltonian mechanisms govern the Lagrangian dynamics of passive tracers. However, experimental studies specifically investigating said mechanisms are rare. Moreover, they typically concern local behavior in specific states (usually far away from the integrable state) and generally expose this indirectly by dye visualization. Laboratory experiments explicitly addressing the global Hamiltonian progression of the Lagrangian flow topology entirely from integrable to chaotic state, i.e., the fundamental route to efficient transport by chaotic advection, appear non-existent. This motivates our study on experimental visualization of this progression by direct measurement of Poincaré sections of passive tracer particles in a representative 2D time-periodic flow. This admits (i) accurate replication of the experimental initial conditions, facilitating true one-to-one comparison of simulated and measured behavior, and (ii) direct experimental investigation of the ensuing Lagrangian dynamics. The analysis reveals a close agreement between computations and observations and thus experimentally validates the full global Hamiltonian progression at a great level of detail.

Direct experimental visualization of the global Hamiltonian progression of two-dimensional Lagrangian flow topologies from integrable to chaotic state.

Science.gov (United States)

Baskan, O; Speetjens, M F M; Metcalfe, G; Clercx, H J H

2015-10-01

Countless theoretical/numerical studies on transport and mixing in two-dimensional (2D) unsteady flows lean on the assumption that Hamiltonian mechanisms govern the Lagrangian dynamics of passive tracers. However, experimental studies specifically investigating said mechanisms are rare. Moreover, they typically concern local behavior in specific states (usually far away from the integrable state) and generally expose this indirectly by dye visualization. Laboratory experiments explicitly addressing the global Hamiltonian progression of the Lagrangian flow topology entirely from integrable to chaotic state, i.e., the fundamental route to efficient transport by chaotic advection, appear non-existent. This motivates our study on experimental visualization of this progression by direct measurement of Poincaré sections of passive tracer particles in a representative 2D time-periodic flow. This admits (i) accurate replication of the experimental initial conditions, facilitating true one-to-one comparison of simulated and measured behavior, and (ii) direct experimental investigation of the ensuing Lagrangian dynamics. The analysis reveals a close agreement between computations and observations and thus experimentally validates the full global Hamiltonian progression at a great level of detail.

Controlled teleportation of a 3-dimensional bipartite quantum state

International Nuclear Information System (INIS)

Cao Haijing; Chen Zhonghua; Song Heshan

2008-01-01

A controlled teleportation scheme of an unknown 3-dimensional (3D) two-particle quantum state is proposed, where a 3D Bell state and 3D GHZ state function as the quantum channel. This teleportation scheme can be directly generalized to teleport an unknown d-dimensional bipartite quantum state

Experimental Investigation on Low-velocity Impact and Compression After Impact Properties of Three-dimensional Five-directional Braided Composites

Directory of Open Access Journals (Sweden)

YAN Shi

2017-12-01

Full Text Available The low-velocity impact and compression after impact (CAI properties of three-dimensional (3D five-directional carbon fiber/epoxy resin braided composites were experimentally investigated. Specimens prepared with different braiding angles were tested at the same impact energy level. Residual post-impact mechanical properties of the different configurations were characterized by compression after impact tests. Results show that the specimens with bigger braiding angle sustain higher peak loads, and smaller impact damage area, mainly attributes to a more compact space construction. The CAI strength and damage mechanism are found to be mainly dependent on the axial support of the braiding fiber tows. With the increase of braiding angle, the CAI strength decreases, and the damage mode of the composites is changed from transverse fracture to shear failure.

Estimation of three-dimensional radar tracking using modified extended kalman filter

Science.gov (United States)

Aditya, Prima; Apriliani, Erna; Khusnul Arif, Didik; Baihaqi, Komar

2018-03-01

Kalman filter is an estimation method by combining data and mathematical models then developed be extended Kalman filter to handle nonlinear systems. Three-dimensional radar tracking is one of example of nonlinear system. In this paper developed a modification method of extended Kalman filter from the direct decline of the three-dimensional radar tracking case. The development of this filter algorithm can solve the three-dimensional radar measurements in the case proposed in this case the target measured by radar with distance r, azimuth angle θ, and the elevation angle ϕ. Artificial covariance and mean adjusted directly on the three-dimensional radar system. Simulations result show that the proposed formulation is effective in the calculation of nonlinear measurement compared with extended Kalman filter with the value error at 0.77% until 1.15%.

One-dimensional metallic edge states in MoS2

DEFF Research Database (Denmark)

Bollinger, Mikkel; Lauritsen, J.V.; Jacobsen, Karsten Wedel

2001-01-01

By the use of density functional calculations it is shown that the edges of a two-dimensional slab of insulating MoS2 exhibit several metallic states. These edge states can be viewed as one-dimensional conducting wires, and we show that they can be observed directly using scanning tunneling...

Suspended liquid subtractive lithography: printing three dimensional channels directly into uncured PDMS

Science.gov (United States)

Helmer, D.; Voigt, A.; Wagner, S.; Keller, N.; Sachsenheimer, K.; Kotz, F.; Nargang, T. M.; Rapp, B. E.

2018-02-01

Polydimethylsiloxane (PDMS) is one of the most widely used polymers for the generation of microfluidic chips. The standard procedures of soft lithography require the formation of a new master structure for every design which is timeconsuming and expensive. All channel generated by soft lithography need to be consecutively sealed by bonding which is a process that can proof to be hard to control. Channel cross-sections are largely restricted to squares or flat-topped designs and the generation of truly three-dimensional designs is not straightforward. Here we present Suspended Liquid Subtractive Lithography (SLSL) a method for generating microfluidic channels of nearly arbitrary three-dimensional structures in PDMS that do not require master formation or bonding and give circular channel cross sections which are especially interesting for mimicking in vivo environments. In SLSL, an immiscible liquid is introduced into the uncured PDMS by a capillary mounted on a 3D printer head. The liquid forms continuous "threads" inside the matrix thus creating void suspended channel structures.

The Use of Sparse Direct Solver in Vector Finite Element Modeling for Calculating Two Dimensional (2-D) Magnetotelluric Responses in Transverse Electric (TE) Mode

Science.gov (United States)

Yihaa Roodhiyah, Lisa’; Tjong, Tiffany; Nurhasan; Sutarno, D.

2018-04-01

The late research, linear matrices of vector finite element in two dimensional(2-D) magnetotelluric (MT) responses modeling was solved by non-sparse direct solver in TE mode. Nevertheless, there is some weakness which have to be improved especially accuracy in the low frequency (10-3 Hz-10-5 Hz) which is not achieved yet and high cost computation in dense mesh. In this work, the solver which is used is sparse direct solver instead of non-sparse direct solverto overcome the weaknesses of solving linear matrices of vector finite element metod using non-sparse direct solver. Sparse direct solver will be advantageous in solving linear matrices of vector finite element method because of the matrix properties which is symmetrical and sparse. The validation of sparse direct solver in solving linear matrices of vector finite element has been done for a homogen half-space model and vertical contact model by analytical solution. Thevalidation result of sparse direct solver in solving linear matrices of vector finite element shows that sparse direct solver is more stable than non-sparse direct solver in computing linear problem of vector finite element method especially in low frequency. In the end, the accuracy of 2D MT responses modelling in low frequency (10-3 Hz-10-5 Hz) has been reached out under the efficient allocation memory of array and less computational time consuming.

Mode selection in two-dimensional Bragg resonators based on planar dielectric waveguides

International Nuclear Information System (INIS)

Baryshev, V R; Ginzburg, N S; Zaslavskii, V Yu; Malkin, A M; Sergeev, A S; Thumm, M

2009-01-01

Two-dimensional Bragg resonators based on planar dielectric waveguides are analysed. It is shown that the doubly periodic corrugation deposited on the dielectric surface in the form of two gratings with translational vectors directed perpendicular to each other ensures effective selection of modes along two coordinates at large Fresnel parameters. This result is obtained both by the method of coupled waves (geometrical optics approximation) and by the direct numerical simulations. Two-dimensional Bragg resonators make it possible to fabricate two-dimensional distributed feedback lasers and to provide generation of spatially coherent radiation in large-volume active media. (waveguides)

Two-dimensional simulation of sintering process

International Nuclear Information System (INIS)

Vasconcelos, Vanderley de; Pinto, Lucio Carlos Martins; Vasconcelos, Wander L.

1996-01-01

The results of two-dimensional simulations are directly applied to systems in which one of the dimensions is much smaller than the others, and to sections of three dimensional models. Moreover, these simulations are the first step of the analysis of more complex three-dimensional systems. In this work, two basic features of the sintering process are studied: the types of particle size distributions related to the powder production processes and the evolution of geometric parameters of the resultant microstructures during the solid-state sintering. Random packing of equal spheres is considered in the sintering simulation. The packing algorithm does not take into account the interactive forces between the particles. The used sintering algorithm causes the densification of the particle set. (author)

Heat transport in two-dimensional materials by directly solving the phonon Boltzmann equation under Callaway's dual relaxation model

Science.gov (United States)

Guo, Yangyu; Wang, Moran

2017-10-01

The single mode relaxation time approximation has been demonstrated to greatly underestimate the lattice thermal conductivity of two-dimensional materials due to the collective effect of phonon normal scattering. Callaway's dual relaxation model represents a good approximation to the otherwise ab initio solution of the phonon Boltzmann equation. In this work we develop a discrete-ordinate-method (DOM) scheme for the numerical solution of the phonon Boltzmann equation under Callaway's model. Heat transport in a graphene ribbon with different geometries is modeled by our scheme, which produces results quite consistent with the available molecular dynamics, Monte Carlo simulations, and experimental measurements. Callaway's lattice thermal conductivity model with empirical boundary scattering rates is examined and shown to overestimate or underestimate the direct DOM solution. The length convergence of the lattice thermal conductivity of a rectangular graphene ribbon is explored and found to depend appreciably on the ribbon width, with a semiquantitative correlation provided between the convergence length and the width. Finally, we predict the existence of a phonon Knudsen minimum in a graphene ribbon only at a low system temperature and isotope concentration so that the average normal scattering rate is two orders of magnitude stronger than the intrinsic resistive one. The present work will promote not only the methodology for the solution of the phonon Boltzmann equation but also the theoretical modeling and experimental detection of hydrodynamic phonon transport in two-dimensional materials.

Dimensionality reduction of collective motion by principal manifolds

Science.gov (United States)

Gajamannage, Kelum; Butail, Sachit; Porfiri, Maurizio; Bollt, Erik M.

2015-01-01

While the existence of low-dimensional embedding manifolds has been shown in patterns of collective motion, the current battery of nonlinear dimensionality reduction methods is not amenable to the analysis of such manifolds. This is mainly due to the necessary spectral decomposition step, which limits control over the mapping from the original high-dimensional space to the embedding space. Here, we propose an alternative approach that demands a two-dimensional embedding which topologically summarizes the high-dimensional data. In this sense, our approach is closely related to the construction of one-dimensional principal curves that minimize orthogonal error to data points subject to smoothness constraints. Specifically, we construct a two-dimensional principal manifold directly in the high-dimensional space using cubic smoothing splines, and define the embedding coordinates in terms of geodesic distances. Thus, the mapping from the high-dimensional data to the manifold is defined in terms of local coordinates. Through representative examples, we show that compared to existing nonlinear dimensionality reduction methods, the principal manifold retains the original structure even in noisy and sparse datasets. The principal manifold finding algorithm is applied to configurations obtained from a dynamical system of multiple agents simulating a complex maneuver called predator mobbing, and the resulting two-dimensional embedding is compared with that of a well-established nonlinear dimensionality reduction method.

Toward three-dimensional microelectronic systems: directed self-assembly of silicon microcubes via DNA surface functionalization.

Science.gov (United States)

Lämmerhardt, Nico; Merzsch, Stephan; Ledig, Johannes; Bora, Achyut; Waag, Andreas; Tornow, Marc; Mischnick, Petra

2013-07-02

The huge and intelligent processing power of three-dimensional (3D) biological "processors" like the human brain with clock speeds of only 0.1 kHz is an extremely fascinating property, which is based on a massively parallel interconnect strategy. Artificial silicon microprocessors are 7 orders of magnitude faster. Nevertheless, they do not show any indication of intelligent processing power, mostly due to their very limited interconnectivity. Massively parallel interconnectivity can only be realized in three dimensions. Three-dimensional artificial processors would therefore be at the root of fabricating artificially intelligent systems. A first step in this direction would be the self-assembly of silicon based building blocks into 3D structures. We report on the self-assembly of such building blocks by molecular recognition, and on the electrical characterization of the formed assemblies. First, planar silicon substrates were functionalized with self-assembling monolayers of 3-aminopropyltrimethoxysilane for coupling of oligonucleotides (single stranded DNA) with glutaric aldehyde. The oligonucleotide immobilization was confirmed and quantified by hybridization with fluorescence-labeled complementary oligonucleotides. After the individual processing steps, the samples were analyzed by contact angle measurements, ellipsometry, atomic force microscopy, and fluorescence microscopy. Patterned DNA-functionalized layers were fabricated by microcontact printing (μCP) and photolithography. Silicon microcubes of 3 μm edge length as model objects for first 3D self-assembly experiments were fabricated out of silicon-on-insulator (SOI) wafers by a combination of reactive ion etching (RIE) and selective wet etching. The microcubes were then surface-functionalized using the same protocol as on planar substrates, and their self-assembly was demonstrated both on patterned silicon surfaces (88% correctly placed cubes), and to cube aggregates by complementary DNA

Optical conductivity of three and two dimensional topological nodal-line semimetals

Science.gov (United States)

Barati, Shahin; Abedinpour, Saeed H.

2017-10-01

The peculiar shape of the Fermi surface of topological nodal-line semimetals at low carrier concentrations results in their unusual optical and transport properties. We analytically investigate the linear optical responses of three- and two-dimensional nodal-line semimetals using the Kubo formula. The optical conductivity of a three-dimensional nodal-line semimetal is anisotropic. Along the axial direction (i.e., the direction perpendicular to the nodal-ring plane), the Drude weight has a linear dependence on the chemical potential at both low and high carrier dopings. For the radial direction (i.e., the direction parallel to the nodal-ring plane), this dependence changes from linear into quadratic in the transition from low into high carrier concentration. The interband contribution into optical conductivity is also anisotropic. In particular, at large frequencies, it saturates to a constant value for the axial direction and linearly increases with frequency along the radial direction. In two-dimensional nodal-line semimetals, no interband optical transition could be induced and the only contribution to the optical conductivity arises from the intraband excitations. The corresponding Drude weight is independent of the carrier density at low carrier concentrations and linearly increases with chemical potential at high carrier doping.

Exact solutions of Einstein and Einstein-Maxwell equations in higher-dimensional spacetime

International Nuclear Information System (INIS)

Xu Dianyan; Beijing Univ., BJ

1988-01-01

The D-dimensional Schwarzschild-de Sitter metric and Reissner-Nordstrom-de-Sitter metric are derived directly by solving the Einstein and Einstein-Maxwell equations. The D-dimensional Kerr metric is rederived by using the complex coordinate transformation method and the D-dimensional Kerr-de Sitter metric is also given. The conjecture about the D-dimensional metric of a rotating charged mass is given at the end of this paper. (author)

The effect of acyclic retinoid on the metabolomic profiles of hepatocytes and hepatocellular carcinoma cells.

Directory of Open Access Journals (Sweden)

Xian-Yang Qin

Full Text Available BACKGROUND/PURPOSE: Acyclic retinoid (ACR is a promising chemopreventive agent for hepatocellular carcinoma (HCC that selectively inhibits the growth of HCC cells (JHH7 but not normal hepatic cells (Hc. To better understand the molecular basis of the selective anti-cancer effect of ACR, we performed nuclear magnetic resonance (NMR-based and capillary electrophoresis time-of-flight mass spectrometry (CE-TOFMS-based metabolome analyses in JHH7 and Hc cells after treatment with ACR. METHODOLOGY/PRINCIPAL FINDINGS: NMR-based metabolomics revealed a distinct metabolomic profile of JHH7 cells at 18 h after ACR treatment but not at 4 h after ACR treatment. CE-TOFMS analysis identified 88 principal metabolites in JHH7 and Hc cells after 24 h of treatment with ethanol (EtOH or ACR. The abundance of 71 of these metabolites was significantly different between EtOH-treated control JHH7 and Hc cells, and 49 of these metabolites were significantly down-regulated in the ACR-treated JHH7 cells compared to the EtOH-treated JHH7 cells. Of particular interest, the increase in adenosine-5'-triphosphate (ATP, the main cellular energy source, that was observed in the EtOH-treated control JHH7 cells was almost completely suppressed in the ACR-treated JHH7 cells; treatment with ACR restored ATP to the basal levels observed in both EtOH-control and ACR-treated Hc cells (0.72-fold compared to the EtOH control-treated JHH7 cells. Moreover, real-time PCR analyses revealed that ACR significantly increased the expression of pyruvate dehydrogenase kinases 4 (PDK4, a key regulator of ATP production, in JHH7 cells but not in Hc cells (3.06-fold and 1.20-fold compared to the EtOH control, respectively. CONCLUSIONS/SIGNIFICANCE: The results of the present study suggest that ACR may suppress the enhanced energy metabolism of JHH7 cells but not Hc cells; this occurs at least in part via the cancer-selective enhancement of PDK4 expression. The cancer-selective metabolic pathways

Three-dimensional echocardiographic assessment of the repaired mitral valve.

Science.gov (United States)

Maslow, Andrew; Mahmood, Feroze; Poppas, Athena; Singh, Arun

2014-02-01

This study examined the geometric changes of the mitral valve (MV) after repair using conventional and three-dimensional echocardiography. Prospective evaluation of consecutive patients undergoing mitral valve repair. Tertiary care university hospital. Fifty consecutive patients scheduled for elective repair of the mitral valve for regurgitant disease. Intraoperative transesophageal echocardiography. Assessments of valve area (MVA) were performed using two-dimensional planimetry (2D-Plan), pressure half-time (PHT), and three-dimensional planimetry (3D-Plan). In addition, the direction of ventricular inflow was assessed from the three-dimensional imaging. Good correlations (r = 0.83) and agreement (-0.08 +/- 0.43 cm(2)) were seen between the MVA measured with 3D-Plan and PHT, and were better than either compared to 2D-Plan. MVAs were smaller after repair of functional disease repaired with an annuloplasty ring. After repair, ventricular inflow was directed toward the lateral ventricular wall. Subgroup analysis showed that the change in inflow angle was not different after repair of functional disease (168 to 171 degrees) as compared to those presenting with degenerative disease (168 to 148 degrees; p<0.0001). Three-dimensional imaging provides caregivers with a unique ability to assess changes in valve function after mitral valve repair. Copyright © 2014 Elsevier Inc. All rights reserved.

Nanostructural evolution from nanosheets to one-dimensional nanoparticles for manganese oxide

International Nuclear Information System (INIS)

Pan, Hongmei; Kong, Xingang; Wen, Puhong; Kitayama, Tomonori; Feng, Qi

2012-01-01

Highlights: ► Nanosheets were transformed to other one-dimensional nanoparticles. ► Nanofibers, nanotubes, nanoribbons, and nanobelts were obtained. ► Nanoparticle morphology can be controlled with organic amines. ► Organic amines act as morphology directing agent. -- Abstract: This paper introduces a novel hydrothermal soft chemical synthesis process for manganese oxide nanostructured particles using two-dimensional manganese oxide nanosheets as precursor. In this process, a birnessite-type manganese oxide with a layered structure was exfoliated into its elementary layer nanosheets, and then the nanosheets were hydrothermally treated to transform the two-dimensional morphology of the nanosheets to one-dimensional nanoparticles. The manganese oxide nanofibers, nanotubes, nanobelts, nanoribbons, and fabric-ribbon-like particles constructed from nanofibers or nanobelts were obtained using this hydrothermal soft chemical process. The nanostructural evolution from the two-dimensional nanosheets to the one-dimensional nanoparticles was characterized by XRD, SEM, TEM, and TG-DTA analysis. The morphology and nanostructure of the products are strongly dependent on the molecular dimension of organic amine cations added in the reaction system. The organic amine cations act as a morphology directing agent in the nanostructural evolution process.

Foundations of the theory of three-dimensional quadrupolar mass spectrometry. 1

International Nuclear Information System (INIS)

Sheretov, Eh.P.

1979-01-01

The basic principles of the theory of three-dimensional quadrupolar mass spectrometry are developed. It is shown that the ''stretching'' of the electrode system of the sensor of a three-dimensional quadrupolar mass spectrometer in the direction of an axis (introduction of the system assymetry) leads to a sharp decrease of the high-frequency field effect on the particle trajectory in this direction. Presented are ratios determining the configuration of electrode systems of sensors of flight-type quadrupolar mass spectrometers. Specific features of the stability diagram for such analyzers are discussed. It is shown that the property detected makes it possible to develop new promising time-of-flight three-dimensional quadrupolar mass spectrometers

Three dimensional modelling of grain boundary interaction and evolution during directional solidification of multi-crystalline silicon

Science.gov (United States)

Jain, T.; Lin, H. K.; Lan, C. W.

2018-03-01

The development of grain structures during directional solidification of multi-crystalline silicon (mc-Si) plays a crucial role in the materials quality for silicon solar cells. Three dimensional (3D) modelling of the grain boundary (GB) interaction and evolution based on phase fields by considering anisotropic GB energy and mobility for mc-Si is carried out for the first time to elucidate the process. The energy and mobility of GBs are allowed to depend on misorientation and the GB plane. To examine the correctness of our method, the known the coincident site lattice (CSL) combinations such as (∑ a + ∑ b → ∑ a × b) or (∑ a + ∑ b → ∑ a / b) are verified. We frther discuss how to use the GB normal to characterize a ∑ 3 twin GB into a tilt or a twist one, and show the interaction between tilt and twist ∑ 3 twin GBs. Two experimental scenarios are considered for comparison and the results are in good agreement with the experiments as well as the theoretical predictions.

The use of total human bone marrow fraction in a direct three-dimensional expansion approach for bone tissue engineering applications: focus on angiogenesis and osteogenesis.

Science.gov (United States)

Guerrero, Julien; Oliveira, Hugo; Catros, Sylvain; Siadous, Robin; Derkaoui, Sidi-Mohammed; Bareille, Reine; Letourneur, Didier; Amédée, Joëlle

2015-03-01

Current approaches in bone tissue engineering have shown limited success, mostly owing to insufficient vascularization of the construct. A common approach consists of co-culture of endothelial cells and osteoblastic cells. This strategy uses cells from different sources and differentiation states, thus increasing the complexity upstream of a clinical application. The source of reparative cells is paramount for the success of bone tissue engineering applications. In this context, stem cells obtained from human bone marrow hold much promise. Here, we analyzed the potential of human whole bone marrow cells directly expanded in a three-dimensional (3D) polymer matrix and focused on the further characterization of this heterogeneous population and on their ability to promote angiogenesis and osteogenesis, both in vitro and in vivo, in a subcutaneous model. Cellular aggregates were formed within 24 h and over the 12-day culture period expressed endothelial and bone-specific markers and a specific junctional protein. Ectopic implantation of the tissue-engineered constructs revealed osteoid tissue and vessel formation both at the periphery and within the implant. This work sheds light on the potential clinical use of human whole bone marrow for bone regeneration strategies, focusing on a simplified approach to develop a direct 3D culture without two-dimensional isolation or expansion.

Curvature perturbations from dimensional decoupling

CERN Document Server

Giovannini, Massimo

2005-01-01

The scalar modes of the geometry induced by dimensional decoupling are investigated. In the context of the low energy string effective action, solutions can be found where the spatial part of the background geometry is the direct product of two maximally symmetric Euclidean manifolds whose related scale factors evolve at a dual rate so that the expanding dimensions first accelerate and then decelerate while the internal dimensions always contract. After introducing the perturbative treatment of the inhomogeneities, a class of five-dimensional geometries is discussed in detail. Quasi-normal modes of the system are derived and the numerical solution for the evolution of the metric inhomogeneities shows that the fluctuations of the internal dimensions provide a term that can be interpreted, in analogy with the well-known four-dimensional situation, as a non-adiabatic pressure density variation. Implications of this result are discussed with particular attention to string cosmological scenarios.

Three-dimensional metamaterials fabricated using Proton Beam Writing

Energy Technology Data Exchange (ETDEWEB)

Bettiol, A.A., E-mail: a.bettiol@nus.edu.sg [Centre for Ion Beam Applications, Department of Physics, National University of Singapore, 2 Science Dr. 3, Singapore 117542 (Singapore); Turaga, S.P.; Yan, Y.; Vanga, S.K. [Centre for Ion Beam Applications, Department of Physics, National University of Singapore, 2 Science Dr. 3, Singapore 117542 (Singapore); Chiam, S.Y. [NUS High School for Maths and Science, 20 Clementi Avenue 1, Singapore 129957 (Singapore)

2013-07-01

Proton Beam Writing (PBW) is a direct write lithographic technique that has recently been applied to the fabrication of three dimensional metamaterials. In this work, we show that the unique capabilities of PBW, namely the ability to fabricate arrays of high resolution, high aspect ratio microstructures in polymer or replicated into metal, is well suited to metamaterials research. We have also developed a novel method for selectively electroless plating silver directly onto polymer structures that were fabricated using PBW. This method opens up new avenues for utilizing PBW for making metamaterials and other sub-wavelength metallic structures. Several potential applications of three dimensional metamaterials fabricated using PBW are discussed, including sensing and negative refractive index materials.

Opportunities and challenges for direct C–H functionalization of piperazines

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Zhishi Ye

2016-04-01

Full Text Available Piperazine ranks within the top three most utilized N-heterocyclic moieties in FDA-approved small-molecule pharmaceuticals. Herein we summarize the current synthetic methods available to perform C–H functionalization on piperazines in order to lend structural diversity to this privileged drug scaffold. Multiple approaches such as those involving α-lithiation trapping, transition-metal-catalyzed α-C–H functionalizations, and photoredox catalysis are discussed. We also highlight the difficulties experienced when successful methods for α-C–H functionalization of acyclic amines and saturated mono-nitrogen heterocyclic compounds (such as piperidines and pyrrolidines were applied to piperazine substrates.

Electromagnetic radiation reaction force and radiation potential in general five-dimensional relativity

International Nuclear Information System (INIS)

Lo, C.Y.; Goldstein, G.R.; Napier, A.

1989-01-01

A unified theory of electromagnetic and gravitational fields should modify classical electrodynamics to account for the radiation reaction force. A conjecture that the radiation reaction force and the Lorentz force should be distinct, but in unified forms, results in a five-dimensional unified theory of five variables. It is found that a semicylindrical condition can reconcile the apparent differences between a five-dimensional physical space and our four-dimensional perceptions. Analysis of the geodesic equations results in the notion of gauge dynamics which manifests the influence of the unrestricted fifth variable. The element g 55 of the five-dimensional metric is identified as the radiation potential, which can directly determine the radiation reaction force. This gives a distinct physical origin for the radiation process in classical theory. The potential suggests that the electron can have excited states in quantum electrodynamics. This theory is supported with calculations which demonstrate that the motion of the fifth variable directly causes physical changes in the four-dimensional subspace

Handwriting: three-dimensional kinetic synergies in circle drawing movements.

Science.gov (United States)

Hooke, Alexander W; Karol, Sohit; Park, Jaebum; Kim, Yoon Hyuk; Shim, Jae Kun

2012-07-01

The purpose of this study was to investigate central nervous system (CNS) strategies for controlling multifinger forces during a circle-drawing task. Subjects drew 30 concentric, discontinuous clockwise and counter clockwise circles, at self and experimenter-set paces. The three-dimensional trajectory of the pen's center of mass and the three-dimensional forces and moments of force at each contact between the hand and the pen were recorded. Uncontrolled Manifold Analysis was used to quantify the synergies between pen-hand contact forces in radial, tangential and vertical directions. Results showed that synergies in the radial and tangential components were significantly stronger than in the vertical component. Synergies in the clockwise direction were significantly stronger than the counterclockwise direction in the radial and vertical components. Pace was found to be insignificant under any condition.

Development of sodium droplet combustion analysis methodology using direct numerical simulation in 3-dimensional coordinate (COMET)

International Nuclear Information System (INIS)

Okano, Yasushi; Ohira, Hiroaki

1998-08-01

In the early stage of sodium leak event of liquid metal fast breeder reactor, LMFBR, liquid sodium flows out from a piping, and ignition and combustion of liquid sodium droplet might occur under certain environmental condition. Compressible forced air flow, diffusion of chemical species, liquid sodium droplet behavior, chemical reactions and thermodynamic properties should be evaluated with considering physical dependence and numerical connection among them for analyzing combustion of sodium liquid droplet. A direct numerical simulation code was developed for numerical analysis of sodium liquid droplet in forced convection air flow. The numerical code named COMET, 'Sodium Droplet COmbustion Analysis METhodology using Direct Numerical Simulation in 3-Dimensional Coordinate'. The extended MAC method was used to calculate compressible forced air flow. Counter diffusion among chemical species is also calculated. Transport models of mass and energy between droplet and surrounding atmospheric air were developed. Equation-solving methods were used for computing multiphase equilibrium between sodium and air. Thermodynamic properties of chemical species were evaluated using dynamic theory of gases. Combustion of single sphere liquid sodium droplet in forced convection, constant velocity, uniform air flow was numerically simulated using COMET. Change of droplet diameter with time was closely agree with d 2 -law of droplet combustion theory. Spatial distributions of combustion rate and heat generation and formation, decomposition and movement of chemical species were analyzed. Quantitative calculations of heat generation and chemical species formation in spray combustion are enabled for various kinds of environmental condition by simulating liquid sodium droplet combustion using COMET. (author)

Cohesive Motion Control Algorithm for Formation of Multiple Autonomous Agents

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Debabrata Atta

2010-01-01

Full Text Available This paper presents a motion control strategy for a rigid and constraint consistent formation that can be modeled by a directed graph whose each vertex represents individual agent kinematics and each of directed edges represents distance constraints maintained by an agent, called follower, to its neighbouring agent. A rigid and constraint consistent graph is called persistent graph. A persistent graph is minimally persistent if it is persistent, and no edge can be removed without losing its persistence. An acyclic (free of cycles in its sensing pattern minimally persistent graph of Leader-Follower structure has been considered here which can be constructed from an initial Leader-Follower seed (initial graph with two vertices, one is Leader and another one is First Follower and one edge in between them is directed towards Leader by Henneberg sequence (a procedure of growing a graph containing only vertex additions. A set of nonlinear optimization-based decentralized control laws for mobile autonomous point agents in two dimensional plane have been proposed. An infinitesimal deviation in formation shape created continuous motion of Leader is compensated by corresponding continuous motion of other agents fulfilling the shortest path criteria.

A measurement system for two-dimensional DC-biased properties of magnetic materials

International Nuclear Information System (INIS)

Enokizono, M.; Matsuo, H.

2003-01-01

So far, the DC-biased magnetic properties have been measured in one dimension (scalar). However, these scalar magnetic properties are not enough to clarify the DC-biased magnetic properties because the scalar magnetic properties cannot exactly take into account the phase difference between the magnetic flux density B vector and the magnetic filed strength H vector. Thus, the magnetic field strength H and magnetic flux density B in magnetic materials must be measured as vector quantities (two-dimensional), directly. We showed the measurement system using a single-sheet tester (SST) to clarify the two-dimensional DC-biased magnetic properties. This system excited AC in Y-direction and DC in X-direction. This paper shows the measurement system using an SST and presents the measurement results of two-dimensional DC-biased magnetic properties when changing the DC exciting voltage and the iron loss

Dynamics of two-dimensional solitary vortices in a low-β plasma with convective motion

International Nuclear Information System (INIS)

Makino, Mitsuhiro; Kamimura, Tetsuo; Taniuti, Tosiya.

1980-12-01

Numerical studies of the Hasegawa-Mima equation, derived in the context of drift waves but equivalent to the quasigeostrophic vortex potential equation for Rossby waves, show the stable properties of solitary vortices which are two dimensional, localized, steady and translating solutions of this same equation. A solitary vortex can propagate only in the direction (x-direction) perpendicular to the density gradient. When this solitary vortex solution is inclined at some angle with respect to the x-axis, its propagation direction oscillates in the x and y plane. In two dimensional collisions, i.e. head-on collision and overtaking, solitary vortices interact two-dimensionally and recover their initial shapes at the end of both types of collisions. (author)

Noise-induced drift in two-dimensional anisotropic systems

Science.gov (United States)

Farago, Oded

2017-10-01

We study the isothermal Brownian dynamics of a particle in a system with spatially varying diffusivity. Due to the heterogeneity of the system, the particle's mean displacement does not vanish even if it does not experience any physical force. This phenomenon has been termed "noise-induced drift," and has been extensively studied for one-dimensional systems. Here, we examine the noise-induced drift in a two-dimensional anisotropic system, characterized by a symmetric diffusion tensor with unequal diagonal elements. A general expression for the mean displacement vector is derived and presented as a sum of two vectors, depicting two distinct drifting effects. The first vector describes the tendency of the particle to drift toward the high diffusivity side in each orthogonal principal diffusion direction. This is a generalization of the well-known expression for the noise-induced drift in one-dimensional systems. The second vector represents a novel drifting effect, not found in one-dimensional systems, originating from the spatial rotation in the directions of the principal axes. The validity of the derived expressions is verified by using Langevin dynamics simulations. As a specific example, we consider the relative diffusion of two transmembrane proteins, and demonstrate that the average distance between them increases at a surprisingly fast rate of several tens of micrometers per second.

Development of a 3-dimensional seismic isolation floor for computer systems

International Nuclear Information System (INIS)

Kurihara, M.; Shigeta, M.; Nino, T.; Matsuki, T.

1991-01-01

In this paper, we investigated the applicability of a seismic isolation floor as a method for protecting computer systems from strong earthquakes, such as computer systems in nuclear power plants. Assuming that the computer system is guaranteed for 250 cm/s 2 of input acceleration in the horizontal and vertical directions as the seismic performance, the basic design specification of the seismic isolation floor is considered as follows. Against S 1 level earthquakes, the maximum acceleration response of the seismic isolation floor in the horizontal and vertical directions is kept less than 250 cm/s 2 to maintain continuous computer operation. Against S 2 level earthquakes, the isolation floor allows large horizontal movement and large displacement of the isolation devices to reduce the acceleration response, although it is not guaranteed to be less than 250 cm/s 2 . By reducing the acceleration response, however, serious damage to the computer systems is reduced, so that they can be restarted after an earthquake. Usually, seismic isolation floor systems permit 2-dimensional (horizontal) isolation. However, in the case of just-under-seated earthquakes, which have large vertical components, the vertical acceleration response of this system is amplified by the lateral vibration of the frame of the isolation floor. Therefore, in this study a 3-dimensional seismic isolation floor, including vertical isolation, was developed. This paper describes 1) the experimental results of the response characteristics of the 3-dimensional seismic isolation floor built as a trial using a 3-dimensional shaking table, and 2) comparison of a 2-dimensional analytical model, for motion in one horizontal direction and the vertical direction, to experimental results. (J.P.N.)

Macro- and micro-designed chitosan-alginate scaffold architecture by three-dimensional printing and directional freezing

International Nuclear Information System (INIS)

Reed, Stephanie; Wu, Benjamin M; Lau, Grace; Delattre, Benjamin; Lopez, David Don; Tomsia, Antoni P

2016-01-01

While many tissue-engineered constructs aim to treat cartilage defects, most involve chondrocyte or stem cell seeding on scaffolds. The clinical application of cell-based techniques is limited due to the cost of maintaining cellular constructs on the shelf, potential immune response to allogeneic cell lines, and autologous chondrocyte sources requiring biopsy from already diseased or injured, scarce tissue. An acellular scaffold that can induce endogenous influx and homogeneous distribution of native stem cells from bone marrow holds great promise for cartilage regeneration. This study aims to develop such an acellular scaffold using designed, channeled architecture that simultaneously models the native zones of articular cartilage and subchondral bone. Highly porous, hydrophilic chitosan-alginate (Ch-Al) scaffolds were fabricated in three-dimensionally printed (3DP) molds designed to create millimeter scale macro-channels. Different polymer preform casting techniques were employed to produce scaffolds from both negative and positive 3DP molds. Macro-channeled scaffolds improved cell suspension distribution and uptake overly randomly porous scaffolds, with a wicking volumetric flow rate of 445.6 ± 30.3 mm 3 s −1 for aqueous solutions and 177 ± 16 mm 3 s −1 for blood. Additionally, directional freezing was applied to Ch-Al scaffolds, resulting in lamellar pores measuring 300 μm and 50 μm on the long and short axes, thus creating micrometer scale micro-channels. After directionally freezing Ch-Al solution cast in 3DP molds, the combined macro- and micro-channeled scaffold architecture enhanced cell suspension uptake beyond either macro- or micro-channels alone, reaching a volumetric flow rate of 1782.1 ± 48 mm 3 s −1 for aqueous solutions and 440.9 ± 0.5 mm 3 s −1 for blood. By combining 3DP and directional freezing, we can control the micro- and macro-architecture of Ch-Al to drastically improve cell influx into and distribution within the

Bayesian networks and food security - An introduction

NARCIS (Netherlands)

Stein, A.

2004-01-01

This paper gives an introduction to Bayesian networks. Networks are defined and put into a Bayesian context. Directed acyclical graphs play a crucial role here. Two simple examples from food security are addressed. Possible uses of Bayesian networks for implementation and further use in decision

DAG-based attack and defense modeling: don’t miss the forest for the attack trees

NARCIS (Netherlands)

Kordy, Barbara; Piètre-Cambacédès, Ludovic; Schweitzer, Patrick

2015-01-01

This paper presents the current state of the art on attack and defense modeling approaches that are based on directed acyclic graphs (DAGs). DAGs allow for a hierarchical decomposition of complex scenarios into simple, easily understandable and quantifiable actions. Methods based on threat trees and

Three-directional motion compensation-based novel-look-up-table for video hologram generation of three-dimensional objects freely maneuvering in space.

Science.gov (United States)

Dong, Xiao-Bin; Kim, Seung-Cheol; Kim, Eun-Soo

2014-07-14

A new three-directional motion compensation-based novel-look-up-table (3DMC-NLUT) based on its shift-invariance and thin-lens properties, is proposed for video hologram generation of three-dimensional (3-D) objects moving with large depth variations in space. The input 3-D video frames are grouped into a set of eight in sequence, where the first and remaining seven frames in each set become the reference frame (RF) and general frames (GFs), respectively. Hence, each 3-D video frame is segmented into a set of depth-sliced object images (DOIs). Then x, y, and z-directional motion vectors are estimated from blocks and DOIs between the RF and each of the GFs, respectively. With these motion vectors, object motions in space are compensated. Then, only the difference images between the 3-directionally motion-compensated RF and each of the GFs are applied to the NLUT for hologram calculation. Experimental results reveal that the average number of calculated object points and the average calculation time of the proposed method have been reduced compared to those of the conventional NLUT, TR-NLUT and MPEG-NLUT by 38.14%, 69.48%, and 67.41% and 35.30%, 66.39%, and 64.46%, respectively.

Direct numerical simulation of human phonation

Science.gov (United States)

Bodony, Daniel; Saurabh, Shakti

2017-11-01

The generation and propagation of the human voice in three-dimensions is studied using direct numerical simulation. A full body domain is employed for the purpose of directly computing the sound in the region past the speaker's mouth. The air in the vocal tract is modeled as a compressible and viscous fluid interacting with the elastic vocal folds. The vocal fold tissue material properties are multi-layered, with varying stiffness, and a linear elastic transversely isotropic model is utilized and implemented in a quadratic finite element code. The fluid-solid domains are coupled through a boundary-fitted interface and utilize a Poisson equation-based mesh deformation method. A kinematic constraint based on a specified minimum gap between the vocal folds is applied to prevent collision during glottal closure. Both near VF flow dynamics and far-field acoustics have been studied. A comparison is drawn to current two-dimensional simulations as well as to data from the literature. Near field vocal fold dynamics and glottal flow results are studied and in good agreement with previous three-dimensional phonation studies. Far-field acoustic characteristics, when compared to their two-dimensional counterpart, are shown to be sensitive to the dimensionality. Supported by the National Science Foundation (CAREER Award Number 1150439).

Quantum Communication Through a Two-Dimensional Spin Network

International Nuclear Information System (INIS)

Wang Zhaoming; Gu Yongjian

2012-01-01

We investigate the state or entanglement transfer through a two-dimensional spin network. We show that for state transfer, better fidelity can be gained along the diagonal direction but for entanglement transfer, when the initial entanglement is created along the boundary, the concurrence is more inclined to propagate along the boundary. This behavior is produced by quantum mechanical interference and the communication quality depends on the precise size of the network. For some number of sites, the fidelity in a two-dimensional channel is higher than one-dimensional case. This is an important result for realizing quantum communication through high dimension spin chain networks.

HIGH DIMENSIONAL COVARIANCE MATRIX ESTIMATION IN APPROXIMATE FACTOR MODELS.

Science.gov (United States)

Fan, Jianqing; Liao, Yuan; Mincheva, Martina

2011-01-01

The variance covariance matrix plays a central role in the inferential theories of high dimensional factor models in finance and economics. Popular regularization methods of directly exploiting sparsity are not directly applicable to many financial problems. Classical methods of estimating the covariance matrices are based on the strict factor models, assuming independent idiosyncratic components. This assumption, however, is restrictive in practical applications. By assuming sparse error covariance matrix, we allow the presence of the cross-sectional correlation even after taking out common factors, and it enables us to combine the merits of both methods. We estimate the sparse covariance using the adaptive thresholding technique as in Cai and Liu (2011), taking into account the fact that direct observations of the idiosyncratic components are unavailable. The impact of high dimensionality on the covariance matrix estimation based on the factor structure is then studied.

A retrospective and prospective survey of three-dimensional transport calculations

International Nuclear Information System (INIS)

Nakahara, Yasuaki

1985-01-01

A retrospective survey is made on the three-dimensional radiation transport calculations. Introduction is given to computer codes based on the distinctive numerical methods such as the Monte Carlo, Direct Integration, Ssub(n) and Finite Element Methods to solve the three-dimensional transport equations. Prospective discussions are made on pros and cons of these methods. (author)

A Direct Algorithm Maple Package of One-Dimensional Optimal System for Group Invariant Solutions

Science.gov (United States)

Zhang, Lin; Han, Zhong; Chen, Yong

2018-01-01

To construct the one-dimensional optimal system of finite dimensional Lie algebra automatically, we develop a new Maple package One Optimal System. Meanwhile, we propose a new method to calculate the adjoint transformation matrix and find all the invariants of Lie algebra in spite of Killing form checking possible constraints of each classification. Besides, a new conception called invariance set is raised. Moreover, this Maple package is proved to be more efficiency and precise than before by applying it to some classic examples. Supported by the Global Change Research Program of China under Grant No. 2015CB95390, National Natural Science Foundation of China under Grant Nos. 11675054 and 11435005, and Shanghai Collaborative Innovation Center of Trustworthy Software for Internet of Things under Grant No. ZF1213

Development of spectral history methods for pin-by-pin core analysis method using three-dimensional direct response matrix

International Nuclear Information System (INIS)

Mitsuyasu, T.; Ishii, K.; Hino, T.; Aoyama, M.

2009-01-01

Spectral history methods for pin-by-pin core analysis method using the three-dimensional direct response matrix have been developed. The direct response matrix is formalized by four sub-response matrices in order to respond to a core eigenvalue k and thus can be recomposed at each outer iteration in the core analysis. For core analysis, it is necessary to take into account the burn-up effect related to spectral history. One of the methods is to evaluate the nodal burn-up spectrum obtained using the out-going neutron current. The other is to correct the fuel rod neutron production rates obtained the pin-by-pin correction. These spectral history methods were tested in a heterogeneous system. The test results show that the neutron multiplication factor error can be reduced by half during burn-up, the nodal neutron production rates errors can be reduced by 30% or more. The root-mean-square differences between the relative fuel rod neutron production rate distributions can be reduced within 1.1% error. This means that these methods can accurately reflect the effects of intra- and inter-assembly heterogeneities during burn-up and can be used for core analysis. Core analysis with the DRM method was carried out for an ABWR quarter core and it was found that both thermal power and coolant-flow distributions were smoothly converged. (authors)

Rhodium-catalysed syn-carboamination of alkenes via a transient directing group.

Science.gov (United States)

Piou, Tiffany; Rovis, Tomislav

2015-11-05

Alkenes are the most ubiquitous prochiral functional groups--those that can be converted from achiral to chiral in a single step--that are accessible to synthetic chemists. For this reason, difunctionalization reactions of alkenes (whereby two functional groups are added to the same double bond) are particularly important, as they can be used to produce highly complex molecular architectures. Stereoselective oxidation reactions, including dihydroxylation, aminohydroxylation and halogenation, are well established methods for functionalizing alkenes. However, the intermolecular incorporation of both carbon- and nitrogen-based functionalities stereoselectively across an alkene has not been reported. Here we describe the rhodium-catalysed carboamination of alkenes at the same (syn) face of a double bond, initiated by a carbon-hydrogen activation event that uses enoxyphthalimides as the source of both the carbon and the nitrogen functionalities. The reaction methodology allows for the intermolecular, stereospecific formation of one carbon-carbon and one carbon-nitrogen bond across an alkene, which is, to our knowledge, unprecedented. The reaction design involves the in situ generation of a bidentate directing group and the use of a new cyclopentadienyl ligand to control the reactivity of rhodium. The results provide a new way of synthesizing functionalized alkenes, and should lead to the convergent and stereoselective assembly of amine-containing acyclic molecules.

Can we believe the DAGs?

DEFF Research Database (Denmark)

Aalen, O. O.; Røysland, K.; Gran, J. M.

2016-01-01

Directed acyclic graphs (DAGs) play a large role in the modern approach to causal inference. DAGs describe the relationship between measurements taken at various discrete times including the effect of interventions. The causal mechanisms, on the other hand, would naturally be assumed to be a cont...

Two-Dimensional Tellurene as Excellent Thermoelectric Material

KAUST Repository

Sharma, Sitansh; Singh, Nirpendra; Schwingenschlö gl, Udo

2018-01-01

We study the thermoelectric properties of two-dimensional tellurene by first-principles calculations and semiclassical Boltzmann transport theory. The HSE06 hybrid functional results in a moderate direct band gap of 1.48 eV at the Γ point. A high

A two-dimensional mathematical model of percutaneous drug absorption

Directory of Open Access Journals (Sweden)

Kubota K

2004-06-01

Full Text Available Abstract Background When a drug is applied on the skin surface, the concentration of the drug accumulated in the skin and the amount of the drug eliminated into the blood vessel depend on the value of a parameter, r. The values of r depend on the amount of diffusion and the normalized skin-capillary clearence. It is defined as the ratio of the steady-state drug concentration at the skin-capillary boundary to that at the skin-surface in one-dimensional models. The present paper studies the effect of the parameter values, when the region of contact of the skin with the drug, is a line segment on the skin surface. Methods Though a simple one-dimensional model is often useful to describe percutaneous drug absorption, it may be better represented by multi-dimensional models. A two-dimensional mathematical model is developed for percutaneous absorption of a drug, which may be used when the diffusion of the drug in the direction parallel to the skin surface must be examined, as well as in the direction into the skin, examined in one-dimensional models. This model consists of a linear second-order parabolic equation with appropriate initial conditions and boundary conditions. These boundary conditions are of Dirichlet type, Neumann type or Robin type. A finite-difference method which maintains second-order accuracy in space along the boundary, is developed to solve the parabolic equation. Extrapolation in time is applied to improve the accuracy in time. Solution of the parabolic equation gives the concentration of the drug in the skin at a given time. Results Simulation of the numerical methods described is carried out with various values of the parameter r. The illustrations are given in the form of figures. Conclusion Based on the values of r, conclusions are drawn about (1 the flow rate of the drug, (2 the flux and the cumulative amount of drug eliminated into the receptor cell, (3 the steady-state value of the flux, (4 the time to reach the steady

Velocity and Dispersion for a Two-Dimensional Random Walk

International Nuclear Information System (INIS)

Li Jinghui

2009-01-01

In the paper, we consider the transport of a two-dimensional random walk. The velocity and the dispersion of this two-dimensional random walk are derived. It mainly show that: (i) by controlling the values of the transition rates, the direction of the random walk can be reversed; (ii) for some suitably selected transition rates, our two-dimensional random walk can be efficient in comparison with the one-dimensional random walk. Our work is motivated in part by the challenge to explain the unidirectional transport of motor proteins. When the motor proteins move at the turn points of their tracks (i.e., the cytoskeleton filaments and the DNA molecular tubes), some of our results in this paper can be used to deal with the problem. (general)

Fabrication of three-dimensional polymer quadratic nonlinear grating structures by layer-by-layer direct laser writing technique

Science.gov (United States)

Bich Do, Danh; Lin, Jian Hung; Diep Lai, Ngoc; Kan, Hung-Chih; Hsu, Chia Chen

2011-08-01

We demonstrate the fabrication of a three-dimensional (3D) polymer quadratic nonlinear (χ(2)) grating structure. By performing layer-by-layer direct laser writing (DLW) and spin-coating approaches, desired photobleached grating patterns were embedded in the guest--host dispersed-red-1/poly(methylmethacrylate) (DR1/PMMA) active layers of an active-passive alternative multilayer structure through photobleaching of DR1 molecules. Polyvinyl-alcohol and SU8 thin films were deposited between DR1/PMMA layers serving as a passive layer to separate DR1/PMMA active layers. After applying the corona electric field poling to the multilayer structure, nonbleached DR1 molecules in the active layers formed polar distribution, and a 3D χ(2) grating structure was obtained. The χ(2) grating structures at different DR1/PMMA nonlinear layers were mapped by laser scanning second harmonic (SH) microscopy, and no cross talk was observed between SH images obtained from neighboring nonlinear layers. The layer-by-layer DLW technique is favorable to fabricating hierarchical 3D polymer nonlinear structures for optoelectronic applications with flexible structural design.

Peretinoin, an acyclic retinoid, improves the hepatic gene signature of chronic hepatitis C following curative therapy of hepatocellular carcinoma

International Nuclear Information System (INIS)

Honda, Masao; Yamashita, Taro; Yamashita, Tatsuya; Arai, Kuniaki; Sakai, Yoshio; Sakai, Akito; Nakamura, Mikiko; Mizukoshi, Eishiro; Kaneko, Shuichi

2013-01-01

The acyclic retinoid, peretinoin, has been shown to be effective for suppressing hepatocellular carcinoma (HCC) recurrence after definitive treatment in a small-scale randomized clinical trial. However, little has been documented about the mechanism by which peretinoin exerts its inhibitory effects against recurrent HCC in humans in vivo. Twelve hepatitis C virus-positive patients whose HCC had been eradicated through curative resection or ablation underwent liver biopsy at baseline and week 8 of treatment with either a daily dose of 300 or 600 mg peretinoin. RNA isolated from biopsy samples was subjected to gene expression profile analysis. Peretinoin treatment elevated the expression levels of IGFBP6, RBP1, PRB4, CEBPA, G0S2, TGM2, GPRC5A, CYP26B1, and many other retinoid target genes. Elevated expression was also observed for interferon-, Wnt-, and tumor suppressor-related genes. By contrast, decreased expression levels were found for mTOR- and tumor progression-related genes. Interestingly, gene expression profiles for week 8 of peretinoin treatment could be classified into two groups of recurrence and non-recurrence with a prediction accuracy rate of 79.6% (P<0.05). In the liver of patients with non-recurrence, expression of PDGFC and other angiogenesis genes, cancer stem cell marker genes, and genes related to tumor progression was down-regulated, while expression of genes related to hepatocyte differentiation, tumor suppression genes, and other genes related to apoptosis induction was up-regulated. Gene expression profiling at week 8 of peretinoin treatment could successfully predict HCC recurrence within 2 years. This study is the first to show the effect of peretinoin in suppressing HCC recurrence in vivo based on gene expression profiles and provides a molecular basis for understanding the efficacy of peretinoin

Multi-dimensional modelling of spray, in-cylinder air motion and fuel

Indian Academy of Sciences (India)

In this work, three-dimensional fuel–air mixing inside a conventional spark ignition engine cylinder is simulated under direct injection conditions. The motivation is to explore retrofitting of conventional engines for direct injection to take advantage of low emissions and high thermal efficiency of the direct injection concept.

Computerized three-dimensional normal atlas

International Nuclear Information System (INIS)

Mano, Isamu; Suto, Yasuzo; Suzuki, Masataka; Iio, Masahiro.

1990-01-01

This paper presents our ongoing project in which normal human anatomy and its quantitative data are systematically arranged in a computer. The final product, the Computerized Three-Dimensional Normal Atlas, will be able to supply tomographic images in any direction, 3-D images, and coded information on organs, e.g., anatomical names, CT numbers, and T 1 and T 2 values. (author)

Infinite-dimensional Z2sup(k)-supermanifolds

International Nuclear Information System (INIS)

Molotkov, V.

1984-10-01

In this paper the theory of finite-dimensional supermanifolds of Berezin, Leites and Kostant is generalized in two directions. First, we introduce infinite-dimensional supermanifolds ''locally isomorphic'' to arbitrary Banach (or, more generally, locally convex) superspaces. This is achieved by considering supermanifolds as functors (equipped with some additional structure) from the category of finite-dimensional Grassman superalgebras into the category of the corresponding smooth manifolds (Banach or locally convex). As examples, flag supermanifolds of Banach superspaces as well as unitary supergroups of Hilbert superspaces are constructed. Second, we define ''generalized'' supermanifolds, graded by Abelian groups Z 2 sup(k), instead of the group Z 2 (Z 2 sup(k)-supermanifolds). The corresponding superfields, describing, potentially, particles with more general statistics than Bose + Fermi, generally speaking, turn out to have an infinite number of components. (author)

Surface representations of two- and three-dimensional fluid flow topology

Science.gov (United States)

Helman, James L.; Hesselink, Lambertus

1990-01-01

We discuss our work using critical point analysis to generate representations of the vector field topology of numerical flow data sets. Critical points are located and characterized in a two-dimensional domain, which may be either a two-dimensional flow field or the tangential velocity field near a three-dimensional body. Tangent curves are then integrated out along the principal directions of certain classes of critical points. The points and curves are linked to form a skeleton representing the two-dimensional vector field topology. When generated from the tangential velocity field near a body in a three-dimensional flow, the skeleton includes the critical points and curves which provide a basis for analyzing the three-dimensional structure of the flow separation. The points along the separation curves in the skeleton are used to start tangent curve integrations to generate surfaces representing the topology of the associated flow separations.

Edge Epitaxy of Two-dimensional MoSe2 and MoS2 Nanosheets on One-dimensional Nanowires

KAUST Repository

Chen, Junze; Wu, Xue-Jun; Gong, Yue; Zhu, Yihan; Yang, Zhenzhong; Li, Bing; Lu, Qipeng; Yu, Yifu; Han, Shikui; Zhang, Zhicheng; Zong, Yun; Han, Yu; Gu, Lin; Zhang, Hua

2017-01-01

the longitudinal direction of one-dimensional (1D) Cu2-xS nanowires (NWs) in an epitaxial manner. The obtained Cu2-xS-TMD heterostructures with tunable loading amount and lateral size of TMD NSs are achieved by the consecutive growth of TMD NSs on Cu2-xS NWs

Direct cooled power electronics substrate

Science.gov (United States)

Wiles, Randy H [Powell, TN; Wereszczak, Andrew A [Oak Ridge, TN; Ayers, Curtis W [Kingston, TN; Lowe, Kirk T [Knoxville, TN

2010-09-14

The disclosure describes directly cooling a three-dimensional, direct metallization (DM) layer in a power electronics device. To enable sufficient cooling, coolant flow channels are formed within the ceramic substrate. The direct metallization layer (typically copper) may be bonded to the ceramic substrate, and semiconductor chips (such as IGBT and diodes) may be soldered or sintered onto the direct metallization layer to form a power electronics module. Multiple modules may be attached to cooling headers that provide in-flow and out-flow of coolant through the channels in the ceramic substrate. The modules and cooling header assembly are preferably sized to fit inside the core of a toroidal shaped capacitor.

Concentric artificial impedance surface for directional sound beamforming

Directory of Open Access Journals (Sweden)

Kyungjun Song

2017-03-01

Full Text Available Utilizing acoustic metasurfaces consisting of subwavelength resonant textures, we design an artificial impedance surface by creating a new boundary condition. We demonstrate a circular artificial impedance surface with surface impedance modulation for directional sound beamforming in three-dimensional space. This artificial impedance surface is implemented by revolving two-dimensional Helmholtz resonators with varying internal coiled path. Physically, the textured surface has inductive surface impedance on its inner circular patterns and capacitive surface impedance on its outer circular patterns. Directional receive beamforming can be achieved using an omnidirectional microphone located at the focal point formed by the gradient-impeding surface. In addition, the uniaxial surface impedance patterning inside the circular aperture can be used for steering the direction of the main lobe of the radiation pattern.

The role of multidimensional instabilities in direct initiation of gaseous detonations in free space

KAUST Repository

Shen, Hua

2017-01-20

We numerically investigate the direct initiation of detonations driven by the propagation of a blast wave into a unconfined gaseous combustible mixture to study the role played by multidimensional instabilities in direct initiation of stable and unstable detonations. To this end, we first model the dynamics of unsteady propagation of detonation using the one-dimensional compressible Euler equations with a one-step chemical reaction model and cylindrical geometrical source terms. Subsequently, we use two-dimensional compressible Euler equations with just the chemical reaction source term to directly model cylindrical detonations. The one-dimensional results suggest that there are three regimes in the direct initiation for stable detonations, that the critical energy for mildly unstable detonations is not unique, and that highly unstable detonations are not self-sustainable. These phenomena agree well with one-dimensional theories and computations available in the literature. However, our two-dimensional results indicate that one-dimensional approaches are valid only for stable detonations. In mildly and highly unstable detonations, one-dimensional approaches break down because they cannot take the effects and interactions of multidimensional instabilities into account. In fact, instabilities generated in multidimensional settings yield the formation of strong transverse waves that, on one hand, increase the risk of failure of the detonation and, on the other hand, lead to the initiation of local over-driven detonations that enhance the overall self-sustainability of the global process. The competition between these two possible outcomes plays an important role in the direct initiation of detonations.

Modeling high dimensional multichannel brain signals

KAUST Repository

Hu, Lechuan

2017-03-27

In this paper, our goal is to model functional and effective (directional) connectivity in network of multichannel brain physiological signals (e.g., electroencephalograms, local field potentials). The primary challenges here are twofold: first, there are major statistical and computational difficulties for modeling and analyzing high dimensional multichannel brain signals; second, there is no set of universally-agreed measures for characterizing connectivity. To model multichannel brain signals, our approach is to fit a vector autoregressive (VAR) model with sufficiently high order so that complex lead-lag temporal dynamics between the channels can be accurately characterized. However, such a model contains a large number of parameters. Thus, we will estimate the high dimensional VAR parameter space by our proposed hybrid LASSLE method (LASSO+LSE) which is imposes regularization on the first step (to control for sparsity) and constrained least squares estimation on the second step (to improve bias and mean-squared error of the estimator). Then to characterize connectivity between channels in a brain network, we will use various measures but put an emphasis on partial directed coherence (PDC) in order to capture directional connectivity between channels. PDC is a directed frequency-specific measure that explains the extent to which the present oscillatory activity in a sender channel influences the future oscillatory activity in a specific receiver channel relative all possible receivers in the network. Using the proposed modeling approach, we have achieved some insights on learning in a rat engaged in a non-spatial memory task.

Modeling high dimensional multichannel brain signals

KAUST Repository

Hu, Lechuan; Fortin, Norbert; Ombao, Hernando

2017-01-01

In this paper, our goal is to model functional and effective (directional) connectivity in network of multichannel brain physiological signals (e.g., electroencephalograms, local field potentials). The primary challenges here are twofold: first, there are major statistical and computational difficulties for modeling and analyzing high dimensional multichannel brain signals; second, there is no set of universally-agreed measures for characterizing connectivity. To model multichannel brain signals, our approach is to fit a vector autoregressive (VAR) model with sufficiently high order so that complex lead-lag temporal dynamics between the channels can be accurately characterized. However, such a model contains a large number of parameters. Thus, we will estimate the high dimensional VAR parameter space by our proposed hybrid LASSLE method (LASSO+LSE) which is imposes regularization on the first step (to control for sparsity) and constrained least squares estimation on the second step (to improve bias and mean-squared error of the estimator). Then to characterize connectivity between channels in a brain network, we will use various measures but put an emphasis on partial directed coherence (PDC) in order to capture directional connectivity between channels. PDC is a directed frequency-specific measure that explains the extent to which the present oscillatory activity in a sender channel influences the future oscillatory activity in a specific receiver channel relative all possible receivers in the network. Using the proposed modeling approach, we have achieved some insights on learning in a rat engaged in a non-spatial memory task.

DataHigh: Graphical user interface for visualizing and interacting with high-dimensional neural activity

OpenAIRE

Cowley, Benjamin R.; Kaufman, Matthew T.; Churchland, Mark M.; Ryu, Stephen I.; Shenoy, Krishna V.; Yu, Byron M.

2012-01-01

The activity of tens to hundreds of neurons can be succinctly summarized by a smaller number of latent variables extracted using dimensionality reduction methods. These latent variables define a reduced-dimensional space in which we can study how population activity varies over time, across trials, and across experimental conditions. Ideally, we would like to visualize the population activity directly in the reduced-dimensional space, whose optimal dimensionality (as determined from the data)...

The one-dimensional transport codes MAKOKOT. Presentation and directions for use

International Nuclear Information System (INIS)

Capes, H.; Mercier, C.; Morera, J.P.

1986-06-01

In this note are presented the different one-dimensional evolution codes available to date under the generic name MAKOKOT. They are six principal codes: - TRANS: for ion and electron transport; -NEUTRE: for neutrals; -IMPUR: for impurities; -ECRH: for electron cyclotron resonance; -DENT: for sawtooth modelling and analysis; -BILAN: for global verification of conservation. One supplementary code is added which is an impurity evolution code; it takes in account, in 1-D geometry, the buffer zone generated by the limiter between the hot plasma and the wall. An abundant bibliography is given. A comprehensive manner of using is given which underlines the use versatility of these codes [fr

Oblique propagation of nonlinear hydromagnetic waves: One- and two-dimensional behavior

International Nuclear Information System (INIS)

Malara, F.; Elaoufir, J.

1991-01-01

The one- and two-dimensional behavior of obliquely propagating hydromagnetic waves is analyzed by means of analytical theory and numerical simulations. It is shown that the nonlinear evolution of a one-dimensional MHD wave leads to the formation of a rotational discontinuity and a compressive steepened quasi-linearly polarized pulse whose structure is similar to that of a finite amplitude magnetosonic simple wave. For small propagation angles, the pulse mode (fast or slow) depends on the value of β with respect to unity while for large propagation angles the wave mode is fixed by the sign of the initial density-field correlation. The two-dimensional evolution shows that an MHD wave is unstable against a small-amplitude long-wavelength modulation in the direction transverse to the wave propagation direction. A two-dimensional magnetosonic wave solution is found, in which the density fluctuation is driven by the corresponding total pressure fluctuation, exactly as in the one-dimensional simple wave. Along with the steepening effect, the wave experiences both wave front deformation and a self-focusing effect which may eventually lead to the collapse of the wave. The results compare well with observations of MHD waves in the Earth's foreshock and at comets

Three-dimensional construction and omni-directional rolling analysis of a novel frame-like lattice modular robot

Science.gov (United States)

Ding, Wan; Wu, Jianxu; Yao, Yan'an

2015-07-01

Lattice modular robots possess diversity actuation methods, such as electric telescopic rod, gear rack, magnet, robot arm, etc. The researches on lattice modular robots mainly focus on their hardware descriptions and reconfiguration algorithms. Meanwhile, their design architectures and actuation methods perform slow telescopic and moving speeds, relative low actuation force verse weight ratio, and without internal space to carry objects. To improve the mechanical performance and reveal the locomotion and reconfiguration binary essences of the lattice modular robots, a novel cube-shaped, frame-like, pneumatic-based reconfigurable robot module called pneumatic expandable cube(PE-Cube) is proposed. The three-dimensional(3D) expanding construction and omni-directional rolling analysis of the constructed robots are the main focuses. The PE-Cube with three degrees of freedom(DoFs) is assembled by replacing the twelve edges of a cube with pneumatic cylinders. The proposed symmetric construction condition makes the constructed robots possess the same properties in each supporting state, and a binary control strategy cooperated with binary actuator(pneumatic cylinder) is directly adopted to control the PE-Cube. Taking an eight PE-Cube modules' construction as example, its dynamic rolling simulation, static rolling condition, and turning gait are illustrated and discussed. To testify telescopic synchronization, respond speed, locomotion feasibility, and repeatability and reliability of hardware system, an experimental pneumatic-based robotic system is built and the rolling and turning experiments of the eight PE-Cube modules' construction are carried out. As an extension, the locomotion feasibility of a thirty-two PE-Cube modules' construction is analyzed and proved, including dynamic rolling simulation, static rolling condition, and dynamic analysis in free tipping process. The proposed PE-Cube module, construction method, and locomotion analysis enrich the family of the

Towards a three-dimensional framework of centrally regulated and goal-directed exercise behaviour: a narrative review.

Science.gov (United States)

Venhorst, Andreas; Micklewright, Dominic; Noakes, Timothy D

2017-08-23

The Central Governor Model (CGM) ignited a paradigm shift from concepts of catastrophic failure towards central regulation of exercise performance. However, the CGM has focused on the central integration of afferent feedback in homeostatic control. Accordingly, it neglected the important role of volitional self-regulatory control and the integration of affective components inherently attached to all physiological cues. Another limitation is the large reliance on the Gestalt phenomenon of perceived exertion. Thus, progress towards a comprehensive multidimensional model of perceived fatigability and exercise regulation is needed. Drawing on Gate Control Theory of pain, we propose a three-dimensional framework of centrally regulated and goal-directed exercise behaviour, which differentiates between sensory, affective and cognitive processes shaping the perceptual milieu during exercise. We propose that: (A) perceived mental strain and perceived physical strain are primary determinants of pacing behaviour reflecting sensory-discriminatory processes necessary to align planned behaviour with current physiological state, (B) core affect plays a primary and mediatory role in exercise and performance regulation, and its underlying two dimensions hedonicity and arousal reflect affective-motivational processes triggering approach and avoidance behaviour, and (C) the mindset-shift associated with an action crisis plays a primary role in volitional self-regulatory control reflecting cognitive-evaluative processes between further goal-pursuit and goal-disengagement. The proposed framework has the potential to enrich theory development in centrally regulated and goal-directed exercise behaviour by emphasising the multidimensional dynamic processes underpinning perceived fatigability and provides a practical outline for investigating the complex interplay between the psychophysiological determinants of pacing and performance during prolonged endurance exercise. © Article author

Markov chain Monte Carlo methods in directed graphical models

DEFF Research Database (Denmark)

Højbjerre, Malene

Directed graphical models present data possessing a complex dependence structure, and MCMC methods are computer-intensive simulation techniques to approximate high-dimensional intractable integrals, which emerge in such models with incomplete data. MCMC computations in directed graphical models h...

Free vibration analysis of multi directional functionally graded circular and annular plates

Energy Technology Data Exchange (ETDEWEB)

Kermani, Iman Davoodi; Ghayour, Mostafa; Mirdamadi, Hamid Reza [Isfahan Univ. of Technology, Isfahan (Iran, Islamic Republic of)

2012-11-15

This paper addresses the free vibration of multi directional functionally graded circular and annular plates using a semianalytical/numerical method, called state space based differential quadrature method. Three-dimensional elasticity equations are derived for multi directional functionally graded plates and a solution is given by the semi-analytical/numerical method. This method gives an analytical solution along the thickness direction, using a state space method and a numerical solution using differential quadrature method. Some numerical examples are presented to show the accuracy and convergence of the method. The most of simulations of the present study have been validated by the existing literature. The non dimensional frequencies and corresponding displacements mode shapes are obtained. Then the influences of thickness ratio and graded indexes are demonstrated on the non dimensional natural frequencies.

Method of dimensionality reduction in contact mechanics and friction

CERN Document Server

Popov, Valentin L

2015-01-01

This book describes for the first time a simulation method for the fast calculation of contact properties and friction between rough surfaces in a complete form. In contrast to existing simulation methods, the method of dimensionality reduction (MDR) is based on the exact mapping of various types of three-dimensional contact problems onto contacts of one-dimensional foundations. Within the confines of MDR, not only are three dimensional systems reduced to one-dimensional, but also the resulting degrees of freedom are independent from another. Therefore, MDR results in an enormous reduction of the development time for the numerical implementation of contact problems as well as the direct computation time and can ultimately assume a similar role in tribology as FEM has in structure mechanics or CFD methods, in hydrodynamics. Furthermore, it substantially simplifies analytical calculation and presents a sort of “pocket book edition” of the entirety contact mechanics. Measurements of the rheology of bodies in...

Flexible Acyclic Polyol-Chloride Anion Complexes and Their Characterization by Photoelectron Spectroscopy and Variable Temperature Binding Constant Determinations

Energy Technology Data Exchange (ETDEWEB)

Shokri, Alireza; Wang, Xue B.; Wang, Yangping; O' Doherty, George A.; Kass, Steven R.

2016-03-17

Flexible acyclic alcohols with 1–5 hydroxyl groups were bound to chloride anion and these complexes were interrogated by negative ion photoelectron spectroscopy and companion density functional theory computations. The resulting vertical detachment energies are reproduced on average to 0.10 eV by M06-2X/aug-cc-pVTZ predictions and range from 4.45 – 5.96 eV. These values are 0.84 – 2.35 eV larger than the adiabatic detachment energy of Cl– as a result of the larger hydrogen bond networks in the bigger polyols. Adiabatic detachment energies of the alcohol–Cl– clusters are more difficult to determine both experimentally and computationally. This is due to the large geometry changes that occur upon photodetachment and the large bond dissociation energy of H–Cl which enables the resulting chlorine atom to abstract a hydrogen from any of the methylene (CH2) or methine (CH) positions. Both ionic and non-ionic hydrogen bonds (i.e., OH•••Cl– and OH•••OH•••Cl–) form in the larger polyols complexes, and are found to be energetically comparable. Subtle structural differences, consequently can lead to the formation of different types of hydrogen bonds and maximizing the ionic ones is not always preferred. Solution equilibrium binding constants between the alcohols and tetrrabuylammonium chloride (TBACl) in acetonitrile at -24.2, 22.0, and 53.6 °C were also determined. The free energies of association are nearly identical for all of the substrates (i.e., ΔG° = -2.8 ± 0.7 kcal mol–1). Compensating enthalpy and entropy values reveal, contrary to expectation and the intrinsic gas-phase preferences, that the bigger systems with more hydroxyl groups are entropically favored and enthalpically disfavored relative to the smaller species. This suggests that more solvent molecules are released upon binding TBACl to alcohols with more hydroxyl groups and is consistent with the measured negative heat capacities. These quantities increase with

Execution spaces for simple higher dimensional automata

DEFF Research Database (Denmark)

Raussen, Martin

Higher Dimensional Automata (HDA) are highly expressive models for concurrency in Computer Science, cf van Glabbeek [26]. For a topologist, they are attractive since they can be modeled as cubical complexes - with an inbuilt restriction for directions´of allowable (d-)paths. In Raussen [25], we...

Comparative study on spreading function for directional wave spectra

Digital Repository Service at National Institute of Oceanography (India)

Bhat, S.S.; Anand, N.M.; Nayak, B.U.

-dimensional wave energy S(f) and the directional spreading function D(f, theta). This paper reviews various spreading functions proposed in the past for estimating the directional wave energy and presents their application to the Indian wave condition. It is found...

Flexible indexing of repetitive collections

DEFF Research Database (Denmark)

Belazzougui, Djamal; Cunial, Fabio; Gagie, Travis

2017-01-01

, at the cost of slower locate queries. Combining the RLBWT with the compact directed acyclic word graph answers locate queries for short patterns between four and ten times faster than a version of the run-length compressed suffix array (RLCSA) that uses comparable memory, and with very short patterns our...

Direct electrochemistry and electrocatalysis of hemoglobin at three-dimensional gold film electrode modified with self-assembled monolayers of 3-mercaptopropylphosphonic acid

International Nuclear Information System (INIS)

Chen Yu; Yang Xiaojing; Guo Lirong; Li Jing; Xia Xinghua; Zheng Limin

2009-01-01

Multilayered hemoglobin (Hb) molecules were successfully immobilized on three-dimensional gold film electrode modified with self-assembled monolayers (SAMs) of 3-mercaptopropylphosphonic acid. Direct electrochemistry of the immobilized multilayered Hb occurs with high thermal stability and electrochemical stability. In the multilayered Hb film, the most inner Hb molecules can directly transfer electron with the electrode, while the Hb protein beyond this layer communicates electron with the electrode via protein-protein electron exchange. In addition, the proposed functional interface can greatly enhance electron transfer rate of the immobilized Hb protein (k s = 15.8 ± 2.0 s -1 ) due to the increase of roughness of the gold substrate. Under optimized experimental conditions, the multilayered Hb film displays good bioelectrocatalytic activity toward the reduction of hydrogen peroxide. This electrochemical sensor shows fast response (less than 1 s), wide linear range (7.8 x 10 -8 to 9.1 x 10 -5 M) and low detection limit (2.5 x 10 -8 M), which can be attributed to good mass transport, large Hb proteins loading per unit area and fast electron transfer rate of Hb protein.

Apparent directional mass-transfer capacity coefficients in three-dimensional anisotropic heterogeneous aquifers under radial convergent transport

Science.gov (United States)

Pedretti, D.; Fernàndez-Garcia, D.; Sanchez-Vila, X.; Bolster, D.; Benson, D. A.

2014-02-01

Aquifer hydraulic properties such as hydraulic conductivity (K) are ubiquitously heterogeneous and typically only a statistical characterization can be sought. Additionally, statistical anisotropy at typical characterization scales is the rule. Thus, regardless of the processes governing solute transport at the local (pore) scale, transport becomes non-Fickian. Mass-transfer models provide an efficient tool that reproduces observed anomalous transport; in some cases though, these models lack predictability as model parameters cannot readily be connected to the physical properties of aquifers. In this study, we focus on a multirate mass-transfer model (MRMT), and in particular the apparent capacity coefficient (β), which is a strong indicator of the potential of immobile zones to capture moving solute. We aim to find if the choice of an apparent β can be phenomenologically related to measures of statistical anisotropy. We analyzed an ensemble of random simulations of three-dimensional log-transformed multi-Gaussian permeability fields with stationary anisotropic correlation under convergent flow conditions. It was found that apparent β also displays an anisotropic behavior, physically controlled by the aquifer directional connectivity, which in turn is controlled by the anisotropic correlation model. A high hydraulic connectivity results in large β values. These results provide new insights into the practical use of mass-transfer models for predictive purposes.

Three dimensional imaging technique for laser-plasma diagnostics

International Nuclear Information System (INIS)

Jiang Shaoen; Zheng Zhijian; Liu Zhongli

2001-01-01

A CT technique for laser-plasma diagnostic and a three-dimensional (3D) image reconstruction program (CT3D) have been developed. The 3D images of the laser-plasma are reconstructed by using a multiplication algebraic reconstruction technique (MART) from five pinhole camera images obtained along different sight directions. The technique has been used to measure the three-dimensional distribution of X-ray of laser-plasma experiments in Xingguang II device, and the good results are obtained. This shows that a CT technique can be applied to ICF experiments

Three dimensional imaging technique for laser-plasma diagnostics

Energy Technology Data Exchange (ETDEWEB)

Shaoen, Jiang; Zhijian, Zheng; Zhongli, Liu [China Academy of Engineering Physics, Chengdu (China)

2001-04-01

A CT technique for laser-plasma diagnostic and a three-dimensional (3D) image reconstruction program (CT3D) have been developed. The 3D images of the laser-plasma are reconstructed by using a multiplication algebraic reconstruction technique (MART) from five pinhole camera images obtained along different sight directions. The technique has been used to measure the three-dimensional distribution of X-ray of laser-plasma experiments in Xingguang II device, and the good results are obtained. This shows that a CT technique can be applied to ICF experiments.

Metric dimensional reduction at singularities with implications to Quantum Gravity

International Nuclear Information System (INIS)

Stoica, Ovidiu Cristinel

2014-01-01

A series of old and recent theoretical observations suggests that the quantization of gravity would be feasible, and some problems of Quantum Field Theory would go away if, somehow, the spacetime would undergo a dimensional reduction at high energy scales. But an identification of the deep mechanism causing this dimensional reduction would still be desirable. The main contribution of this article is to show that dimensional reduction effects are due to General Relativity at singularities, and do not need to be postulated ad-hoc. Recent advances in understanding the geometry of singularities do not require modification of General Relativity, being just non-singular extensions of its mathematics to the limit cases. They turn out to work fine for some known types of cosmological singularities (black holes and FLRW Big-Bang), allowing a choice of the fundamental geometric invariants and physical quantities which remain regular. The resulting equations are equivalent to the standard ones outside the singularities. One consequence of this mathematical approach to the singularities in General Relativity is a special, (geo)metric type of dimensional reduction: at singularities, the metric tensor becomes degenerate in certain spacetime directions, and some properties of the fields become independent of those directions. Effectively, it is like one or more dimensions of spacetime just vanish at singularities. This suggests that it is worth exploring the possibility that the geometry of singularities leads naturally to the spontaneous dimensional reduction needed by Quantum Gravity. - Highlights: • The singularities we introduce are described by finite geometric/physical objects. • Our singularities are accompanied by dimensional reduction effects. • They affect the metric, the measure, the topology, the gravitational DOF (Weyl = 0). • Effects proposed in other approaches to Quantum Gravity are obtained naturally. • The geometric dimensional reduction obtained

Experimental two-dimensional quantum walk on a photonic chip.

Science.gov (United States)

Tang, Hao; Lin, Xiao-Feng; Feng, Zhen; Chen, Jing-Yuan; Gao, Jun; Sun, Ke; Wang, Chao-Yue; Lai, Peng-Cheng; Xu, Xiao-Yun; Wang, Yao; Qiao, Lu-Feng; Yang, Ai-Lin; Jin, Xian-Min

2018-05-01

Quantum walks, in virtue of the coherent superposition and quantum interference, have exponential superiority over their classical counterpart in applications of quantum searching and quantum simulation. The quantum-enhanced power is highly related to the state space of quantum walks, which can be expanded by enlarging the photon number and/or the dimensions of the evolution network, but the former is considerably challenging due to probabilistic generation of single photons and multiplicative loss. We demonstrate a two-dimensional continuous-time quantum walk by using the external geometry of photonic waveguide arrays, rather than the inner degree of freedoms of photons. Using femtosecond laser direct writing, we construct a large-scale three-dimensional structure that forms a two-dimensional lattice with up to 49 × 49 nodes on a photonic chip. We demonstrate spatial two-dimensional quantum walks using heralded single photons and single photon-level imaging. We analyze the quantum transport properties via observing the ballistic evolution pattern and the variance profile, which agree well with simulation results. We further reveal the transient nature that is the unique feature for quantum walks of beyond one dimension. An architecture that allows a quantum walk to freely evolve in all directions and at a large scale, combining with defect and disorder control, may bring up powerful and versatile quantum walk machines for classically intractable problems.

A two-dimensional lattice equation as an extension of the Heideman-Hogan recurrence

Science.gov (United States)

Kamiya, Ryo; Kanki, Masataka; Mase, Takafumi; Tokihiro, Tetsuji

2018-03-01

We consider a two dimensional extension of the so-called linearizable mappings. In particular, we start from the Heideman-Hogan recurrence, which is known as one of the linearizable Somos-like recurrences, and introduce one of its two dimensional extensions. The two dimensional lattice equation we present is linearizable in both directions, and has the Laurent and the coprimeness properties. Moreover, its reduction produces a generalized family of the Heideman-Hogan recurrence. Higher order examples of two dimensional linearizable lattice equations related to the Dana Scott recurrence are also discussed.

Comparison of one-dimensional probabilistic finite element method with direct numerical simulation of dynamically loaded heterogeneous materials

Science.gov (United States)

Robbins, Joshua; Voth, Thomas

2011-06-01

Material response to dynamic loading is often dominated by microstructure such as grain topology, porosity, inclusions, and defects; however, many models rely on assumptions of homogeneity. We use the probabilistic finite element method (WK Liu, IJNME, 1986) to introduce local uncertainty to account for material heterogeneity. The PFEM uses statistical information about the local material response (i.e., its expectation, coefficient of variation, and autocorrelation) drawn from knowledge of the microstructure, single crystal behavior, and direct numerical simulation (DNS) to determine the expectation and covariance of the system response (velocity, strain, stress, etc). This approach is compared to resolved grain-scale simulations of the equivalent system. The microstructures used for the DNS are produced using Monte Carlo simulations of grain growth, and a sufficient number of realizations are computed to ensure a meaningful comparison. Finally, comments are made regarding the suitability of one-dimensional PFEM for modeling material heterogeneity. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Two-dimensional analytic weighting functions for limb scattering

Science.gov (United States)

Zawada, D. J.; Bourassa, A. E.; Degenstein, D. A.

2017-10-01

Through the inversion of limb scatter measurements it is possible to obtain vertical profiles of trace species in the atmosphere. Many of these inversion methods require what is often referred to as weighting functions, or derivatives of the radiance with respect to concentrations of trace species in the atmosphere. Several radiative transfer models have implemented analytic methods to calculate weighting functions, alleviating the computational burden of traditional numerical perturbation methods. Here we describe the implementation of analytic two-dimensional weighting functions, where derivatives are calculated relative to atmospheric constituents in a two-dimensional grid of altitude and angle along the line of sight direction, in the SASKTRAN-HR radiative transfer model. Two-dimensional weighting functions are required for two-dimensional inversions of limb scatter measurements. Examples are presented where the analytic two-dimensional weighting functions are calculated with an underlying one-dimensional atmosphere. It is shown that the analytic weighting functions are more accurate than ones calculated with a single scatter approximation, and are orders of magnitude faster than a typical perturbation method. Evidence is presented that weighting functions for stratospheric aerosols calculated under a single scatter approximation may not be suitable for use in retrieval algorithms under solar backscatter conditions.

A Three-Dimensional Microdisplacement Sensing System Based on MEMS Bulk-Silicon Technology

Science.gov (United States)

Wu, Junjie; Lei, Lihua; Chen, Xin; Cai, Xiaoyu; Li, Yuan; Han, Tao

2014-01-01

For the dimensional measurement and characterization of microsized and nanosized components, a three-dimensional microdisplacement sensing system was developed using the piezoresistive effect in silicon. The sensor was fabricated using microelectromechanical system bulk-silicon technology, and it was validated using the finite element method. A precise data acquisition circuit with an accuracy of 20 μV was designed to obtain weak voltage signals. By calibration, the sensing system was shown to have a sensitivity of 17.29 mV/μm and 4.59 mV/μm in the axial and lateral directions, respectively; the nonlinearity in these directions was 0.8% and 1.0% full scale, respectively. A full range of 4.6 μm was achieved in the axial direction. Results of a resolution test indicated that the sensing system had a resolution of 5 nm in the axial direction and 10 nm in the lateral direction. PMID:25360581

A Three-Dimensional Microdisplacement Sensing System Based on MEMS Bulk-Silicon Technology

Directory of Open Access Journals (Sweden)

Junjie Wu

2014-10-01

Full Text Available For the dimensional measurement and characterization of microsized and nanosized components, a three-dimensional microdisplacement sensing system was developed using the piezoresistive effect in silicon. The sensor was fabricated using microelectromechanical system bulk-silicon technology, and it was validated using the finite element method. A precise data acquisition circuit with an accuracy of 20 μV was designed to obtain weak voltage signals. By calibration, the sensing system was shown to have a sensitivity of 17.29 mV/μm and 4.59 mV/μm in the axial and lateral directions, respectively; the nonlinearity in these directions was 0.8% and 1.0% full scale, respectively. A full range of 4.6 μm was achieved in the axial direction. Results of a resolution test indicated that the sensing system had a resolution of 5 nm in the axial direction and 10 nm in the lateral direction.

Three-dimensional stability of solitary kinetic Alfven waves and ion-acoustic waves

International Nuclear Information System (INIS)

Ghosh, G.; Das, K.P.

1994-01-01

Starting from a set of equations that lead to a linear dispersion relation coupling kinetic Alfven waves and ion-acoustic waves, three-dimensional KdV equations are derived for these waves. These equations are then used to investigate the three-dimensional stability of solitary kinetic Alfven waves and ion-acoustic waves by the small-k perturbation expansion method of Rowlands and Infeld. For kinetic Alfven waves it is found that there is instability if the direction of the plane-wave perturbation lies inside a cone, and the growth rate of the instability attains a maximum when the direction of the perturbation lies in the plane containing the external magnetic field and the direction of propagation of the solitary wave. For ion-acoustic waves the growth rate of instability attains a maximum when the direction of the perturbation lies in a plane perpendicular to the direction of propagation of the solitary wave. (Author)

Analytical Prediction of Three Dimensional Chatter Stability in Milling

Science.gov (United States)

Altintas, Yusuf

The chip regeneration mechanism during chatter is influenced by vibrations in three directions when milling cutters with ball end, bull nose, or inclined cutting edges are used. A three dimensional chatter stability is modeled analytically in this article. The dynamic milling system is formulated as a function of cutter geometry, the frequency response of the machine tool structure at the cutting zone in three Cartesian directions, cutter engagement conditions and material property. The dynamic milling system with nonlinearities and periodic delayed differential equations is reduced to a three dimensional linear stability problem by approximations based on the physics of milling. The chatter stability lobes are predicted in the frequency domain using the proposed analytical solution, and verified experimentally in milling a Titanium alloy with a face milling cutter having circular inserts.

Generation of structurally novel short carotenoids and study of their biological activity

DEFF Research Database (Denmark)

Kim, Se Hyeuk; Kim, Moon S.; Lee, Bun Y.

2016-01-01

Recent research interest in phytochemicals has consistently driven the efforts in the metabolic engineering field toward microbial production of various carotenoids. In spite of systematic studies, the possibility of using C30 carotenoids as biologically functional compounds has not been explored...... thus far. Here, we generated 13 novel structures of C30 carotenoids and one C35 carotenoid, including acyclic, monocyclic, and bicyclic structures, through directed evolution and combinatorial biosynthesis, in Escherichia coli. Measurement of radical scavenging activity of various C30 carotenoid...... structures revealed that acyclic C30 carotenoids showed higher radical scavenging activity than did DL-atocopherol. We could assume high potential biological activity of the novel structures of C30 carotenoids as well, based on the neuronal differentiation activity observed for the monocyclic C30 carotenoid...

Three-dimensional ultrasound strain imaging of skeletal muscles

NARCIS (Netherlands)

Gijsbertse, K.; Sprengers, A. M. J.; Nillesen, M. M.; Hansen, Hendrik H.G.; Lopata, R.G.P.; Verdonschot, N.; de Korte, C. L.

2017-01-01

In this study, a multi-dimensional strain estimation method is presented to assess local relative deformation in three orthogonal directions in 3D space of skeletal muscles during voluntary contractions. A rigid translation and compressive deformation of a block phantom, that mimics muscle

Supersymmetric quantum mechanics in three-dimensional space, 1

International Nuclear Information System (INIS)

Ui, Haruo

1984-01-01

As a direct generalization of the model of supersymmetric quantum mechanics by Witten, which describes the motion of a spin one-half particle in the one-dimensional space, we construct a model of the supersymmetric quantum mechanics in the three-dimensional space, which describes the motion of a spin one-half particle in central and spin-orbit potentials in the context of the nonrelativistic quantum mechanics. With the simplest choice of the (super) potential, this model is shown to reduce to the model of the harmonic oscillator plus constant spin-orbit potential of unit strength of both positive and negative signs, which was studied in detail in our recent paper in connection with ''accidental degeneracy'' as well as the ''graded groups''. This simplest model is discussed in some detail as an example of the three-dimensional supersymmetric quantum mechanical system, where the supersymmetry is an exact symmetry of the system. More general choice of a polynomial superpotential is also discussed. It is shown that the supersymmetry cannot be spontaneously broken for any polynomial superpotential in our three-dimensional model; this result is contrasted to the corresponding one in the one-dimensional model. (author)

Nucleophile-directed selectivity towards linear carbonates in the niobium pentaethoxide-catalysed cycloaddition of CO2 and propylene oxide

KAUST Repository

Dutta, Barnali

2014-01-01

Homoleptic Nb-complexes combined with selected organic nucleophiles generate very active catalytic systems for the cycloaddition of propylene oxide and CO2 under ambient conditions. An unprecedented reaction pathway towards an acyclic organic carbonate is observed when extending the study to [Nb(OEt)5] in combination with 4-dimethylamino-pyridine (DMAP) or tetra-n-butylammonium bromide (TBAB). Mechanistic insights of the reaction are provided based on experimental and spectroscopic evidences. This journal is © the Partner Organisations 2014.

Electrochemically Functionalized Seamless Three-Dimensional Graphene-Carbon Nanotube Hybrid for Direct Electron Transfer of Glucose Oxidase and Bioelectrocatalysis.

Science.gov (United States)

Terse-Thakoor, Trupti; Komori, Kikuo; Ramnani, Pankaj; Lee, Ilkeun; Mulchandani, Ashok

2015-12-01

Three-dimensional seamless chemical vapor deposition (CVD) grown graphene-carbon nanotubes (G-CNT) hybrid film has been studied for its potential in achieving direct electron transfer (DET) of glucose oxidase (GOx) and its bioelectrocatalytic activity in glucose detection. A two-step CVD method was employed for the synthesis of seamless G-CNT hybrid film where CNTs are grown on already grown graphene film on copper foil using iron as a catalyst. Physical characterization using SEM and TEM show uniform dense coverage of multiwall carbon nanotubes (MWCNT) grown directly on graphene with seamless contacts. The G-CNT hybrid film was electrochemically modified to introduce oxygenated functional groups for DET favorable immobilization of GOx. Pristine and electrochemically functionalized G-CNT film was characterized by electrochemical impedance spectroscopy (EIS), cyclic voltammetry, X-ray photoelectron-spectroscopy, and Raman spectroscopy. The DET between GOx and electrochemically oxidized G-CNT electrode was studied using cyclic voltammetry which showed a pair of well-defined and quasi-reversible redox peaks with a formal potential of -459 mV at pH 7 corresponding to the redox site of GOx. The constructed electrode detected glucose concentration over the clinically relevant range of 2-8 mM with the highest sensitivity of 19.31 μA/mM/cm(2) compared to reported composite hybrid electrodes of graphene oxide and CNTs. Electrochemically functionalized CVD grown seamless G-CNT structure used in this work has potential to be used for development of artificial mediatorless redox enzyme based biosensors and biofuel cells.

A computational model for three-dimensional jointed media with a single joint set

International Nuclear Information System (INIS)

Koteras, J.R.

1994-02-01

This report describes a three-dimensional model for jointed rock or other media with a single set of joints. The joint set consists of evenly spaced joint planes. The normal joint response is nonlinear elastic and is based on a rational polynomial. Joint shear stress is treated as being linear elastic in the shear stress versus slip displacement before attaining a critical stress level governed by a Mohr-Coulomb faction criterion. The three-dimensional model represents an extension of a two-dimensional, multi-joint model that has been in use for several years. Although most of the concepts in the two-dimensional model translate in a straightforward manner to three dimensions, the concept of slip on the joint planes becomes more complex in three dimensions. While slip in two dimensions can be treated as a scalar quantity, it must be treated as a vector in the joint plane in three dimensions. For the three-dimensional model proposed here, the slip direction is assumed to be the direction of maximum principal strain in the joint plane. Five test problems are presented to verify the correctness of the computational implementation of the model

Unlabored system motion by specially conditioned electromagnetic fields in higher dimensional realms

Science.gov (United States)

David Froning, H.; Meholic, Gregory V.

2010-01-01

This third of three papers explores the possibility of swift, stress-less system transitions between slower-than-light and faster-than-light speeds with negligible net expenditure of system energetics. The previous papers derived a realm of higher dimensionality than 4-D spacetime that enabled such unlabored motion; and showed that fields that could propel and guide systems on unlabored paths in the higher dimensional realm must be fields that have been conditioned to SU(2) (or higher) Lie group symmetry. This paper shows that the system's surrounding vacuum dielectric ɛμ, within the higher dimensional realm's is a vector (not scalar) quantity with fixed magnitude ɛ0μ0 and changing direction within the realm with changing system speed. Thus, ɛμ generated by the system's EM field must remain tuned to vacuum ɛ0μ0 in both magnitude and direction during swift, unlabored system transitions between slower and faster than light speeds. As a result, the system's changing path and speed is such that the magnitude of the higher dimensional realm's ɛ0μ0 is not disturbed. And it is shown that a system's flight trajectories associated with its swift, unlabored transitions between zero and infinite speed can be represented by curved paths traced-out within the higher dimensional realm.

Higher dimensional discrete Cheeger inequalities

Directory of Open Access Journals (Sweden)

Anna Gundert

2015-01-01

Full Text Available For graphs there exists a strong connection between spectral and combinatorial expansion properties. This is expressed, e.g., by the discrete Cheeger inequality, the lower bound of which states that $\\lambda(G \\leq h(G$, where $\\lambda(G$ is the second smallest eigenvalue of the Laplacian of a graph $G$ and $h(G$ is the Cheeger constant measuring the edge expansion of $G$. We are interested in generalizations of expansion properties to finite simplicial complexes of higher dimension (or uniform hypergraphs. Whereas higher dimensional Laplacians were introduced already in 1945 by Eckmann, the generalization of edge expansion to simplicial complexes is not straightforward. Recently, a topologically motivated notion analogous to edge expansion that is based on $\\mathbb{Z}_2$-cohomology was introduced by Gromov and independently by Linial, Meshulam and Wallach. It is known that for this generalization there is no direct higher dimensional analogue of the lower bound of the Cheeger inequality. A different, combinatorially motivated generalization of the Cheeger constant, denoted by $h(X$, was studied by Parzanchevski, Rosenthal and Tessler. They showed that indeed $\\lambda(X \\leq h(X$, where $\\lambda(X$ is the smallest non-trivial eigenvalue of the ($(k-1$-dimensional upper Laplacian, for the case of $k$-dimensional simplicial complexes $X$ with complete $(k-1$-skeleton. Whether this inequality also holds for $k$-dimensional complexes with non-com\\-plete$(k-1$-skeleton has been an open question.We give two proofs of the inequality for arbitrary complexes. The proofs differ strongly in the methods and structures employed,and each allows for a different kind of additional strengthening of the original result.

Toward two-dimensional search engines

International Nuclear Information System (INIS)

Ermann, L; Shepelyansky, D L; Chepelianskii, A D

2012-01-01

We study the statistical properties of various directed networks using ranking of their nodes based on the dominant vectors of the Google matrix known as PageRank and CheiRank. On average PageRank orders nodes proportionally to a number of ingoing links, while CheiRank orders nodes proportionally to a number of outgoing links. In this way, the ranking of nodes becomes two dimensional which paves the way for the development of two-dimensional search engines of a new type. Statistical properties of information flow on the PageRank–CheiRank plane are analyzed for networks of British, French and Italian universities, Wikipedia, Linux Kernel, gene regulation and other networks. A special emphasis is done for British universities networks using the large database publicly available in the UK. Methods of spam links control are also analyzed. (paper)

Direct observation of two dimensional trace gas distributions with an airborne Imaging DOAS instrument

Directory of Open Access Journals (Sweden)

K.-P. Heue

2008-11-01

Full Text Available In many investigations of tropospheric chemistry information about the two dimensional distribution of trace gases on a small scale (e.g. tens to hundreds of metres is highly desirable. An airborne instrument based on imaging Differential Optical Absorption Spectroscopy has been built to map the two dimensional distribution of a series of relevant trace gases including NO₂, HCHO, C₂H₂O₂, H₂O, O₄, SO₂, and BrO on a scale of 100 m.

Here we report on the first tests of the novel aircraft instrument over the industrialised South African Highveld, where large variations in NO₂ column densities in the immediate vicinity of several sources e.g. power plants or steel works, were measured. The observed patterns in the trace gas distribution are interpreted with respect to flux estimates, and it is seen that the fine resolution of the measurements allows separate sources in close proximity to one another to be distinguished.

Approximate solutions for the two-dimensional integral transport equation. Solution of complex two-dimensional transport problems

International Nuclear Information System (INIS)

Sanchez, Richard.

1980-11-01

This work is divided into two parts: the first part deals with the solution of complex two-dimensional transport problems, the second one (note CEA-N-2166) treats the critically mixed methods of resolution. A set of approximate solutions for the isotropic two-dimensional neutron transport problem has been developed using the interface current formalism. The method has been applied to regular lattices of rectangular cells containing a fuel pin, cladding, and water, or homogenized structural material. The cells are divided into zones that are homogeneous. A zone-wise flux expansion is used to formulate a direct collision probability problem within a cell. The coupling of the cells is effected by making extra assumptions on the currents entering and leaving the interfaces. Two codes have been written: CALLIOPE uses a cylindrical cell model and one or three terms for the flux expansion, and NAUSICAA uses a two-dimensional flux representation and does a truly two-dimensional calculation inside each cell. In both codes, one or three terms can be used to make a space-independent expansion of the angular fluxes entering and leaving each side of the cell. The accuracies and computing times achieved with the different approximations are illustrated by numerical studies on two benchmark problems and by calculations performed in the APOLLO multigroup code [fr

Influence of dominance status on adrenal activity and ovarian cyclicity status in captive African elephants.

Science.gov (United States)

Proctor, Christine M; Freeman, Elizabeth W; Brown, Janine L

2010-01-01

The North American African (Loxodonta africana) elephant population is not self-sustaining, in part because of a high rate of abnormal ovarian activity. About 12% of adult females exhibit irregular cycles and 31% do not cycle at all. Our earlier work revealed a relationship between dominance status and ovarian acyclicity, with dominant females being more likely to not cycle normally. One theory is that dominant females may be expending more energy to maintaining peace within the captive herd than for supporting reproduction. The goal of this study was to determine if there was a relationship among dominance status, serum cortisol concentrations, and ovarian acyclicity. We hypothesized that adrenal glucocorticoid activity would be increased in dominant, noncycling elephants as compared with subdominant individuals. Blood samples were collected weekly over a 2-year period in 81 females of known dominance and cyclicity status, and analyzed for cortisol. Based on a path analysis model (Reticular Action Model Or Near Approximation [RAMONA]), noncycling, dominant African elephant females did not have higher mean serum cortisol concentrations, or exhibit more variability (i.e., coefficient of variation, standard deviation) in cortisol secretion. This study suggests that alterations in adrenal activity are not related to dominance status nor contribute directly to acyclicity in captive African elephants.

Quantitative Three-Dimensional Characterization of Block Copolymer Directed Self-Assembly on Combined Chemical and Topographical Prepatterned Templates.

Science.gov (United States)

Segal-Peretz, Tamar; Ren, Jiaxing; Xiong, Shisheng; Khaira, Gurdaman; Bowen, Alec; Ocola, Leonidas E; Divan, Ralu; Doxastakis, Manolis; Ferrier, Nicola J; de Pablo, Juan; Nealey, Paul F

2017-02-28

Characterization of the three-dimensional (3D) structure in directed self-assembly (DSA) of block copolymers is crucial for understanding the complex relationships between the guiding template and the resulting polymer structure so DSA could be successfully implemented for advanced lithography applications. Here, we combined scanning transmission electron microscopy (STEM) tomography and coarse-grain simulations to probe the 3D structure of P2VP-b-PS-b-P2VP assembled on prepatterned templates using solvent vapor annealing. The templates consisted of nonpreferential background and raised guiding stripes that had PS-preferential top surfaces and P2VP-preferential sidewalls. The full 3D characterization allowed us to quantify the shape of the polymer domains and the interface between domains as a function of depth in the film and template geometry and offered important insights that were not accessible with 2D metrology. Sidewall guiding was advantageous in promoting the alignment and lowering the roughness of the P2VP domains over the sidewalls, but incommensurate confinement from the increased topography could cause roughness and intermittent dislocations in domains over the background region at the bottom of the film. The 3D characterization of bridge structures between domains over the background and breaks within domains on guiding lines sheds light on possible origins of common DSA defects. The positional fluctuations of the PS/P2VP interface between domains showed a depth-dependent behavior, with high levels of fluctuations near both the free surface of the film and the substrate and lower fluctuation levels in the middle of the film. This research demonstrates how 3D characterization offers a better understanding of DSA processes, leading to better design and fabrication of directing templates.

Purification of 3H-dihydroalprenolol by two dimensional thin layer chromatography

International Nuclear Information System (INIS)

Smisterova, J.; Soltes, L.; Kallay, Z.

1989-01-01

A two dimensional thin-layer chromatographic method was developed for the purification and analysis of (-)-[ 3 H]dihydroalprenolol by using an acidic mobile phase (butanol/water/acetic acid 25:10:4, v/v) in one direction and a basic eluent (chloroform/acetone/triethylamine 50:40:10, v/v) in another direction. (author)

Three dimensional imaging of surface geometry in SEM

International Nuclear Information System (INIS)

Slowko, W.

1997-01-01

A great advantage of scanning electron microscopy (SEM) is its ability of the surface topography in the way as a human eye is accustomed to see lights and shadows on macroobjects. However, SEM's can hardly display vertical dimensions of the structures. One of possible solutions is reconstruction of the surface profiles by directional detection of secondary electrons and proper signal processing. However, the surface profile still gives two dimensional information and the method should be extended to obtain fully three dimensional imaging. The extension consists in a simultaneous reconstruction of the surface profiles in two perpendicular directions (x and y) and their superposition. The solution proposed is based on a quadrupole detector system and a computer or analogue system for signal processing. Quantitative data of the surface topography can be displayed in many manners in the system of two or three co-ordinates with use of pseudo-colour for the altitude coding. (author)

Logarithmic Superdiffusion in Two Dimensional Driven Lattice Gases

Science.gov (United States)

Krug, J.; Neiss, R. A.; Schadschneider, A.; Schmidt, J.

2018-03-01

The spreading of density fluctuations in two-dimensional driven diffusive systems is marginally anomalous. Mode coupling theory predicts that the diffusivity in the direction of the drive diverges with time as (ln t)^{2/3} with a prefactor depending on the macroscopic current-density relation and the diffusion tensor of the fluctuating hydrodynamic field equation. Here we present the first numerical verification of this behavior for a particular version of the two-dimensional asymmetric exclusion process. Particles jump strictly asymmetrically along one of the lattice directions and symmetrically along the other, and an anisotropy parameter p governs the ratio between the two rates. Using a novel massively parallel coupling algorithm that strongly reduces the fluctuations in the numerical estimate of the two-point correlation function, we are able to accurately determine the exponent of the logarithmic correction. In addition, the variation of the prefactor with p provides a stringent test of mode coupling theory.

A three-dimensional neutron transport benchmark solution

International Nuclear Information System (INIS)

Ganapol, B.D.; Kornreich, D.E.

1993-01-01

For one-group neutron transport theory in one dimension, several powerful analytical techniques have been developed to solve the neutron transport equation, including Caseology, Wiener-Hopf factorization, and Fourier and Laplace transform methods. In addition, after a Fourier transform in the transverse plane and formulation of a pseudo problem, two-dimensional (2-D) and three-dimensional (3-D) problems can be solved using the techniques specifically developed for the one-dimensional (1-D) case. Numerical evaluation of the resulting expressions requiring an inversion in the transverse plane have been successful for 2-D problems but becomes exceedingly difficult in the 3-D case. In this paper, we show that by using the symmetry along the beam direction, a 2-D problem can be transformed into a 3-D problem in an infinite medium. The numerical solution to the 3-D problem is then demonstrated. Thus, a true 3-D transport benchmark solution can be obtained from a well-established numerical solution to a 2-D problem

Magnetic field effect on a three-dimensional mixed convective flow ...

African Journals Online (AJOL)

A uniform magnetic field is assumed to be applied transversely to the direction of the free stream. The expressions for skin friction at the plate in the direction of the main flow and the rate of heat transfer and mass transfer from the plate to the fluid are obtained in non-dimensional form. The amplitudes of the perturbed parts of ...

One-dimensional low spatial frequency LIPSS with rotating orientation on fused silica

Energy Technology Data Exchange (ETDEWEB)

Schwarz, Simon, E-mail: simon.schwarz@h-ab.de; Rung, Stefan; Hellmann, Ralf

2017-07-31

Highlights: • Generation of one-dimensional low spatial frequency LIPSS on transparent material. • Varying the angle of incidence results in a rotation of the one-dimensional LSFL. • Rotation angle of LSFL decreases with increasing the applied fluence. • Orientation of the LSFL is mirror-inverted when reversing the scanning direction. - Abstract: We report on the generation of one-dimensional low spatial frequency LIPSS on transparent material. The influence of the applied laser fluence and angle of incidence on the periodicity, orientation and quality of the one-dimensional low spatial frequency LIPSS is investigated, facilitating the generation of highly uniform LIPSS alongside a line. Most strikingly, however, we observe a previously unreported effect of a pronounced rotation of the one-dimensional low spatial frequency LIPSS for varying angle of incidence upon inclined laser irradiation.

Three-dimensional features on oscillating microbubbles streaming flows

Science.gov (United States)

Rossi, Massimiliano; Marin, Alvaro G.; Wang, Cheng; Hilgenfeldt, Sascha; Kähler, Christian J.

2013-11-01

Ultrasound-driven oscillating micro-bubbles have been used as active actuators in microfluidic devices to perform manifold tasks such as mixing, sorting and manipulation of microparticles. A common configuration consists in side-bubbles, created by trapping air pockets in blind channels perpendicular to the main channel direction. This configuration results in bubbles with a semi-cylindrical shape that creates a streaming flow generally considered quasi two-dimensional. However, recent experiments performed with three-dimensional velocimetry methods have shown how microparticles can present significant three-dimensional trajectories, especially in regions close to the bubble interface. Several reasons will be discussed such as boundary effects of the bottom/top wall, deformation of the bubble interface leading to more complex vibrational modes, or bubble-particle interactions. In the present investigation, precise measurements of particle trajectories close to the bubble interface will be performed by means of 3D Astigmatic Particle Tracking Velocimetry. The results will allow us to characterize quantitatively the three-dimensional features of the streaming flow and to estimate its implications in practical applications as particle trapping, sorting or mixing.

Future device applications of low-dimensional carbon superlattice structures

Science.gov (United States)

Bhattacharyya, Somnath

2005-03-01

We observe superior transport properties in low-dimensional amorphous carbon (a-C) and superlattice structures fabricated by a number of different techniques. Low temperature conductivity of these materials is explained using argument based on the crossover of dimensionality of weak localization and electron-electron interactions along with a change of sign of the magneto-resistance. These trends are significantly different from many other well characterized ordered or oriented carbon structures, and, show direct evidence of high correlation length, mobility and an effect of the dimensionality in low-dimensional a-C films. We show routes to prepare bespoke features by tuning the phase relaxation time in order to make high-speed devices over large areas. The artificially grown multi-layer superlattice structures of diamond-like amorphous carbon films show high-frequency resonance and quantum conductance suggesting sufficiently high values of phase coherence length in the present disordered a-C system that could lead to fast switching multi-valued logic.

DFT investigation on two-dimensional GeS/WS2 van der Waals heterostructure for direct Z-scheme photocatalytic overall water splitting

Science.gov (United States)

Ju, Lin; Dai, Ying; Wei, Wei; Li, Mengmeng; Huang, Baibiao

2018-03-01

Recently, extensive attention has been paid to the direct Z-scheme systems for photocatalytic water splitting where carriers migrate directly between the two semiconductors without a redox mediator. In the present work, the electronic structure and related properties of two-dimensional (2D) van de Waals (vdW) GeS/WX2 (X = O, S, Se, Te) heterojunction are systematically investigated by first-principles calculations. Our results demonstrate that, the GeS/WS2 heterojunction could form a direct Z-scheme system for photocatalytic water splitting, whereas the GeS/WX2 (X = O, Se, Te) can't, because of their respective unsuitable electronic structures. For the GeS/WS2 heterojunction, the GeS and WS2 monolayers serve as photocatalysts for the hydrogen evolution reactionand oxygen evolution reaction, respectively. The internal electric field induced by the electron transfer at the interface can promote the separation of photo-generated charge carriers and formation of the interface Z-scheme electron transfer. Remarkably, the designed GeS/WS2 heterojunction not only enhances the hydrogen production activity of GeS and the oxygen production ability of WS2 but also improves the light absorption of the two monolayers by reducing the band gaps. Moreover, it is found that narrowing the interlayer distance could enhance the internal electric field, improving the photocatalytic ability of the vdW heterojunction. This work provides fundamental insights for further design and preparation of emergent metal dichalcogenide catalysts, beneficial for the development in clean energy.

Method and apparatus for the electro-optic convolution of a one-dimensional signal

International Nuclear Information System (INIS)

1979-01-01

Procedure for the electro-optic convolution of a signal and a filter function, whereby the one dimensional electro-optical signal would be portrayed as a line along which the clarity varies and whereby filter function is determined by one or more masks, whilst after each mask is placed a light detector, with which the light passing through the masks may be detected, whilst a one-dimensional portrayal of the signal along the masks will be developed, characterised in that a one dimensional portrayal of the signal, with the aid of an optical system in a direction across the line, will be enlarged, and that this enlarged signal in the direction of the line along the masks will be affected which the masks closing fields will contain, which are either fully transparent or are fully non-transparent. (Auth.)

The applications of a higher-dimensional Lie algebra and its decomposed subalgebras.

Science.gov (United States)

Yu, Zhang; Zhang, Yufeng

2009-01-15

With the help of invertible linear transformations and the known Lie algebras, a higher-dimensional 6 x 6 matrix Lie algebra smu(6) is constructed. It follows a type of new loop algebra is presented. By using a (2 + 1)-dimensional partial-differential equation hierarchy we obtain the integrable coupling of the (2 + 1)-dimensional KN integrable hierarchy, then its corresponding Hamiltonian structure is worked out by employing the quadratic-form identity. Furthermore, a higher-dimensional Lie algebra denoted by E, is given by decomposing the Lie algebra smu(6), then a discrete lattice integrable coupling system is produced. A remarkable feature of the Lie algebras smu(6) and E is used to directly construct integrable couplings.

Medical image compression by using three-dimensional wavelet transformation

International Nuclear Information System (INIS)

Wang, J.; Huang, H.K.

1996-01-01

This paper proposes a three-dimensional (3-D) medical image compression method for computed tomography (CT) and magnetic resonance (MR) that uses a separable nonuniform 3-D wavelet transform. The separable wavelet transform employs one filter bank within two-dimensional (2-D) slices and then a second filter bank on the slice direction. CT and MR image sets normally have different resolutions within a slice and between slices. The pixel distances within a slice are normally less than 1 mm and the distance between slices can vary from 1 mm to 10 mm. To find the best filter bank in the slice direction, the authors use the various filter banks in the slice direction and compare the compression results. The results from the 12 selected MR and CT image sets at various slice thickness show that the Haar transform in the slice direction gives the optimum performance for most image sets, except for a CT image set which has 1 mm slice distance. Compared with 2-D wavelet compression, compression ratios of the 3-D method are about 70% higher for CT and 35% higher for MR image sets at a peak signal to noise ratio (PSNR) of 50 dB. In general, the smaller the slice distance, the better the 3-D compression performance

Quasi-one-dimensional scattering in a discrete model

DEFF Research Database (Denmark)

Valiente, Manuel; Mølmer, Klaus

2011-01-01

We study quasi-one-dimensional scattering of one and two particles with short-range interactions on a discrete lattice model in two dimensions. One of the directions is tightly confined by an arbitrary trapping potential. We obtain the collisional properties of these systems both at finite and zero...

One-Dimensional Photonic Crystal Superprisms

Science.gov (United States)

Ting, David

2005-01-01

Theoretical calculations indicate that it should be possible for one-dimensional (1D) photonic crystals (see figure) to exhibit giant dispersions known as the superprism effect. Previously, three-dimensional (3D) photonic crystal superprisms have demonstrated strong wavelength dispersion - about 500 times that of conventional prisms and diffraction gratings. Unlike diffraction gratings, superprisms do not exhibit zero-order transmission or higher-order diffraction, thereby eliminating cross-talk problems. However, the fabrication of these 3D photonic crystals requires complex electron-beam substrate patterning and multilayer thin-film sputtering processes. The proposed 1D superprism is much simpler in structural complexity and, therefore, easier to design and fabricate. Like their 3D counterparts, the 1D superprisms can exhibit giant dispersions over small spectral bands that can be tailored by judicious structure design and tuned by varying incident beam direction. Potential applications include miniature gas-sensing devices.

Cohesive motion in one-dimensional flocking

International Nuclear Information System (INIS)

Dossetti, V

2012-01-01

A one-dimensional rule-based model for flocking, which combines velocity alignment and long-range centering interactions, is presented and studied. The induced cohesion in the collective motion of the self-propelled agents leads to unique group behavior that contrasts with previous studies. Our results show that the largest cluster of particles, in the condensed states, develops a mean velocity slower than the preferred one in the absence of noise. For strong noise, the system also develops a non-vanishing mean velocity, alternating its direction of motion stochastically. This allows us to address the directional switching phenomenon. The effects of different sources of stochasticity on the system are also discussed. (paper)

On higher dimensional Einstein spacetimes with a non-degenerate double Weyl aligned null direction

Czech Academy of Sciences Publication Activity Database

Ortaggio, Marcello; Pravda, Vojtěch; Pravdová, Alena

Roč. 35, č. 7 ( 2018 ), č. článku 075004. ISSN 0264-9381 R&D Projects: GA ČR GB14-37086G Institutional support: RVO:67985840 Keywords : higher-dimensional gravity * WANDs * Weyl tensor Subject RIV: BA - General Mathematics OBOR OECD: Applied mathematics Impact factor: 3.119, year: 2016 http://iopscience.iop.org/article/10.1088/1361-6382/aaae25

Discretization model for nonlinear dynamic analysis of three dimensional structures

International Nuclear Information System (INIS)

Hayashi, Y.

1982-12-01

A discretization model for nonlinear dynamic analysis of three dimensional structures is presented. The discretization is achieved through a three dimensional spring-mass system and the dynamic response obtained by direct integration of the equations of motion using central diferences. First the viability of the model is verified through the analysis of homogeneous linear structures and then its performance in the analysis of structures subjected to impulsive or impact loads, taking into account both geometrical and physical nonlinearities is evaluated. (Author) [pt

A stock market forecasting model combining two-directional two-dimensional principal component analysis and radial basis function neural network.

Science.gov (United States)

Guo, Zhiqiang; Wang, Huaiqing; Yang, Jie; Miller, David J

2015-01-01

In this paper, we propose and implement a hybrid model combining two-directional two-dimensional principal component analysis ((2D)2PCA) and a Radial Basis Function Neural Network (RBFNN) to forecast stock market behavior. First, 36 stock market technical variables are selected as the input features, and a sliding window is used to obtain the input data of the model. Next, (2D)2PCA is utilized to reduce the dimension of the data and extract its intrinsic features. Finally, an RBFNN accepts the data processed by (2D)2PCA to forecast the next day's stock price or movement. The proposed model is used on the Shanghai stock market index, and the experiments show that the model achieves a good level of fitness. The proposed model is then compared with one that uses the traditional dimension reduction method principal component analysis (PCA) and independent component analysis (ICA). The empirical results show that the proposed model outperforms the PCA-based model, as well as alternative models based on ICA and on the multilayer perceptron.

Mechanical stretching for tissue engineering: two-dimensional and three-dimensional constructs.

Science.gov (United States)

Riehl, Brandon D; Park, Jae-Hong; Kwon, Il Keun; Lim, Jung Yul

2012-08-01

Mechanical cell stretching may be an attractive strategy for the tissue engineering of mechanically functional tissues. It has been demonstrated that cell growth and differentiation can be guided by cell stretch with minimal help from soluble factors and engineered tissues that are mechanically stretched in bioreactors may have superior organization, functionality, and strength compared with unstretched counterparts. This review explores recent studies on cell stretching in both two-dimensional (2D) and three-dimensional (3D) setups focusing on the applications of stretch stimulation as a tool for controlling cell orientation, growth, gene expression, lineage commitment, and differentiation and for achieving successful tissue engineering of mechanically functional tissues, including cardiac, muscle, vasculature, ligament, tendon, bone, and so on. Custom stretching devices and lab-specific mechanical bioreactors are described with a discussion on capabilities and limitations. While stretch mechanotransduction pathways have been examined using 2D stretch, studying such pathways in physiologically relevant 3D environments may be required to understand how cells direct tissue development under stretch. Cell stretch study using 3D milieus may also help to develop tissue-specific stretch regimens optimized with biochemical feedback, which once developed will provide optimal tissue engineering protocols.

Three-dimensional instability of standing waves

Science.gov (United States)

Zhu, Qiang; Liu, Yuming; Yue, Dick K. P.

2003-12-01

We investigate the three-dimensional instability of finite-amplitude standing surface waves under the influence of gravity. The analysis employs the transition matrix (TM) approach and uses a new high-order spectral element (HOSE) method for computation of the nonlinear wave dynamics. HOSE is an extension of the original high-order spectral method (HOS) wherein nonlinear wave wave and wave body interactions are retained up to high order in wave steepness. Instead of global basis functions in HOS, however, HOSE employs spectral elements to allow for complex free-surface geometries and surface-piercing bodies. Exponential convergence of HOS with respect to the total number of spectral modes (for a fixed number of elements) and interaction order is retained in HOSE. In this study, we use TM-HOSE to obtain the stability of general three-dimensional perturbations (on a two-dimensional surface) on two classes of standing waves: plane standing waves in a rectangular tank; and radial/azimuthal standing waves in a circular basin. For plane standing waves, we confirm the known result of two-dimensional side-bandlike instability. In addition, we find a novel three-dimensional instability for base flow of any amplitude. The dominant component of the unstable disturbance is an oblique (standing) wave oriented at an arbitrary angle whose frequency is close to the (nonlinear) frequency of the original standing wave. This finding is confirmed by direct long-time simulations using HOSE which show that the nonlinear evolution leads to classical Fermi Pasta Ulam recurrence. For the circular basin, we find that, beyond a threshold wave steepness, a standing wave (of nonlinear frequency Omega) is unstable to three-dimensional perturbations. The unstable perturbation contains two dominant (standing-wave) components, the sum of whose frequencies is close to 2Omega. From the cases we consider, the critical wave steepness is found to generally decrease/increase with increasing radial

Analytic study of solutions for a (3 + 1) -dimensional generalized KP equation

Science.gov (United States)

Gao, Hui; Cheng, Wenguang; Xu, Tianzhou; Wang, Gangwei

2018-03-01

The (3 + 1) -dimensional generalized KP (gKP) equation is an important nonlinear partial differential equation in theoretical and mathematical physics which can be used to describe nonlinear wave motion. Through the Hirota bilinear method, one-solition, two-solition and N-solition solutions are derived via symbolic computation. Two classes of lump solutions, rationally localized in all directions in space, to the dimensionally reduced cases in (2 + 1)-dimensions, are constructed by using a direct method based on the Hirota bilinear form of the equation. It implies that we can derive the lump solutions of the reduced gKP equation from positive quadratic function solutions to the aforementioned bilinear equation. Meanwhile, we get interaction solutions between a lump and a kink of the gKP equation. The lump appears from a kink and is swallowed by it with the change of time. This work offers a possibility which can enrich the variety of the dynamical features of solutions for higher-dimensional nonlinear evolution equations.

Three dimensional analysis of cosmic ray intensity variation

International Nuclear Information System (INIS)

Yasue, Shin-ichi; Mori, Satoru; Nagashima, Kazuo.

1974-01-01

Three dimensional analysis of cosmic ray anisotropy and its time variation was performed. This paper describes the analysis of the Forbush decrease in Jan. 1968 to investigate by comparing the direction of the magnetic field in interplanetary space and the direction of the reference axis for cosmic ray anisotropy. New anisotropy becomes dominant at the time of Forbush decrease because the anisotropy of cosmic ray in calm state is wiped out. Such anisotropy produces intensity variation in neutron monitors on the ground. The characteristic parameters of three dimensional anisotropy can be determined from theoretical value and observed intensity. Analyzed data were taken for 6 days from Jan. 25 to Jan. 30, 1968, at Deep River. The decrease of intensity at Deep River was seen for several hours from 11 o'clock (UT), Jan. 26, just before The Forbush decrease. This may be due to the loss cone. The Forbush decrease began at 19 o'clock, Jan. 26, and the main phase continued to 5 o'clock in the next morning. The spectrum of variation was Psup(-0.5). The time variations of the magnetic field in interplanetary space and the reference axis of cosmic ray anisotropy are shown for 15 hours. The average directions of both are almost in coincidence. The spatial distribution of cosmic ray near the earth may be expressed by the superposition of axial symmetrical distribution along a reference axis and its push-out to the direction of 12 o'clock. It is considered that the direction of magnetic force line and the velocity of solar wind correspond to the direction of the reference axis and the magnitude of anisotropy in the direction of 12 o'clock, respectively. (Kato, T.)

Turbulence in Three Dimensional Simulations of Magnetopause Reconnection

Science.gov (United States)

Drake, J. F.; Price, L.; Swisdak, M.; Burch, J. L.; Cassak, P.; Dahlin, J. T.; Ergun, R.

2017-12-01

We present two- and three-dimensional particle-in-cell simulations of the 16 October 2015 MMS magnetopause reconnection event. While the two-dimensional simulation is laminar, turbulence develops at both the x-line and along the magnetic separatrices in the three-dimensional simulation. This turbulence is electromagnetic in nature, is characterized by a wavevector k given by kρ e ˜(m_e/m_i)0.25 with ρ e the electron Larmor radius, and appears to have the ion pressure gradient as its source of free energy. Taken together, these results suggest the instability is a variant of the lower-hybrid drift instability. The turbulence produces electric field fluctuations in the out-of-plane direction (the direction of the reconnection electric field) with an amplitude of around ± 10 mV/m, which is much greater than the reconnection electric field of around 0.1 mV/m. Such large values of the out-of-plane electric field have been identified in the MMS data. The turbulence in the simulation controls the scale lengths of the density profile and current layers in asymmetric reconnection, driving them closer to √ {ρ eρ_i } than the ρ e or de scalings seen in 2D reconnection simulations, where de is the electron inertial length. The turbulence is strong enough to make the magnetic field around the reconnection island chaotic and produces both anomalous resistivity and anomalous viscosity. Each contribute significantly to breaking the frozen-in condition in the electron diffusion region. The crescent-shaped features in velocity space seen both in MMS observations and in two-dimensional simulations survive, even in the turbulent environment of the three-dimensional system. We compare and contrast these results to a three-dimensional simulation of the 8 December 2015 MMS magnetopause reconnection event in which the reconnecting and out-of-plane guide fields are comparable. LHDI is still present in this event, although its appearance is modified by the presence of the guide

Metrological AFMs and its application for versatile nano-dimensional metrology tasks

Science.gov (United States)

Dai, Gaoliang; Dziomba, T.; Pohlenz, F.; Danzebrink, H.-U.; Koenders, L.

2010-08-01

Traceable calibrations of various micro and nano measurement devices are crucial tasks for ensuring reliable measurements for micro and nanotechnology. Today metrological AFM are widely used for traceable calibrations of nano dimensional standards. In this paper, we introduced the developments of metrological force microscopes at PTB. Of the three metrological AFMs described here, one is capable of measuring in a volume of 25 mm x 25 mm x 5 mm. All instruments feature interferometers and the three-dimensional position measurements are thus directly traceable to the metre definition. Some calibration examples on, for instance, flatness standards, step height standards, one and two dimensional gratings are demonstrated.

Innovative three-dimensional neutronics analyses directly coupled with cad models of geometrically complex fusion systems

International Nuclear Information System (INIS)

Sawan, M.; Wilson, P.; El-Guebaly, L.; Henderson, D.; Sviatoslavsky, G.; Bohm, T.; Kiedrowski, B.; Ibrahim, A.; Smith, B.; Slaybaugh, R.; Tautges, T.

2007-01-01

Fusion systems are, in general, geometrically complex requiring detailed three-dimensional (3-D) nuclear analysis. This analysis is required to address tritium self-sufficiency, nuclear heating, radiation damage, shielding, and radiation streaming issues. To facilitate such calculations, we developed an innovative computational tool that is based on the continuous energy Monte Carlo code MCNP and permits the direct use of CAD-based solid models in the ray-tracing. This allows performing the neutronics calculations in a model that preserves the geometrical details without any simplification, eliminates possible human error in modeling the geometry for MCNP, and allows faster design iterations. In addition to improving the work flow for simulating complex 3- D geometries, it allows a richer representation of the geometry compared to the standard 2nd order polynomial representation. This newly developed tool has been successfully tested for a detailed 40 degree sector benchmark of the International Thermonuclear Experimental Reactor (ITER). The calculations included determining the poloidal variation of the neutron wall loading, flux and nuclear heating in the divertor components, nuclear heating in toroidal field coils, and radiation streaming in the mid-plane port. The tool has been applied to perform 3-D nuclear analysis for several fusion designs including the ARIES Compact Stellarator (ARIES-CS), the High Average Power Laser (HAPL) inertial fusion power plant, and ITER first wall/shield (FWS) modules. The ARIES-CS stellarator has a first wall shape and a plasma profile that varies toroidally within each field period compared to the uniform toroidal shape in tokamaks. Such variation cannot be modeled analytically in the standard MCNP code. The impact of the complex helical geometry and the non-uniform blanket and divertor on the overall tritium breeding ratio and total nuclear heating was determined. In addition, we calculated the neutron wall loading variation in

ONE-DIMENSIONAL AND TWO-DIMENSIONAL LEADERSHIP STYLES

Directory of Open Access Journals (Sweden)

Nikola Stefanović

2007-06-01

Full Text Available In order to motivate their group members to perform certain tasks, leaders use different leadership styles. These styles are based on leaders' backgrounds, knowledge, values, experiences, and expectations. The one-dimensional styles, used by many world leaders, are autocratic and democratic styles. These styles lie on the two opposite sides of the leadership spectrum. In order to precisely define the leadership styles on the spectrum between the autocratic leadership style and the democratic leadership style, leadership theory researchers use two dimensional matrices. The two-dimensional matrices define leadership styles on the basis of different parameters. By using these parameters, one can identify two-dimensional styles.

Self-deformation in a direct current driven helium jet micro discharge

International Nuclear Information System (INIS)

Xu, S. F.; Zhong, X. X.

2016-01-01

We report on the experimental observation of three dimensional self-deformation in an atmospheric micro discharge of the helium microjet through a tube into the ambient air upon a water electrode. The geometry of the discharge system is axial symmetric. While decreasing the discharge current, three dimensional collective motion of plasma filaments is directly observed. The three dimensional configuration of the discharge self changed from an axial symmetrical horn to a rectangular horn when the water acts as a cathode

Self-deformation in a direct current driven helium jet micro discharge

Energy Technology Data Exchange (ETDEWEB)

Xu, S. F.; Zhong, X. X., E-mail: xxzhong@sjtu.edu.cn [State Key Laboratory of Advanced Optical Communication Systems and Networks and Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China)

2016-01-15

We report on the experimental observation of three dimensional self-deformation in an atmospheric micro discharge of the helium microjet through a tube into the ambient air upon a water electrode. The geometry of the discharge system is axial symmetric. While decreasing the discharge current, three dimensional collective motion of plasma filaments is directly observed. The three dimensional configuration of the discharge self changed from an axial symmetrical horn to a rectangular horn when the water acts as a cathode.

Self-deformation in a direct current driven helium jet micro discharge

Science.gov (United States)

Xu, S. F.; Zhong, X. X.

2016-01-01

We report on the experimental observation of three dimensional self-deformation in an atmospheric micro discharge of the helium microjet through a tube into the ambient air upon a water electrode. The geometry of the discharge system is axial symmetric. While decreasing the discharge current, three dimensional collective motion of plasma filaments is directly observed. The three dimensional configuration of the discharge self changed from an axial symmetrical horn to a rectangular horn when the water acts as a cathode.

Directional reflectance factor distributions of a cotton row crop

Science.gov (United States)

Kimes, D. S.; Newcomb, W. W.; Schutt, J. B.; Pinter, P. J., Jr.; Jackson, R. D.

1984-01-01

The directional reflectance factor distribution spanning the entire exitance hemisphere was measured for a cotton row crop (Gossypium barbadense L.) with 39 percent ground cover. Spectral directional radiances were taken in NOAA satellite 7 AVHRR bands 1 and 2 using a three-band radiometer with restricted 12 deg full angle field of view at half peak power points. Polar co-ordinate system plots of directional reflectance factor distributions and three-dimensional computer graphic plots of scattered flux were used to study the dynamics of the directional reflectance factor distribution as a function of spectral band, geometric structure of the scene, solar zenith and azimuth angles, and optical properties of the leaves and soil. The factor distribution of the incomplete row crops was highly polymodal relative to that for complete vegetation canopies. Besides the enhanced reflectance for the antisolar point, a reflectance minimum was observed towards the forwardscatter direction in the principle plane of the sun. Knowledge of the mechanics of the observed dynamics of the data may be used to provide rigorous validation for two- or three-dimensional radiative transfer models, and is important in interpreting aircraft and satellite data where the solar angle varies widely.

The blind student’s interpretation of two-dimensional shapes in geometry

Science.gov (United States)

Andriyani; Budayasa, I. K.; Juniati, D.

2018-01-01

The blind student’s interpretation of two-dimensional shapes represents the blind student’s mental image of two-dimensional shapes that they can’t visualize directly, which is related to illustration of the characteristics and number of edges and angles. The objective of this research is to identify the blind student’s interpretation of two-dimensional shapes. This research was an exploratory study with qualitative approach. A subject of this research is a sixth-grade student who experiencing total blind from the fifth grade of elementary school. Researchers interviewed the subject about his interpretation of two-dimensional shapes according to his thinking.The findings of this study show the uniqueness of blind students, who have been totally blind since school age, in knowing and illustrating the characteristics of edges and angles of two-dimensional shapes by utilizing visual experiences that were previously obtained before the blind. The result can inspire teachers to design further learning for development of blind student geometry concepts.

Elastic wave localization in two-dimensional phononic crystals with one-dimensional random disorder and aperiodicity

International Nuclear Information System (INIS)

Yan Zhizhong; Zhang Chuanzeng; Wang Yuesheng

2011-01-01

The band structures of in-plane elastic waves propagating in two-dimensional phononic crystals with one-dimensional random disorder and aperiodicity are analyzed in this paper. The localization of wave propagation is discussed by introducing the concept of the localization factor, which is calculated by the plane-wave-based transfer-matrix method. By treating the random disorder and aperiodicity as the deviation from the periodicity in a special way, three kinds of aperiodic phononic crystals that have normally distributed random disorder, Thue-Morse and Rudin-Shapiro sequence in one direction and translational symmetry in the other direction are considered and the band structures are characterized using localization factors. Besides, as a special case, we analyze the band gap properties of a periodic planar layered composite containing a periodic array of square inclusions. The transmission coefficients based on eigen-mode matching theory are also calculated and the results show the same behaviors as the localization factor does. In the case of random disorders, the localization degree of the normally distributed random disorder is larger than that of the uniformly distributed random disorder although the eigenstates are both localized no matter what types of random disorders, whereas, for the case of Thue-Morse and Rudin-Shapiro structures, the band structures of Thue-Morse sequence exhibit similarities with the quasi-periodic (Fibonacci) sequence not present in the results of the Rudin-Shapiro sequence.

Two-Dimensional Extreme Learning Machine

Directory of Open Access Journals (Sweden)

Bo Jia

2015-01-01

(BP networks. However, like many other methods, ELM is originally proposed to handle vector pattern while nonvector patterns in real applications need to be explored, such as image data. We propose the two-dimensional extreme learning machine (2DELM based on the very natural idea to deal with matrix data directly. Unlike original ELM which handles vectors, 2DELM take the matrices as input features without vectorization. Empirical studies on several real image datasets show the efficiency and effectiveness of the algorithm.

Two-dimensional Semiconductor-Superconductor Hybrids

DEFF Research Database (Denmark)

Suominen, Henri Juhani

This thesis investigates hybrid two-dimensional semiconductor-superconductor (Sm-S) devices and presents a new material platform exhibiting intimate Sm-S coupling straight out of the box. Starting with the conventional approach, we investigate coupling superconductors to buried quantum well....... To overcome these issues we integrate the superconductor directly into the semiconducting material growth stack, depositing it in-situ in a molecular beam epitaxy system under high vacuum. We present a number of experiments on these hybrid heterostructures, demonstrating near unity interface transparency...

Irradiation-induced dimensional changes of fuel compacts and graphite sleeves of OGL-1 fuel assemblies

International Nuclear Information System (INIS)

Hayashi, Kimio; Minato, Kazuo; Kobayashi, Fumiaki; Tobita, Tsutomu; Kikuchi, Teruo; Kurobane, Shiro; Adachi, Mamoru; Fukuda, Kousaku

1988-06-01

Experimental data are summarized on irradiation-induced dimensional changes of fuel compacts and graphite sleeves of the first to ninth OGL-1 fuel assemblies. The range of fast-neutron fluence is up to 4 x 10 24 n/m 2 (E > 0.18 MeV); and that of irradiation temperature is 900 - 1400 deg C for fuel compacts and 800 - 1050 deg C for graphite sleeves. The dimensional change of the fuel compacts was shrinkage under these test conditions, and the shrinkage fraction increased almost linearly with fast-neutron fluence. The shrinkage fraction of the fuel compacts was larger by 20 % in the axial direction than in the radial direction. Influence of the irradiation temperature on the dimensional-change behavior of the fuel compacts was not observed clearly; presumably the influence was hidden by scatter of the data because of low level of the fast-neutron fluence and the resultant small dimensional changes. (author)

A two-dimensional, semi-analytic expansion method for nodal calculations

International Nuclear Information System (INIS)

Palmtag, S.P.

1995-08-01

Most modern nodal methods used today are based upon the transverse integration procedure in which the multi-dimensional flux shape is integrated over the transverse directions in order to produce a set of coupled one-dimensional flux shapes. The one-dimensional flux shapes are then solved either analytically or by representing the flux shape by a finite polynomial expansion. While these methods have been verified for most light-water reactor applications, they have been found to have difficulty predicting the large thermal flux gradients near the interfaces of highly-enriched MOX fuel assemblies. A new method is presented here in which the neutron flux is represented by a non-seperable, two-dimensional, semi-analytic flux expansion. The main features of this method are (1) the leakage terms from the node are modeled explicitly and therefore, the transverse integration procedure is not used, (2) the corner point flux values for each node are directly edited from the solution method, and a corner-point interpolation is not needed in the flux reconstruction, (3) the thermal flux expansion contains hyperbolic terms representing analytic solutions to the thermal flux diffusion equation, and (4) the thermal flux expansion contains a thermal to fast flux ratio term which reduces the number of polynomial expansion functions needed to represent the thermal flux. This new nodal method has been incorporated into the computer code COLOR2G and has been used to solve a two-dimensional, two-group colorset problem containing uranium and highly-enriched MOX fuel assemblies. The results from this calculation are compared to the results found using a code based on the traditional transverse integration procedure

The applications of a higher-dimensional Lie algebra and its decomposed subalgebras

International Nuclear Information System (INIS)

Yu Zhang; Zhang Yufeng

2009-01-01

With the help of invertible linear transformations and the known Lie algebras, a higher-dimensional 6 x 6 matrix Lie algebra sμ(6) is constructed. It follows a type of new loop algebra is presented. By using a (2 + 1)-dimensional partial-differential equation hierarchy we obtain the integrable coupling of the (2 + 1)-dimensional KN integrable hierarchy, then its corresponding Hamiltonian structure is worked out by employing the quadratic-form identity. Furthermore, a higher-dimensional Lie algebra denoted by E, is given by decomposing the Lie algebra sμ(6), then a discrete lattice integrable coupling system is produced. A remarkable feature of the Lie algebras sμ(6) and E is used to directly construct integrable couplings

The applications of a higher-dimensional Lie algebra and its decomposed subalgebras

Science.gov (United States)

Yu, Zhang; Zhang, Yufeng

2009-01-01

With the help of invertible linear transformations and the known Lie algebras, a higher-dimensional 6 × 6 matrix Lie algebra sμ(6) is constructed. It follows a type of new loop algebra is presented. By using a (2 + 1)-dimensional partial-differential equation hierarchy we obtain the integrable coupling of the (2 + 1)-dimensional KN integrable hierarchy, then its corresponding Hamiltonian structure is worked out by employing the quadratic-form identity. Furthermore, a higher-dimensional Lie algebra denoted by E, is given by decomposing the Lie algebra sμ(6), then a discrete lattice integrable coupling system is produced. A remarkable feature of the Lie algebras sμ(6) and E is used to directly construct integrable couplings. PMID:20084092

Three-dimensional reconstruction of functional brain images

International Nuclear Information System (INIS)

Inoue, Masato; Shoji, Kazuhiko; Kojima, Hisayoshi; Hirano, Shigeru; Naito, Yasushi; Honjo, Iwao

1999-01-01

We consider PET (positron emission tomography) measurement with SPM (Statistical Parametric Mapping) analysis to be one of the most useful methods to identify activated areas of the brain involved in language processing. SPM is an effective analytical method that detects markedly activated areas over the whole brain. However, with the conventional presentations of these functional brain images, such as horizontal slices, three directional projection, or brain surface coloring, makes understanding and interpreting the positional relationships among various brain areas difficult. Therefore, we developed three-dimensionally reconstructed images from these functional brain images to improve the interpretation. The subjects were 12 normal volunteers. The following three types of images were constructed: routine images by SPM, three-dimensional static images, and three-dimensional dynamic images, after PET images were analyzed by SPM during daily dialog listening. The creation of images of both the three-dimensional static and dynamic types employed the volume rendering method by VTK (The Visualization Toolkit). Since the functional brain images did not include original brain images, we synthesized SPM and MRI brain images by self-made C++ programs. The three-dimensional dynamic images were made by sequencing static images with available software. Images of both the three-dimensional static and dynamic types were processed by a personal computer system. Our newly created images showed clearer positional relationships among activated brain areas compared to the conventional method. To date, functional brain images have been employed in fields such as neurology or neurosurgery, however, these images may be useful even in the field of otorhinolaryngology, to assess hearing and speech. Exact three-dimensional images based on functional brain images are important for exact and intuitive interpretation, and may lead to new developments in brain science. Currently, the surface

Three-dimensional reconstruction of functional brain images

Energy Technology Data Exchange (ETDEWEB)

Inoue, Masato; Shoji, Kazuhiko; Kojima, Hisayoshi; Hirano, Shigeru; Naito, Yasushi; Honjo, Iwao [Kyoto Univ. (Japan)

1999-08-01

We consider PET (positron emission tomography) measurement with SPM (Statistical Parametric Mapping) analysis to be one of the most useful methods to identify activated areas of the brain involved in language processing. SPM is an effective analytical method that detects markedly activated areas over the whole brain. However, with the conventional presentations of these functional brain images, such as horizontal slices, three directional projection, or brain surface coloring, makes understanding and interpreting the positional relationships among various brain areas difficult. Therefore, we developed three-dimensionally reconstructed images from these functional brain images to improve the interpretation. The subjects were 12 normal volunteers. The following three types of images were constructed: routine images by SPM, three-dimensional static images, and three-dimensional dynamic images, after PET images were analyzed by SPM during daily dialog listening. The creation of images of both the three-dimensional static and dynamic types employed the volume rendering method by VTK (The Visualization Toolkit). Since the functional brain images did not include original brain images, we synthesized SPM and MRI brain images by self-made C++ programs. The three-dimensional dynamic images were made by sequencing static images with available software. Images of both the three-dimensional static and dynamic types were processed by a personal computer system. Our newly created images showed clearer positional relationships among activated brain areas compared to the conventional method. To date, functional brain images have been employed in fields such as neurology or neurosurgery, however, these images may be useful even in the field of otorhinolaryngology, to assess hearing and speech. Exact three-dimensional images based on functional brain images are important for exact and intuitive interpretation, and may lead to new developments in brain science. Currently, the surface

Forming three-dimensional closed shapes from two-dimensional soft ribbons by controlled buckling

Science.gov (United States)

Aoki, Michio; Juang, Jia-Yang

2018-02-01

Conventional manufacturing techniques-moulding, machining and casting-exist to produce three-dimensional (3D) shapes. However, these industrial processes are typically geared for mass production and are not directly applicable to residential settings, where inexpensive and versatile tools are desirable. Moreover, those techniques are, in general, not adequate to process soft elastic materials. Here, we introduce a new concept of forming 3D closed hollow shapes from two-dimensional (2D) elastic ribbons by controlled buckling. We numerically and experimentally characterize how the profile and thickness of the ribbon determine its buckled shape. We find a 2D master profile with which various elliptical 3D shapes can be formed. More complex natural and artificial hollow shapes, such as strawberry, hourglass and wheel, can also be achieved via strategic design and pattern engraving on the ribbons. The nonlinear response of the post-buckling regime is rationalized through finite-element analysis, which shows good quantitative agreement with experiments. This robust fabrication should complement conventional techniques and provide a rich arena for future studies on the mechanics and new applications of elastic hollow structures.

New hybrid lead iodides: From one-dimensional chain to two-dimensional layered perovskite structure

International Nuclear Information System (INIS)

Xiong, Kecai; Liu, Wei; Teat, Simon J.; An, Litao; Wang, Hao; Emge, Thomas J.; Li, Jing

2015-01-01

Two new hybrid lead halides (H 2 BDA)[PbI 4 ] (1) (H 2 BDA=1,4-butanediammonium dication) and (HNPEIM)[PbI 3 ] (2) (HNPEIM=N-​phenyl-ethanimidamidine cation) have been synthesized and structurally characterized. X-ray diffraction analyses reveal that compound 1 features a two-dimensional corner-sharing perovskite layer whereas compound 2 contains one-dimensional edge-sharing double chains. The N-​phenyl-ethanimidamidine cation within compound 2 was generated in-situ under solvothermal conditions. The optical absorption spectra collected at room temperature suggest that both compounds are semiconductors having direct band gaps, with estimated values of 2.64 and 2.73 eV for 1 and 2, respectively. Results from the density functional theory (DFT) calculations are consistent with the experimental data. Density of states (DOS) analysis reveals that in both compounds 1 and 2, the energy states in the valence band maximum region are iodine 5p atomic orbitals with a small contribution from lead 6s, while in the region of conduction band minimum, the major contributions are from the inorganic (Pb 6p atomic orbitals) and organic components (C and N 2p atomic orbitals) in compound 1 and 2, respectively. - Graphical abstract: Two new hybrid lead halides built on one-dimensional edge-sharing double chains and two-dimensional corner-sharing perovskite layers are synthesized and their structural and electronic properties are analyzed. - Highlights: • Two new hybrid lead iodides are designed, synthesized, and characterized. • They are closely related to, but different from, perovskite structures. • The electronic properties of both compounds are analyzed by DFT calculations

New hybrid lead iodides: From one-dimensional chain to two-dimensional layered perovskite structure

Energy Technology Data Exchange (ETDEWEB)

Xiong, Kecai; Liu, Wei [Department of Chemistry and Chemical Biology, Rutgers University, 610 Taylor Road, Piscataway, NJ 08854 (United States); Teat, Simon J. [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); An, Litao; Wang, Hao; Emge, Thomas J. [Department of Chemistry and Chemical Biology, Rutgers University, 610 Taylor Road, Piscataway, NJ 08854 (United States); Li, Jing, E-mail: jingli@rutgers.edu [Department of Chemistry and Chemical Biology, Rutgers University, 610 Taylor Road, Piscataway, NJ 08854 (United States)

2015-10-15

Two new hybrid lead halides (H{sub 2}BDA)[PbI{sub 4}] (1) (H{sub 2}BDA=1,4-butanediammonium dication) and (HNPEIM)[PbI{sub 3}] (2) (HNPEIM=N-​phenyl-ethanimidamidine cation) have been synthesized and structurally characterized. X-ray diffraction analyses reveal that compound 1 features a two-dimensional corner-sharing perovskite layer whereas compound 2 contains one-dimensional edge-sharing double chains. The N-​phenyl-ethanimidamidine cation within compound 2 was generated in-situ under solvothermal conditions. The optical absorption spectra collected at room temperature suggest that both compounds are semiconductors having direct band gaps, with estimated values of 2.64 and 2.73 eV for 1 and 2, respectively. Results from the density functional theory (DFT) calculations are consistent with the experimental data. Density of states (DOS) analysis reveals that in both compounds 1 and 2, the energy states in the valence band maximum region are iodine 5p atomic orbitals with a small contribution from lead 6s, while in the region of conduction band minimum, the major contributions are from the inorganic (Pb 6p atomic orbitals) and organic components (C and N 2p atomic orbitals) in compound 1 and 2, respectively. - Graphical abstract: Two new hybrid lead halides built on one-dimensional edge-sharing double chains and two-dimensional corner-sharing perovskite layers are synthesized and their structural and electronic properties are analyzed. - Highlights: • Two new hybrid lead iodides are designed, synthesized, and characterized. • They are closely related to, but different from, perovskite structures. • The electronic properties of both compounds are analyzed by DFT calculations.

Restoration of three-dimensional MR images degraded by rotational movements

International Nuclear Information System (INIS)

Wood, M.L.

1990-01-01

This paper describes a method to restore three-dimensional (3D) magnetic resonance (MR) images that have been degraded by rotational movements, such as head nodding by a restless patient. The technique for acquiring the 3D MR images includes additional MR signals, which provide one-dimensional (1D) and two-dimensional (2D) projections of anatomy. The 1D projections detect gross movements, and the 2D projections resolve displacements in one plane. The 2D projections are transformed from Cartesian coordinates to polar coordinates to identify rotation. A spatial transformation to reverse the rotation is applied to the imaging data after they have been Fourier transformed to resolve structures in the plane of rotation, but before the Fourier transform for the third direction

Two-dimensionally confined topological edge states in photonic crystals

International Nuclear Information System (INIS)

Barik, Sabyasachi; Miyake, Hirokazu; DeGottardi, Wade; Waks, Edo; Hafezi, Mohammad

2016-01-01

We present an all-dielectric photonic crystal structure that supports two-dimensionally confined helical topological edge states. The topological properties of the system are controlled by the crystal parameters. An interface between two regions of differing band topologies gives rise to topological edge states confined in a dielectric slab that propagate around sharp corners without backscattering. Three-dimensional finite-difference time-domain calculations show these edges to be confined in the out-of-plane direction by total internal reflection. Such nanoscale photonic crystal architectures could enable strong interactions between photonic edge states and quantum emitters. (paper)

Feature Screening for Ultrahigh Dimensional Categorical Data with Applications.

Science.gov (United States)

Huang, Danyang; Li, Runze; Wang, Hansheng

2014-01-01

Ultrahigh dimensional data with both categorical responses and categorical covariates are frequently encountered in the analysis of big data, for which feature screening has become an indispensable statistical tool. We propose a Pearson chi-square based feature screening procedure for categorical response with ultrahigh dimensional categorical covariates. The proposed procedure can be directly applied for detection of important interaction effects. We further show that the proposed procedure possesses screening consistency property in the terminology of Fan and Lv (2008). We investigate the finite sample performance of the proposed procedure by Monte Carlo simulation studies, and illustrate the proposed method by two empirical datasets.

A two-dimensional micro scanner integrated with a piezoelectric actuator and piezoresistors.

Science.gov (United States)

Zhang, Chi; Zhang, Gaofei; You, Zheng

2009-01-01

A compact two-dimensional micro scanner with small volume, large deflection angles and high frequency is presented and the two-dimensional laser scanning is achieved by specular reflection. To achieve large deflection angles, the micro scanner excited by a piezoelectric actuator operates in the resonance mode. The scanning frequencies and the maximum scanning angles of the two degrees of freedom are analyzed by modeling and simulation of the structure. For the deflection angle measurement, piezoresistors are integrated in the micro scanner. The appropriate directions and crystal orientations of the piezoresistors are designed to obtain the large piezoresistive coefficients for the high sensitivities. Wheatstone bridges are used to measure the deflection angles of each direction independently and precisely. The scanner is fabricated and packaged with the piezoelectric actuator and the piezoresistors detection circuits in a size of 28 mm×20 mm×18 mm. The experiment shows that the two scanning frequencies are 216.8 Hz and 464.8 Hz, respectively. By an actuation displacement of 10 μm, the scanning range of the two-dimensional micro scanner is above 26° × 23°. The deflection angle measurement sensitivities for two directions are 59 mV/deg and 30 mV/deg, respectively.

Terahertz computed tomography in three-dimensional using a pyroelectric array detector

Science.gov (United States)

Li, Bin; Wang, Dayong; Zhou, Xun; Rong, Lu; Huang, Haochong; Wan, Min; Wang, Yunxin

2017-05-01

Terahertz frequency range spans from 0.1 to 10 THz. Terahertz radiation can penetrate nonpolar materials and nonmetallic materials, such as plastics, wood, and clothes. Then the feature makes the terahertz imaging have important research value. Terahertz computed tomography makes use of the penetrability of terahertz radiation and obtains three-dimensional object projection data. In the paper, continuous-wave terahertz computed tomography with a pyroelectric array detectoris presented. Compared with scanning terahertz computed tomography, a pyroelectric array detector can obtain a large number of projection data in a short time, as the acquisition mode of the array pyroelectric detector omit the projection process on the vertical and horizontal direction. With the two-dimensional cross-sectional images of the object are obtained by the filtered back projection algorithm. The two side distance of the straw wall account for 80 pixels, so it multiplied by the pixel size is equal to the diameter of the straw about 6.4 mm. Compared with the actual diameter of the straw, the relative error is 6%. In order to reconstruct the three-dimensional internal structure image of the straw, the y direction range from 70 to 150 are selected on the array pyroelectric detector and are reconstructed by the filtered back projection algorithm. As the pixel size is 80 μm, the height of three-dimensional internal structure image of the straw is 6.48 mm. The presented system can rapidly reconstruct the three-dimensional object by using a pyroelectric array detector and explores the feasibility of on non-destructive evaluation and security testing.

Spectral dimensionality of random superconducting networks

International Nuclear Information System (INIS)

Day, A.R.; Xia, W.; Thorpe, M.F.

1988-01-01

We compute the spectral dimensionality d of random superconducting-normal networks by directly examining the low-frequency density of states at the percolation threshold. We find that d = 4.1 +- 0.2 and 5.8 +- 0.3 in two and three dimensions, respectively, which confirms the scaling relation d = 2d/(2-s/ν), where s is the superconducting exponent and ν the correlation-length exponent for percolation. We also consider the one-dimensional problem where scaling arguments predict, and our numerical simulations confirm, that d = 0. A simple argument provides an expression for the density of states of the localized high-frequency modes in this special case. We comment on the connection between our calculations and the ''termite'' problem of a random walker on a random superconducting-normal network and point out difficulties in inferring d from simulations of the termite problem

Ultra-refractive and extended-range one-dimensional photonic crystal superprisms

Science.gov (United States)

Ting, D. Z. Y.

2003-01-01

We describe theoretical analysis and design of one-dimensional photonic crystal prisms. We found that inside the photonic crystal, for frequencies near the band edges, light propagation direction is extremely sensitive to the variations in wavelength and incident angle.

Patterning two-dimensional free-standing surfaces with mesoporous conducting polymers

NARCIS (Netherlands)

Liu, Shaohua; Gordiichuk, Pavlo; Wu, Zhong-Shuai; Liu, Zhaoyang; Wei, Wei; Wagner, Manfred; Mohamed-Noriega, Nasser; Wu, Dongqing; Mai, Yiyong; Herrmann, Andreas; Müllen, Klaus; Feng, Xinliang

2015-01-01

The ability to pattern functional moieties with well-defined architectures is highly important in material science, nanotechnology and bioengineering. Although two-dimensional surfaces can serve as attractive platforms, direct patterning them in solution with regular arrays remains a major

Theory of equidistant three-dimensional radiance measurements with optical microprobes RID A-1977-2009

DEFF Research Database (Denmark)

FukshanskyKazarinova, N.; Fukshansky, L.; Kuhl, Morten

1996-01-01

Fiber-optic radiance microprobes, increasingly applied for measurements of internal light fields in living tissues, provide three-dimensional radiance distribution solids and radiant energy fluence rates at different depths of turbid samples. These data are, however, distorted because of an inher...... of application is presented. The limitations of this theory and the prospects for this approach are discussed....... of an inherent feature of optical fibers: nonuniform angular sensitivity. Because of this property a radiance microprobe during a single measurement partly underestimates light from the envisaged direction and partly senses light from other directions. A theory of three-dimensional equidistant radiance...

Three-dimensional closed-loop control of self-propelled microjets

NARCIS (Netherlands)

Khalil, I.S.M.; Magdanz, Veronika; Schmidt, Oliver S.; Sanchez, Samuel; Misra, Sarthak

2013-01-01

We demonstrate precise closed-loop control of microjets under the influence of the magnetic fields in three-dimensional (3D) space. For this purpose, we design a magnetic-based control system that directs the field lines towards reference positions. Microjets align along the controlled field lines

Global sensitivity analysis by polynomial dimensional decomposition

Energy Technology Data Exchange (ETDEWEB)

Rahman, Sharif, E-mail: rahman@engineering.uiowa.ed [College of Engineering, The University of Iowa, Iowa City, IA 52242 (United States)

2011-07-15

This paper presents a polynomial dimensional decomposition (PDD) method for global sensitivity analysis of stochastic systems subject to independent random input following arbitrary probability distributions. The method involves Fourier-polynomial expansions of lower-variate component functions of a stochastic response by measure-consistent orthonormal polynomial bases, analytical formulae for calculating the global sensitivity indices in terms of the expansion coefficients, and dimension-reduction integration for estimating the expansion coefficients. Due to identical dimensional structures of PDD and analysis-of-variance decomposition, the proposed method facilitates simple and direct calculation of the global sensitivity indices. Numerical results of the global sensitivity indices computed for smooth systems reveal significantly higher convergence rates of the PDD approximation than those from existing methods, including polynomial chaos expansion, random balance design, state-dependent parameter, improved Sobol's method, and sampling-based methods. However, for non-smooth functions, the convergence properties of the PDD solution deteriorate to a great extent, warranting further improvements. The computational complexity of the PDD method is polynomial, as opposed to exponential, thereby alleviating the curse of dimensionality to some extent.

Higher (odd dimensional quantum Hall effect and extended dimensional hierarchy

Directory of Open Access Journals (Sweden)

Kazuki Hasebe

2017-07-01

Full Text Available We demonstrate dimensional ladder of higher dimensional quantum Hall effects by exploiting quantum Hall effects on arbitrary odd dimensional spheres. Non-relativistic and relativistic Landau models are analyzed on S2k−1 in the SO(2k−1 monopole background. The total sub-band degeneracy of the odd dimensional lowest Landau level is shown to be equal to the winding number from the base-manifold S2k−1 to the one-dimension higher SO(2k gauge group. Based on the chiral Hopf maps, we clarify the underlying quantum Nambu geometry for odd dimensional quantum Hall effect and the resulting quantum geometry is naturally embedded also in one-dimension higher quantum geometry. An origin of such dimensional ladder connecting even and odd dimensional quantum Hall effects is illuminated from a viewpoint of the spectral flow of Atiyah–Patodi–Singer index theorem in differential topology. We also present a BF topological field theory as an effective field theory in which membranes with different dimensions undergo non-trivial linking in odd dimensional space. Finally, an extended version of the dimensional hierarchy for higher dimensional quantum Hall liquids is proposed, and its relationship to quantum anomaly and D-brane physics is discussed.

Direct energy recovery from helium ion beams by a beam direct converter with secondary electron suppressors

International Nuclear Information System (INIS)

Yoshikawa, K.; Yamamoto, Y.; Toku, H.; Kobayashi, A.; Okazaki, T.

1989-01-01

A 5-yr study of beam direct energy conversion was performed at the Kyoto University Institute of Atomic Energy to clarify the essential features of direct energy recovery from monoenergetic ion beams so that the performance characteristics of energy recovery can be predicted reasonably well by numerical calculations. The study used an improved version of an electrostatically electron-suppressed beam direct converter. Secondary electron suppressor grids were added, and a helium ion beam was used with typical parameters of 15.4 keV, 90 mA, and 100 ms. This paper presents a comparison of experimental results with numerical results by the two-dimensional Kyoto University Advanced Dart (KUAD) code, including evaluation of atomic processes

Magnetic anisotropy of two-dimensional nanostructures: Transition-metal triangular stripes

International Nuclear Information System (INIS)

Dorantes-Davila, J.; Villasenor-Gonzalez, P.; Pastor, G.M.

2005-01-01

The magnetic anisotropy energy (MAE) of one-dimensional stripes having infinite length and triangular lateral structure are investigated in the framework of a self-consistent tight-binding method. One observes discontinuous changes in the easy magnetization direction along the crossover from one to two dimensions. The MAE oscillates as a function of stripe width and depends strongly on the considered transition metal (TM). The MAE of the two-leg ladder is strongly reduced as compared to that of the monoatomic chain and the convergence to the two-dimensional limit is rather slow

Three-dimensional imaging of hidden objects using positron emission backscatter

International Nuclear Information System (INIS)

Lee, Dongwon; Cowee, Misa; Fenimore, Ed; Galassi, Mark; Looker, Quinn; Mcneil, Wendy V.; Stonehill, Laura; Wallace, Mark

2009-01-01

Positron emission backscatter imaging is a technique for interrogation and three-dimensional (3-D) reconstruction of hidden objects when we only have access to the objects from one side. Using time-of-flight differences in detected direct and backscattered positron-emitted photons, we construct 3-D images of target objects. Recently at Los Alamos National Laboratory, a fully three-dimensional imaging system has been built and the experimental results are discussed in this paper. Quantitative analysis of images reconstructed in both two- and three-dimensions are also presented.

Hypergraph-based anomaly detection of high-dimensional co-occurrences.

Science.gov (United States)

Silva, Jorge; Willett, Rebecca

2009-03-01

This paper addresses the problem of detecting anomalous multivariate co-occurrences using a limited number of unlabeled training observations. A novel method based on using a hypergraph representation of the data is proposed to deal with this very high-dimensional problem. Hypergraphs constitute an important extension of graphs which allow edges to connect more than two vertices simultaneously. A variational Expectation-Maximization algorithm for detecting anomalies directly on the hypergraph domain without any feature selection or dimensionality reduction is presented. The resulting estimate can be used to calculate a measure of anomalousness based on the False Discovery Rate. The algorithm has O(np) computational complexity, where n is the number of training observations and p is the number of potential participants in each co-occurrence event. This efficiency makes the method ideally suited for very high-dimensional settings, and requires no tuning, bandwidth or regularization parameters. The proposed approach is validated on both high-dimensional synthetic data and the Enron email database, where p > 75,000, and it is shown that it can outperform other state-of-the-art methods.

Topotactic transformations of superstructures: from thin films to two-dimensional networks to nested two-dimensional networks.

Science.gov (United States)

Guo, Chuan Fei; Cao, Sihai; Zhang, Jianming; Tang, Haoying; Guo, Shengming; Tian, Ye; Liu, Qian

2011-06-01

Design and synthesis of super-nanostructures is one of the key and prominent topics in nanotechnology. Here we propose a novel methodology for synthesizing complex hierarchical superstructures using sacrificial templates composed of ordered two-dimensional (2D) nanostructures through lattice-directed topotactic transformations. The fabricated superstructures are nested 2D orthogonal Bi(2)S(3) networks composed of nanorods. Further investigation indicates that the lattice matching between the product and sacrificial template is the dominant mechanism for the formation of the superstructures, which agrees well with the simulation results based on an anisotropic nucleation and growth analysis. Our approach may provide a promising way toward a lattice-directed nonlithographic nanofabrication technique for making functional porous nanoarchitectures and electronic devices. © 2011 American Chemical Society

Symmetry Analysis and Exact Solutions of (2+1)-Dimensional Sawada-Kotera Equation

International Nuclear Information System (INIS)

Zhi Hongyan; Zhang Hongqing

2008-01-01

Based on the symbolic computation system Maple, the infinite-dimensional symmetry group of the (2+1)-dimensional Sawada-Kotera equation is found by the classical Lie group method and the characterization of the group properties is given. The symmetry groups are used to perform the symmetry reduction. Moreover, with Lou's direct method that is based on Lax pairs, we obtain the symmetry transformations of the Sawada-Kotera and Konopelchenko-Dubrovsky equations, respectively.

Laser Direct Writing of Tree-Shaped Hierarchical Cones on a Superhydrophobic Film for High-Efficiency Water Collection.

Science.gov (United States)

Wang, Meng; Liu, Qian; Zhang, Haoran; Wang, Chuang; Wang, Lei; Xiang, Bingxi; Fan, Yongtao; Guo, Chuan Fei; Ruan, Shuangchen

2017-08-30

Directional water collection has stimulated a great deal of interest because of its potential applications in the field of microfluidics, liquid transportation, fog harvesting, and so forth. There have been some bio or bioinspired structures for directional water collection, from one-dimensional spider silk to two-dimensional star-like patterns to three-dimensional Nepenthes alata. Here we present a simple way for the accurate design and highly controllable driving of tiny droplets: by laser direct writing of hierarchical patterns with modified wettability and desired geometry on a superhydrophobic film, the patterned film can precisely and directionally drive tiny water droplets and dramatically improve the efficiency of water collection with a factor of ∼36 compared with the original superhydrophobic film. Such a patterned film might be an ideal platform for water collection from humid air and for planar microfluidics without tunnels.

Application of alternating current for dimensionally electrochemical machining

International Nuclear Information System (INIS)

Kacheev, M.K.; Kovalev, L.M.

1978-01-01

The results of comparative experimental investigations in dimensionally electrochemical machining of 1Kh18N9T steel using alternating and direct currents are presented. The effect of the electrolyte rate in the inter-electrode clearance, electrode voltage and oscillation amplitude of the electrode-tool on the metal output from the electrodes and the relief of the machined surface is studied. It is shown that the a.c. electrochemical machining permits to achieve the greater dimensional accuracy than the d.c. machining when choosing the proper voltage and electrolyte composition. It is connected with the fact that the prevailing part of the metal output is obtained in the impulse-asymmetrical regime when the inter-electrode clearance is minimum

A new method for information retrieval in two-dimensional grating-based X-ray phase contrast imaging

International Nuclear Information System (INIS)

Wang Zhi-Li; Gao Kun; Chen Jian; Ge Xin; Tian Yang-Chao; Wu Zi-Yu; Zhu Pei-Ping

2012-01-01

Grating-based X-ray phase contrast imaging has been demonstrated to be an extremely powerful phase-sensitive imaging technique. By using two-dimensional (2D) gratings, the observable contrast is extended to two refraction directions. Recently, we have developed a novel reverse-projection (RP) method, which is capable of retrieving the object information efficiently with one-dimensional (1D) grating-based phase contrast imaging. In this contribution, we present its extension to the 2D grating-based X-ray phase contrast imaging, named the two-dimensional reverse-projection (2D-RP) method, for information retrieval. The method takes into account the nonlinear contributions of two refraction directions and allows the retrieval of the absorption, the horizontal and the vertical refraction images. The obtained information can be used for the reconstruction of the three-dimensional phase gradient field, and for an improved phase map retrieval and reconstruction. Numerical experiments are carried out, and the results confirm the validity of the 2D-RP method

A rapid reliability estimation method for directed acyclic lifeline networks with statistically dependent components

International Nuclear Information System (INIS)

Kang, Won-Hee; Kliese, Alyce

2014-01-01

Lifeline networks, such as transportation, water supply, sewers, telecommunications, and electrical and gas networks, are essential elements for the economic and societal functions of urban areas, but their components are highly susceptible to natural or man-made hazards. In this context, it is essential to provide effective pre-disaster hazard mitigation strategies and prompt post-disaster risk management efforts based on rapid system reliability assessment. This paper proposes a rapid reliability estimation method for node-pair connectivity analysis of lifeline networks especially when the network components are statistically correlated. Recursive procedures are proposed to compound all network nodes until they become a single super node representing the connectivity between the origin and destination nodes. The proposed method is applied to numerical network examples and benchmark interconnected power and water networks in Memphis, Shelby County. The connectivity analysis results show the proposed method's reasonable accuracy and remarkable efficiency as compared to the Monte Carlo simulations

Analyzing three-dimensional position of region of interest using an image of contrast media using unilateral X-ray exposure

International Nuclear Information System (INIS)

Harauchi, Hajime; Gotou, Hiroshi; Tanooka, Masao

1994-01-01

Analyzing three-dimensional internal structure of object in an X-ray study is usually performed by using two or more of the incidents of an X-ray direction. In this report, we analyzed the three-dimensional position of tubes with a phantom by using both contrast media and imaging of one direction in the X-ray study. The concentration of the iodine in contrast media can be known by using the log-subtraction image of only the one-directional incident X-ray. Also the diameter of tube filled with contrast media is calculated by the concentration of iodine. So we can show the three-dimensional position of tubes geometrically, by the diameter of tube and the measured value of the film. We verified this method by an experiment according to the theory. (author)

Numerical studies of unsteady coherent structures and transport in two-dimensional flows

Energy Technology Data Exchange (ETDEWEB)

Hesthaven, J.S.

1995-08-01

The dynamics of unsteady two-dimensional coherent structures in various physical systems is studied through direct numerical solution of the dynamical equations using spectral methods. The relation between the Eulerian and the Lagrangian auto-correlation functions in two-dimensional homogeneous, isotropic turbulence is studied. A simple analytic expression for the Eulerian and Lagrangian auto-correlation function for the fluctuating velocity field is derived solely on the basis of the one-dimensional power spectrum. The long-time evolution of monopolar and dipolar vortices in anisotropic systems relevant for geophysics and plasma physics is studied by direct numerical solution. Transport properties and spatial reorganization of vortical structures are found to depend strongly on the initial conditions. Special attention is given to the dynamics of strong monopoles and the development of unsteady tripolar structures. The development of coherent structures in fluid flows, incompressible as well as compressible, is studied by novel numerical schemes. The emphasis is on the development of spectral methods sufficiently advanced as to allow for detailed and accurate studies of the self-organizing processes. (au) 1 ill., 94 refs.

Parallel alternating direction preconditioner for isogeometric simulations of explicit dynamics

KAUST Repository

Łoś, Marcin

2015-04-27

In this paper we present a parallel implementation of the alternating direction preconditioner for isogeometric simulations of explicit dynamics. The Alternating Direction Implicit (ADI) algorithm, belongs to the category of matrix-splitting iterative methods, was proposed almost six decades ago for solving parabolic and elliptic partial differential equations, see [1–4]. The new version of this algorithm has been recently developed for isogeometric simulations of two dimensional explicit dynamics [5] and steady-state diffusion equations with orthotropic heterogenous coefficients [6]. In this paper we present a parallel version of the alternating direction implicit algorithm for three dimensional simulations. The algorithm has been incorporated as a part of PETIGA an isogeometric framework [7] build on top of PETSc [8]. We show the scalability of the parallel algorithm on STAMPEDE linux cluster up to 10,000 processors, as well as the convergence rate of the PCG solver with ADI algorithm as preconditioner.

All-optical routing and switching for three-dimensional photonic circuitry

Science.gov (United States)

Keil, Robert; Heinrich, Matthias; Dreisow, Felix; Pertsch, Thomas; Tünnermann, Andreas; Nolte, Stefan; Christodoulides, Demetrios N.; Szameit, Alexander

2011-01-01

The ability to efficiently transmit and rapidly process huge amounts of data has become almost indispensable to our daily lives. It turned out that all-optical networks provide a very promising platform to deal with this task. Within such networks opto-optical switches, where light is directed by light, are a crucial building block for an effective operation. In this article, we present an experimental analysis of the routing and switching behaviour of light in two-dimensional evanescently coupled waveguide arrays of Y- and T-junction geometries directly inscribed into fused silica using ultrashort laser pulses. These systems have the fundamental advantage of supporting three-dimensional network topologies, thereby breaking the limitations on complexity associated with planar structures while maintaining a high dirigibility of the light. Our results show how such arrays can be used to control the flow of optical signals within integrated photonic circuits. PMID:22355612

Three-dimensional spin-3 theories based on general kinematical algebras

Energy Technology Data Exchange (ETDEWEB)

Bergshoeff, Eric [Van Swinderen Institute for Particle Physics and Gravity, University of Groningen,Nijenborgh 4, 9747 AG Groningen (Netherlands); Grumiller, Daniel; Prohazka, Stefan [Institute for Theoretical Physics, TU Wien,Wiedner Hauptstrasse 8-10/136, A-1040 Vienna (Austria); Rosseel, Jan [Albert Einstein Center for Fundamental Physics, University of Bern,Sidlerstrasse 5, 3012 Bern (Switzerland); Faculty of Physics, University of Vienna,Boltzmanngasse 5, A-1090 Vienna (Austria)

2017-01-25

We initiate the study of non- and ultra-relativistic higher spin theories. For sake of simplicity we focus on the spin-3 case in three dimensions. We classify all kinematical algebras that can be obtained by all possible Inönü-Wigner contraction procedures of the kinematical algebra of spin-3 theory in three dimensional (anti-) de Sitter space-time. We demonstrate how to construct associated actions of Chern-Simons type, directly in the ultra-relativistic case and by suitable algebraic extensions in the non-relativistic case. We show how to give these kinematical algebras an infinite-dimensional lift by imposing suitable boundary conditions in a theory we call “Carroll Gravity”, whose asymptotic symmetry algebra turns out to be an infinite-dimensional extension of the Carroll algebra.

The simulation of two-dimensional migration patterns - a novel approach

International Nuclear Information System (INIS)

Villar, Heldio Pereira

1997-01-01

A novel approach to the problem of simulation of two-dimensional migration of solutes in saturated soils is presented. In this approach, the two-dimensional advection-dispersion equation is solved by finite-differences in a stepwise fashion, by employing the one-dimensional solution first in the direction of flow and then perpendicularly, using the same time increment in both cases. As the results of this numerical model were to be verified against experimental results obtained by radioactive tracer experiments, an attenuation factor, to account for the contribution of the gamma rays emitted by the whole plume of tracer to the readings of the adopted radiation detectors, was introduced into the model. The comparison between experimental and simulated concentration contours showed good agreement, thus establishing the feasibility of the approach proposed herein. (author)

Three-dimensional simulation of vortex breakdown

Science.gov (United States)

Kuruvila, G.; Salas, M. D.

1990-01-01

The integral form of the complete, unsteady, compressible, three-dimensional Navier-Stokes equations in the conservation form, cast in generalized coordinate system, are solved, numerically, to simulate the vortex breakdown phenomenon. The inviscid fluxes are discretized using Roe's upwind-biased flux-difference splitting scheme and the viscous fluxes are discretized using central differencing. Time integration is performed using a backward Euler ADI (alternating direction implicit) scheme. A full approximation multigrid is used to accelerate the convergence to steady state.

Thermal conductivity in one-dimensional nonlinear systems

Science.gov (United States)

Politi, Antonio; Giardinà, Cristian; Livi, Roberto; Vassalli, Massimo

2000-03-01

Thermal conducitivity of one-dimensional nonlinear systems typically diverges in the thermodynamic limit, whenever the momentum is conserved (i.e. in the absence of interactions with an external substrate). Evidence comes from detailed studies of Fermi-Pasta-Ulam and diatomic Toda chains. Here, we discuss the first example of a one-dimensional system obeying Fourier law : a chain of coupled rotators. Numerical estimates of the thermal conductivity obtained by simulating a chain in contact with two thermal baths at different temperatures are found to be consistent with those ones based on linear response theory. The dynamics of the Fourier modes provides direct evidence of energy diffusion. The finiteness of the conductivity is traced back to the occurrence of phase-jumps. Our conclusions are confirmed by the analysis of two variants of the rotator model.

Comparison of two intraoral scanners based on three-dimensional surface analysis

Directory of Open Access Journals (Sweden)

Kyung-Min Lee

2018-02-01

Full Text Available Abstract Background This in vivo study evaluated the difference of two well-known intraoral scanners used in dentistry, namely iTero (Align Technology and TRIOS (3Shape. Methods Thirty-two participants underwent intraoral scans with TRIOS and iTero scanners, as well as conventional alginate impressions. The scans obtained with the two intraoral scanners were compared with each other and were also compared with the corresponding model scans by means of three-dimensional surface analysis. The average differences between the two intraoral scans on the surfaces were evaluated by color-mapping. The average differences in the three-dimensional direction between each intraoral scans and its corresponding model scan were calculated at all points on the surfaces. Results The average differences between the two intraoral scanners were 0.057 mm at the maxilla and 0.069 mm at the mandible. Color histograms showed that local deviations between the two scanners occurred in the posterior area. As for difference in the three-dimensional direction, there was no statistically significant difference between two scanners. Conclusions Although there were some deviations in visible inspection, there was no statistical significance between the two intraoral scanners.

The Particle inside a Ring: A Two-Dimensional Quantum Problem Visualized by Scanning Tunneling Microscopy

Science.gov (United States)

Ellison, Mark D.

2008-01-01

The one-dimensional particle-in-a-box model used to introduce quantum mechanics to students suffers from a tenuous connection to a real physical system. This article presents a two-dimensional model, the particle confined within a ring, that directly corresponds to observations of surface electrons in a metal trapped inside a circular barrier.…

Multi-dimensional database design and implementation of dam safety monitoring system

Directory of Open Access Journals (Sweden)

Zhao Erfeng

2008-09-01

Full Text Available To improve the effectiveness of dam safety monitoring database systems, the development process of a multi-dimensional conceptual data model was analyzed and a logic design was achieved in multi-dimensional database mode. The optimal data model was confirmed by identifying data objects, defining relations and reviewing entities. The conversion of relations among entities to external keys and entities and physical attributes to tables and fields was interpreted completely. On this basis, a multi-dimensional database that reflects the management and analysis of a dam safety monitoring system on monitoring data information has been established, for which factual tables and dimensional tables have been designed. Finally, based on service design and user interface design, the dam safety monitoring system has been developed with Delphi as the development tool. This development project shows that the multi-dimensional database can simplify the development process and minimize hidden dangers in the database structure design. It is superior to other dam safety monitoring system development models and can provide a new research direction for system developers.

Topological superconductor in quasi-one-dimensional Tl2 -xMo6Se6

Science.gov (United States)

Huang, Shin-Ming; Hsu, Chuang-Han; Xu, Su-Yang; Lee, Chi-Cheng; Shiau, Shiue-Yuan; Lin, Hsin; Bansil, Arun

2018-01-01

We propose that the quasi-one-dimensional molybdenum selenide compound Tl2 -xMo6Se6 is a time-reversal-invariant topological superconductor induced by intersublattice pairing, even in the absence of spin-orbit coupling (SOC). No noticeable change in superconductivity is observed in Tl-deficient (0 ≤x ≤0.1 ) compounds. At weak SOC, the superconductor prefers the triplet d vector lying perpendicular to the chain direction and two-dimensional E2 u symmetry, which is driven to a nematic order by spontaneous rotation symmetry breaking. The locking energy of the d vector is estimated to be weak and hence the proof of its direction would rely on tunneling or phase-sensitive measurements.

Four and five dimensional radiotherapy with reference to prostate cancer - definitions, state of the art and further directions - an overview

Energy Technology Data Exchange (ETDEWEB)

Lennernaes, Bo (Dept. of Oncology, Sahlgrenska Hospital and Academy, Univ. of Gothenburg, Gothenburg (Sweden)), e-mail: bo.lennernas@telia.com; Castellanos, Enrique; Nilsson, Sten; Levitt, Seymour (Dept. of Oncology/Pathology, Karolinska Univ. Hospital and Institutet, Stockholm (Sweden))

2011-06-15

Radiotherapy (RT) always requires a compromise between tumor control and normal tissue side-effects. Technical innovation in radiation therapy (RT), such as three dimensional RT, is now established. Concerning prostate cancer (PC), it is reasonable to assume that RT of PC will increase in the future. The combination of small margins, a movable target (prostate), few fractions and high doses will probably demand dynamically positioning systems and in real time. This is called four dimensional radiotherapy (4DRT). Moreover, biological factors must be included in new treatments such as hypofractionation schedules. This new era is called five dimensional radiotherapy, 5DRT. In this paper we discuss new concepts in RT in respect to PC

Observation of hidden Fermi surface nesting in a two dimensional conductor

International Nuclear Information System (INIS)

Breuer, K.; Stagerescu, C.; Smith, K.E.; Greenblatt, M.; Ramanujachary, K.

1996-01-01

We report the first direct measurement of hidden Fermi surface nesting in a two dimensional conductor. The system studied was Na 0.9 Mo 6 O 17 , and the measured Fermi surface consists of electron and hole pockets that can be combined to form sets of pseudo-one-dimensional Fermi surfaces, exhibiting the nesting necessary to drive a Peierls transition to a charge density wave state. The observed nesting vector is shown to be in excellent agreement with theory. copyright 1996 The American Physical Society

A non-Abelian SO(8) monopole as generalization of Dirac-Yang monopoles for a 9-dimensional space

International Nuclear Information System (INIS)

Le, Van-Hoang; Nguyen, Thanh-Son

2011-01-01

We establish an explicit form of a non-Abelian SO(8) monopole in a 9-dimensional space and show that it is indeed a direct generalization of Dirac and Yang monopoles. Using the generalized Hurwitz transformation, we have found a connection between a 16-dimensional harmonic oscillator and a 9-dimensional hydrogenlike atom in the field of the SO(8) monopole (MICZ-Kepler problem). Using the built connection the group of dynamical symmetry of the 9-dimensional MICZ-Kepler problem is found as SO(10, 2).

A two-dimensional laser-wire scanner for electron accelerators

Energy Technology Data Exchange (ETDEWEB)

Bosco, A. [Physics Department John Adams Institute for Accelerator Science at Royal Holloway, University of London, Egham, Surrey TW20 0EX (United Kingdom)], E-mail: alessio.bosco@rhul.ac.uk; Price, M.T.; Blair, G.A.; Boogert, S.T.; Boorman, G.; Malton, S.; Driouichi, C. [Physics Department John Adams Institute for Accelerator Science at Royal Holloway, University of London, Egham, Surrey TW20 0EX (United Kingdom); Kamps, T. [Berliner Elektronenspeicherring, Gesellschaft fur Synchrotronstrahlung, Albert Einstein-Str. 15, 12489 Berlin (Germany); Poirier, F.; Balewski, K.; Elsen, E.; Gharibyan, V.; Lewin, H.-C.; Schreiber, S.; Walker, N.; Wittenburg, K. [Deutsches Elektronen-Synchrotron, Notkestrasse 85, 22607 Hamburg (Germany)

2008-07-21

A two-dimensional laser-wire scanner capable of measuring the transverse charge profiles of an electron (or positron) bunch has been constructed at the PETRA accelerator in DESY. The development of the system is explained in this paper, along with descriptions of its photon detector and laser system. Results of transverse profile scans are presented for both horizontal and vertical directions. The measurement error is 1.3% from a multi-scan measurement in the vertical direction, where single scans can be performed in less than 50 s.

A three-dimensional kinematic model for the dissolution of crystals

Science.gov (United States)

Tellier, C. R.

1989-06-01

The two-dimensional kinematic theory developed by Frank is extended into three dimensions. It is shown that the theoretical equations for the propagation vector associated with the displacement of a moving surface element can be directly derived from the polar equation of the slowness surface.

A Two-Dimensional Micro Scanner Integrated with a Piezoelectric Actuator and Piezoresistors

Directory of Open Access Journals (Sweden)

Zheng You

2009-01-01

Full Text Available A compact two-dimensional micro scanner with small volume, large deflection angles and high frequency is presented and the two-dimensional laser scanning is achieved by specular reflection. To achieve large deflection angles, the micro scanner excited by a piezoelectric actuator operates in the resonance mode. The scanning frequencies and the maximum scanning angles of the two degrees of freedom are analyzed by modeling and simulation of the structure. For the deflection angle measurement, piezoresistors are integrated in the micro scanner. The appropriate directions and crystal orientations of the piezoresistors are designed to obtain the large piezoresistive coefficients for the high sensitivities. Wheatstone bridges are used to measure the deflection angles of each direction independently and precisely. The scanner is fabricated and packaged with the piezoelectric actuator and the piezoresistors detection circuits in a size of 28 mm×20 mm×18 mm. The experiment shows that the two scanning frequencies are 216.8 Hz and 464.8 Hz, respectively. By an actuation displacement of 10 μm, the scanning range of the two-dimensional micro scanner is above 26º × 23º. The deflection angle measurement sensitivities for two directions are 59 mV/deg and 30 mV/deg, respectively.

One-way mode transmission in one-dimensional phononic crystal plates

Science.gov (United States)

Zhu, Xuefeng; Zou, Xinye; Liang, Bin; Cheng, Jianchun

2010-12-01

We investigate theoretically the band structures of one-dimensional phononic crystal (PC) plates with both antisymmetric and symmetric structures, and show how unidirectional transmission behavior can be obtained for either antisymmetric waves (A modes) or symmetric waves (S modes) by exploiting mode conversion and selection in the linear plate systems. The theoretical approach is illustrated for one PC plate example where unidirectional transmission behavior is obtained in certain frequency bands. Employing harmonic frequency analysis, we numerically demonstrate the one-way mode transmission for the PC plate with finite superlattice by calculating the steady-state displacement fields under A modes source (or S modes source) in forward and backward direction, respectively. The results show that the incident waves from A modes source (or S modes source) are transformed into S modes waves (or A modes waves) after passing through the superlattice in the forward direction and the Lamb wave rejections in the backward direction are striking with a power extinction ratio of more than 1000. The present structure can be easily extended to two-dimensional PC plate and efficiently encourage practical studies of experimental realization which is believed to have much significance for one-way Lamb wave mode transmission.

Angular interpolations and splice options for three-dimensional transport computations

International Nuclear Information System (INIS)

Abu-Shumays, I.K.; Yehnert, C.E.

1996-01-01

New, accurate and mathematically rigorous angular Interpolation strategies are presented. These strategies preserve flow and directionality separately over each octant of the unit sphere, and are based on a combination of spherical harmonics expansions and least squares algorithms. Details of a three-dimensional to three-dimensional (3-D to 3-D) splice method which utilizes the new angular interpolations are summarized. The method has been implemented in a multidimensional discrete ordinates transport computer program. Various features of the splice option are illustrated by several applications to a benchmark Dog-Legged Void Neutron (DLVN) streaming and transport experimental assembly

Intra-connected three-dimensionally isotropic bulk negative index photonic metamaterial

International Nuclear Information System (INIS)

Guney, Durdu; Koschny, Thomas; Soukoulis, Costas

2010-01-01

Isotropic negative index metamaterials (NIMs) are highly desired, particularly for the realization of ultra-high resolution lenses. However, existing isotropic NIMs function only two-dimensionally and cannot be miniaturized beyond microwaves. Direct laser writing processes can be a paradigm shift toward the fabrication of three-dimensionally (3D) isotropic bulk optical metamaterials, but only at the expense of an additional design constraint, namely connectivity. Here, we demonstrate with a proof-of-principle design that the requirement connectivity does not preclude fully isotropic left-handed behavior. This is an important step towards the realization of bulk 3D isotropic NIMs at optical wavelengths.

Assembly of multiple cell gradients directed by three-dimensional microfluidic channels.

Science.gov (United States)

Li, Yiwei; Feng, Xiaojun; Wang, Yachao; Du, Wei; Chen, Peng; Liu, Chao; Liu, Bi-Feng

2015-08-07

Active control over the cell gradient is essential for understanding biological systems and the reconstitution of the functionality of many types of tissues, particularly for organ-on-a-chip. Here, we propose a three-dimensional (3D) microfluidic strategy for generating controllable cell gradients. In this approach, a homogeneous cell suspension is loaded into a 3D stair-shaped PDMS microchannel to generate a cell gradient within 10 min by sedimentation. We demonstrate that cell gradients of various profiles (exponential and piecewise linear) can be achieved by precisely controlling the height of each layer during the fabrication. With sequential seeding, we further demonstrate the generation of two overlapping cell gradients on the same glass substrate with pre-defined designs. The cell gradient-based QD cytotoxicity assay also demonstrated that cell behaviors and resistances were regulated by the changes in cell density. These results reveal that the proposed 3D microfluidic strategy provides a simple and versatile means for establishing controllable gradients in cell density, opening up a new avenue for reconstructing functional tissues.

Lip Movement Exaggerations during Infant-Directed Speech

Science.gov (United States)

Green, Jordan R.; Nip, Ignatius S. B.; Wilson, Erin M.; Mefferd, Antje S.; Yunusova, Yana

2010-01-01

Purpose: Although a growing body of literature has identified the positive effects of visual speech on speech and language learning, oral movements of infant-directed speech (IDS) have rarely been studied. This investigation used 3-dimensional motion capture technology to describe how mothers modify their lip movements when talking to their…

Dynamics of vortex interactions in two-dimensional flows

DEFF Research Database (Denmark)

Juul Rasmussen, J.; Nielsen, A.H.; Naulin, V.

2002-01-01

The dynamics and interaction of like-signed vortex structures in two dimensional flows are investigated by means of direct numerical solutions of the two-dimensional Navier-Stokes equations. Two vortices with distributed vorticity merge when their distance relative to their radius, d/R-0l. is below...... a critical value, a(c). Using the Weiss-field, a(c) is estimated for vortex patches. Introducing an effective radius for vortices with distributed vorticity, we find that 3.3 ... is effectively producing small scale structures and the relation to the enstrophy "cascade" in developed 2D turbulence is discussed. The influence of finite viscosity on the merging is also investigated. Additionally, we examine vortex interactions on a finite domain, and discuss the results in connection...

Three-dimensional Bragg diffraction in growth-disordered opals

Science.gov (United States)

Baryshev, A. V.; Kaplyanskii, Alexander A.; Kosobukin, Vladimir A.; Limonov, M. F.; Samusev, K. B.; Usvyat, D. E.

2003-06-01

After artificial opals as well as opal-based infilled and inverted composites are considered to be promising representatives of photonic crystal materials. Earlier, photonic stop gaps in opals were studied mainly in transmission or specular reflection geometries corresponding to "one-dimensional" Bragg diffraction. On the contrary, this work was aimed at observing the typical patterns of optical Bragg diffraction in which phenomenon opal crystal structure acts as a three-dimensional diffraction grating. Although our experiments were performed for artificial opals possessing unavoidable imperfections a well-pronounced diffraction peaks were observed characteristic of a crystal structure. Each of the diffraction maxima reveals a photonic stop gap in the specified direction, while the spectral width of the peak is a measure of the photonic stop gap width.

Two-dimensional atom localization via Raman-driven coherence

Energy Technology Data Exchange (ETDEWEB)

Rahmatullah,; Qamar, Sajid, E-mail: sajid_qamar@comsats.edu.pk

2014-02-07

A scheme for two-dimensional (2D) atom localization via Raman-driven coherence in a four-level diamond-configuration system is suggested. The atom interacts with two orthogonal standing-wave fields where each standing-wave field is constructed from the superposition of the two-standing wave fields along the corresponding directions. Due to the position-dependent atom–field interaction, the frequency of the spontaneously emitted photon carries the position information about the atom. We investigate the effect of the detunings and phase shifts associated with standing-wave fields. Unique position information of the single atom is obtained by properly adjusting the system parameters. This is an extension of our previous proposal for one-dimensional atom localization via Raman-driven coherence.

Wetting characteristics of 3-dimensional nanostructured fractal surfaces

Science.gov (United States)

Davis, Ethan; Liu, Ying; Jiang, Lijia; Lu, Yongfeng; Ndao, Sidy

2017-01-01

This article reports the fabrication and wetting characteristics of 3-dimensional nanostructured fractal surfaces (3DNFS). Three distinct 3DNFS surfaces, namely cubic, Romanesco broccoli, and sphereflake were fabricated using two-photon direct laser writing. Contact angle measurements were performed on the multiscale fractal surfaces to characterize their wetting properties. Average contact angles ranged from 66.8° for the smooth control surface to 0° for one of the fractal surfaces. The change in wetting behavior was attributed to modification of the interfacial surface properties due to the inclusion of 3-dimensional hierarchical fractal nanostructures. However, this behavior does not exactly obey existing surface wetting models in the literature. Potential applications for these types of surfaces in physical and biological sciences are also discussed.

Acyclic Cucurbit[n]uril-Type Molecular Container Enables Systemic Delivery of Effective Doses of Albendazole for Treatment of SK-OV-3 Xenograft Tumors.

Science.gov (United States)

Hettiarachchi, Gaya; Samanta, Soumen K; Falcinelli, Shane; Zhang, Ben; Moncelet, Damien; Isaacs, Lyle; Briken, Volker

2016-03-07

Approximately, 40-70% of active pharmaceutical ingredients (API) are severely limited by their extremely poor aqueous solubility, and consequently, there is a high demand for excipients that can be used to formulate clinically relevant doses of these drug candidates. Here, proof-of-concept studies demonstrate the potential of our recently discovered acyclic cucurbit[n]uril-type molecular container Motor1 (M1) as a solubilizing agent for insoluble drugs. M1 did not induce significant rates of mutations in various Salmonella typhimurium test strains during the Ames test, suggesting low genotoxicity. M1 also has low risk of causing cardiac toxicity in humans since it did not inhibit the human Ether-à-go-go-Related Gene channel as tested on transfected CHO cell lines via patch clamp analysis. Albendazole (ABZ) is a widely used antihelminthic agent but that has also shown promising efficacy against cancerous cells in vitro. However, due to its low aqueous solubility (2.7 μM) and poor pharmacokinetics, ABZ is clinically limited as an anticancer agent. Here we investigated the potential of M1 as a solubilizing excipient for ABZ formulation. A pharmacokinetic study indicated that ABZ escapes the peritoneal cavity resulting in 78% absolute bioavailability, while its active intermediate metabolite, albendazole sulfoxide, achieved 43% absolute bioavailability. The daily dosing of 681 mg/kg M1 complexed with 3.2 mg/kg of ABZ for 14 days did not result in significant weight loss or pathology in Swiss Webster mice. In vivo efficacy studies using this M1·ABZ inclusion complex showed significant decreases in tumor growth rates and increases in survival of mice bearing SK-OV-3 xenograft tumors. In conclusion, we provide substantial new evidence demonstrating that M1 is a safe and efficient excipient that enables in vivo parenteral delivery of poorly water-soluble APIs.

Quasi-one-dimensional Hall physics in the Harper–Hofstadter–Mott model

Science.gov (United States)

Kozarski, Filip; Hügel, Dario; Pollet, Lode

2018-04-01

We study the ground-state phase diagram of the strongly interacting Harper–Hofstadter–Mott model at quarter flux on a quasi-one-dimensional lattice consisting of a single magnetic flux quantum in y-direction. In addition to superfluid phases with various density patterns, the ground-state phase diagram features quasi-one-dimensional analogs of fractional quantum Hall phases at fillings ν = 1/2 and 3/2, where the latter is only found thanks to the hopping anisotropy and the quasi-one-dimensional geometry. At integer fillings—where in the full two-dimensional system the ground-state is expected to be gapless—we observe gapped non-degenerate ground-states: at ν = 1 it shows an odd ‘fermionic’ Hall conductance, while the Hall response at ν = 2 consists of the transverse transport of a single particle–hole pair, resulting in a net zero Hall conductance. The results are obtained by exact diagonalization and in the reciprocal mean-field approximation.

Three-dimensional demonstration of liver and spleen by computer graphics technique

International Nuclear Information System (INIS)

Kashiwagi, Toru; Azuma, Masayoshi; Katayama, Kazuhiro; Yoshioka, Hiroaki; Ishizu, Hiromi; Mitsutani, Natsuki; Koizumi, Takao; Takayama, Ichiro

1987-01-01

Three-dimensional demonstration system of the liver and spleen has been developed using computer graphics technique. Three-dimensional models were constructed from CT images of the organ surface. The three-dimensional images were displayed as wire-frame and/or solid models on the color CRT. The anatomical surface of the liver and spleen was realistically viewed from any direction. In liver cirrhosis, atrophy of the right lobe, hypertrophy of the left lobe and splenomegaly were displayed vividly. The liver and hepatoma were displayed as wire-frame and solid models respectively on the same image. This combined display clarified the intrahepatic location of hepatoma together with configuration of liver and hepatoma. Furthermore, superimposed display of three dimensional models and celiac angiogram enabled us to understand the location and configuration of lesions more easily than the original CT data or angiogram alone. Therefore, it is expected that this system is clinically useful for noninvasive evaluation of patho-morphological changes of the liver and spleen. (author)

The simulation of two-dimensional migration patterns - a novel approach

Energy Technology Data Exchange (ETDEWEB)

Villar, Heldio Pereira [Universidade de Pernambuco, Recife, PE (Brazil). Escola Politecnica]|[Centro Regional de Ciencias Nucleares, Recife, PE (Brazil)

1997-12-31

A novel approach to the problem of simulation of two-dimensional migration of solutes in saturated soils is presented. In this approach, the two-dimensional advection-dispersion equation is solved by finite-differences in a stepwise fashion, by employing the one-dimensional solution first in the direction of flow and then perpendicularly, using the same time increment in both cases. As the results of this numerical model were to be verified against experimental results obtained by radioactive tracer experiments, an attenuation factor, to account for the contribution of the gamma rays emitted by the whole plume of tracer to the readings of the adopted radiation detectors, was introduced into the model. The comparison between experimental and simulated concentration contours showed good agreement, thus establishing the feasibility of the approach proposed herein. (author) 6 refs., 6 figs.

Direct numerical simulations of flow and heat transfer over a circular cylinder at Re = 2000

NARCIS (Netherlands)

Vidya, Mahening Citra; Beishuizen, N.A.; van der Meer, Theodorus H.

2016-01-01

Unsteady direct numerical simulations of the flow around a circular cylinder have been performed at Re = 2000. Both two-dimensional and three-dimensional simulations were validated with laminar cold flow simulations and experiments. Heat transfer simulations were carried out and the time-averaged

The dimensional reduction in a multi-dimensional cosmology

International Nuclear Information System (INIS)

Demianski, M.; Golda, Z.A.; Heller, M.; Szydlowski, M.

1986-01-01

Einstein's field equations are solved for the case of the eleven-dimensional vacuum spacetime which is the product R x Bianchi V x T 7 , where T 7 is a seven-dimensional torus. Among all possible solutions, the authors identify those in which the macroscopic space expands and the microscopic space contracts to a finite size. The solutions with this property are 'typical' within the considered class. They implement the idea of a purely dynamical dimensional reduction. (author)

One and two dimensional simulations on beat wave acceleration

International Nuclear Information System (INIS)

Mori, W.; Joshi, C.; Dawson, J.M.; Forslund, D.W.; Kindel, J.M.

1984-01-01

Recently there has been considerable interest in the use of fast-large-amplitude plasma waves as the basis for a high energy particle accelerator. In these schemes, lasers are used to create the plasma wave. To date the few simulation studies on this subject have been limited to one-dimensional, short rise time simulations. Here the authors present results from simulations in which more realistic parameters are used. In addition, they present the first two dimensional simulations on this subject. One dimensional simulations on a 2 1/2-D relativistic electromagnetic particle code, in which only a few cells were used in one direction, on colinear optical mixing are presented. In these simulations the laser rise time, laser intensity, plasma density, plasma temperature and system size were varied. The simulations indicate that the theory of Rosenbluth and Liu is applicable over a wide range of parameters. In addition, simulations with a DC magnetic field are presented in order to study the ''Surfatron'' concept

Algorithms to estimate the rose of directions of a spatial fibre system

DEFF Research Database (Denmark)

Kiderlen, Markus; Pfrang, A.

2005-01-01

The directional measure (which is up to normalization the rose of directions) is used to quantify anisotropy of stationary fibre processes in three-dimensional space. There exist a large number of approaches to estimate this measure from the rose of intersections (which is the mean number...

A high-speed computerized tomography image reconstruction using direct two-dimensional Fourier transform method

International Nuclear Information System (INIS)

Niki, Noboru; Mizutani, Toshio; Takahashi, Yoshizo; Inouye, Tamon.

1983-01-01

The nescessity for developing real-time computerized tomography (CT) aiming at the dynamic observation of organs such as hearts has lately been advocated. It is necessary for its realization to reconstruct the images which are markedly faster than present CTs. Although various reconstructing methods have been proposed so far, the method practically employed at present is the filtered backprojection (FBP) method only, which can give high quality image reconstruction, but takes much computing time. In the past, the two-dimensional Fourier transform (TFT) method was regarded as unsuitable to practical use because the quality of images obtained was not good, in spite of the promising method for high speed reconstruction because of its less computing time. However, since it was revealed that the image quality by TFT method depended greatly on interpolation accuracy in two-dimensional Fourier space, the authors have developed a high-speed calculation algorithm that can obtain high quality images by pursuing the relationship between the image quality and the interpolation method. In this case, radial data sampling points in Fourier space are increased to β-th power of 2 times, and the linear or spline interpolation is used. Comparison of this method with the present FBP method resulted in the conclusion that the image quality is almost the same in practical image matrix, the computational time by TFT method becomes about 1/10 of FBP method, and the memory capacity also reduces by about 20 %. (Wakatsuki, Y.)

Reconstruction of the electron momentum distribution from a set of directional Compton profiles

International Nuclear Information System (INIS)

Hansen, N.K.

1980-12-01

A method is described in which the 3-dimensional one-electron momentum density distribution is obtained from a series of directional Compton profiles measured on single crystals; a directional Compton profile being the projection of the momentum density onto a line through the origin. The procedure consists of 1-dimensional Fourier transformations of the individual profiles. The Fourier transformed Compton profiles are fitted by a finite expansion in lattice harmonic functions, and the momentum density is finally obtained by a 3-dimensional Fourier transform. The effect of statistical errors are derived both for the momentum density and its Fourier transform. The problem of how to carry out the measurements in an optimal way has been approached and suggestions made. A computer program for calculation of momentum density and error distributions have been listed in an appendix. (orig.)

About the problem of generating three-dimensional pseudo-random points.

Science.gov (United States)

Carpintero, D. D.

The author demonstrates that a popular pseudo-random number generator is not adequate in some circumstances to generate n-dimensional random points, n > 2. This problem is particularly noxious when direction cosines are generated. He proposes several soultions, among them a good generator that satisfies all statistical criteria.

Directional wave spectra off southeast coast of Tamil Nadu

Digital Repository Service at National Institute of Oceanography (India)

SanilKumar, V.; Deo, M.C.; Anand, N.M.; Gowthaman, R.

directional spreading. A well established way to describe the energy content in an irregular wind generated surface wave assumes superposition of linear waves and the two dimensional energy spectrum can be conveniently expressed as a product of the one...

Three dimensional illustrating - three-dimensional vision and deception of sensibility

Directory of Open Access Journals (Sweden)

Anita Gánóczy

2009-03-01

Full Text Available The wide-spread digital photography and computer use gave the opportunity for everyone to make three-dimensional pictures and to make them public. The new opportunities with three-dimensional techniques give chance for the birth of new artistic photographs. We present in detail the biological roots of three-dimensional visualization, the phenomena of movement parallax, which can be used efficiently in making three-dimensional graphics, the Zöllner- and Corridor-illusion. There are present in this paper the visual elements, which contribute to define a plane two-dimensional image in three-dimension: coherent lines, the covering, the measurement changes, the relative altitude state, the abatement of detail profusion, the shadings and the perspective effects of colors.

A comparative study of three-dimensional reconstructive images of temporomandibular joint using computed tomogram

International Nuclear Information System (INIS)

Lim, Suk Young; Koh, Kwang Joon

1993-01-01

The purpose of this study was to clarify the spatial relationship of temporomandibular joint and to an aid in the diagnosis of temporomandibular disorder. For this study, three-dimensional images of normal temporomandibular joint were reconstructed by computer image analysis system and three-dimensional reconstructive program integrated in computed tomography. The obtained results were as follows : 1. Two-dimensional computed tomograms had the better resolution than three dimensional computed tomograms in the evaluation of bone structure and the disk of TMJ. 2. Direct sagittal computed tomograms and coronal computed tomograms had the better resolution in the evaluation of the disk of TMJ. 3. The positional relationship of the disk could be visualized, but the configuration of the disk could not be clearly visualized on three-dimensional reconstructive CT images. 4. Three-dimensional reconstructive CT images had the smoother margin than three-dimensional images reconstructed by computer image analysis system, but the images of the latter had the better perspective. 5. Three-dimensional reconstructive images had the better spatial relationship of the TMJ articulation, and the joint space were more clearly visualized on dissection images.

Hyper dimensional phase-space solver and its application to laser-matter

Energy Technology Data Exchange (ETDEWEB)

Kondoh, Yoshiaki; Nakamura, Takashi; Yabe, Takashi [Department of Energy Sciences, Tokyo Institute of Technology, Yokohama, Kanagawa (Japan)

2000-03-01

A new numerical scheme for solving the hyper-dimensional Vlasov-Poisson equation in phase space is described. At each time step, the distribution function and its first derivatives are advected in phase space by the Cubic Interpolated Propagation (CIP) scheme. Although a cell within grid points is interpolated by a cubic-polynomial, any matrix solutions are not required. The scheme guarantees the exact conservation of the mass. The numerical results show good agreement with the theory. Even if we reduce the number of grid points in the v-direction, the scheme still gives stable, accurate and reasonable results with memory storage comparable to particle simulations. Owing to this fact, the scheme has succeeded to be generalized in a straightforward way to deal with the six-dimensional, or full-dimensional problems. (author)

Hyper dimensional phase-space solver and its application to laser-matter

International Nuclear Information System (INIS)

Kondoh, Yoshiaki; Nakamura, Takashi; Yabe, Takashi

2000-01-01

A new numerical scheme for solving the hyper-dimensional Vlasov-Poisson equation in phase space is described. At each time step, the distribution function and its first derivatives are advected in phase space by the Cubic Interpolated Propagation (CIP) scheme. Although a cell within grid points is interpolated by a cubic-polynomial, any matrix solutions are not required. The scheme guarantees the exact conservation of the mass. The numerical results show good agreement with the theory. Even if we reduce the number of grid points in the v-direction, the scheme still gives stable, accurate and reasonable results with memory storage comparable to particle simulations. Owing to this fact, the scheme has succeeded to be generalized in a straightforward way to deal with the six-dimensional, or full-dimensional problems. (author)

Four-dimensional Microscope-Integrated Optical Coherence Tomography to Visualize Suture Depth in Strabismus Surgery.

Science.gov (United States)

Pasricha, Neel D; Bhullar, Paramjit K; Shieh, Christine; Carrasco-Zevallos, Oscar M; Keller, Brenton; Izatt, Joseph A; Toth, Cynthia A; Freedman, Sharon F; Kuo, Anthony N

2017-02-14

The authors report the use of swept-source microscope-integrated optical coherence tomography (SS-MIOCT), capable of live four-dimensional (three-dimensional across time) intraoperative imaging, to directly visualize suture depth during lateral rectus resection. Key surgical steps visualized in this report included needle depth during partial and full-thickness muscle passes along with scleral passes. [J Pediatr Ophthalmol Strabismus. 2017;54:e1-e5.]. Copyright 2017, SLACK Incorporated.

Kinetic Monte Carlo studies of the reaction kinetics of crystal defects that diffuse one-dimensionally with occasional transverse migration

DEFF Research Database (Denmark)

Heinisch, H.L.; Trinkaus, H.; Singh, Bachu Narain

2007-01-01

The reaction kinetics of the various species of mobile defects in irradiated materials are crucially dependent on the dimensionality of their migration. Sink strengths for one-dimensionally (1D) gliding interstitial loops undergoing occasional direction changes have been described analytically...

One-dimensional hypersonic phononic crystals.

Science.gov (United States)

Gomopoulos, N; Maschke, D; Koh, C Y; Thomas, E L; Tremel, W; Butt, H-J; Fytas, G

2010-03-10

We report experimental observation of a normal incidence phononic band gap in one-dimensional periodic (SiO(2)/poly(methyl methacrylate)) multilayer film at gigahertz frequencies using Brillouin spectroscopy. The band gap to midgap ratio of 0.30 occurs for elastic wave propagation along the periodicity direction, whereas for inplane propagation the system displays an effective medium behavior. The phononic properties are well captured by numerical simulations. The porosity in the silica layers presents a structural scaffold for the introduction of secondary active media for potential coupling between phonons and other excitations, such as photons and electrons.

Three-dimensional cooling of muons

CERN Document Server

Vsevolozhskaya, T A

2000-01-01

The simultaneous ionization cooling of muon beams in all three - the longitudinal and two transverse - directions is considered in a scheme, based on bent lithium lenses with dipole constituent of magnetic field in them, created by a special configuration of current-carrying rod. An analysis of three-dimensional cooling is performed with the use of kinetic equation method. Results of numerical calculation for a specific beam line configuration are presented together with results of computer simulation using the Moliere distribution to describe the Coulomb scattering and the Vavilov distribution used to describe the ionization loss of energy.

Dimensional cosmological principles

International Nuclear Information System (INIS)

Chi, L.K.

1985-01-01

The dimensional cosmological principles proposed by Wesson require that the density, pressure, and mass of cosmological models be functions of the dimensionless variables which are themselves combinations of the gravitational constant, the speed of light, and the spacetime coordinates. The space coordinate is not the comoving coordinate. In this paper, the dimensional cosmological principle and the dimensional perfect cosmological principle are reformulated by using the comoving coordinate. The dimensional perfect cosmological principle is further modified to allow the possibility that mass creation may occur. Self-similar spacetimes are found to be models obeying the new dimensional cosmological principle

Three-dimensional density and compressible magnetic structure in solar wind turbulence

Science.gov (United States)

Roberts, Owen W.; Narita, Yasuhito; Escoubet, C.-Philippe

2018-03-01

The three-dimensional structure of both compressible and incompressible components of turbulence is investigated at proton characteristic scales in the solar wind. Measurements of the three-dimensional structure are typically difficult, since the majority of measurements are performed by a single spacecraft. However, the Cluster mission consisting of four spacecraft in a tetrahedral formation allows for a fully three-dimensional investigation of turbulence. Incompressible turbulence is investigated by using the three vector components of the magnetic field. Meanwhile compressible turbulence is investigated by considering the magnitude of the magnetic field as a proxy for the compressible fluctuations and electron density data deduced from spacecraft potential. Application of the multi-point signal resonator technique to intervals of fast and slow wind shows that both compressible and incompressible turbulence are anisotropic with respect to the mean magnetic field direction P⟂ ≫ P∥ and are sensitive to the value of the plasma beta (β; ratio of thermal to magnetic pressure) and the wind type. Moreover, the incompressible fluctuations of the fast and slow solar wind are revealed to be different with enhancements along the background magnetic field direction present in the fast wind intervals. The differences in the fast and slow wind and the implications for the presence of different wave modes in the plasma are discussed.

Generation of structurally novel short carotenoids and study of their biological activity.

Science.gov (United States)

Kim, Se H; Kim, Moon S; Lee, Bun Y; Lee, Pyung C

2016-02-23

Recent research interest in phytochemicals has consistently driven the efforts in the metabolic engineering field toward microbial production of various carotenoids. In spite of systematic studies, the possibility of using C30 carotenoids as biologically functional compounds has not been explored thus far. Here, we generated 13 novel structures of C30 carotenoids and one C35 carotenoid, including acyclic, monocyclic, and bicyclic structures, through directed evolution and combinatorial biosynthesis, in Escherichia coli. Measurement of radical scavenging activity of various C30 carotenoid structures revealed that acyclic C30 carotenoids showed higher radical scavenging activity than did DL-α-tocopherol. We could assume high potential biological activity of the novel structures of C30 carotenoids as well, based on the neuronal differentiation activity observed for the monocyclic C30 carotenoid 4,4'-diapotorulene on rat bone marrow mesenchymal stem cells. Our results demonstrate that a series of structurally novel carotenoids possessing biologically beneficial properties can be synthesized in E. coli.

Separation of time scales in one-dimensional directed nucleation-growth processes

Science.gov (United States)

Pierobon, Paolo; Miné-Hattab, Judith; Cappello, Giovanni; Viovy, Jean-Louis; Lagomarsino, Marco Cosentino

2010-12-01

Proteins involved in homologous recombination such as RecA and hRad51 polymerize on single- and double-stranded DNA according to a nucleation-growth kinetics, which can be monitored by single-molecule in vitro assays. The basic models currently used to extract biochemical rates rely on ensemble averages and are typically based on an underlying process of bidirectional polymerization, in contrast with the often observed anisotropic polymerization of similar proteins. For these reasons, if one considers single-molecule experiments, the available models are useful to understand observations only in some regimes. In particular, recent experiments have highlighted a steplike polymerization kinetics. The classical model of one-dimensional nucleation growth, the Kolmogorov-Avrami-Mehl-Johnson (KAMJ) model, predicts the correct polymerization kinetics only in some regimes and fails to predict the steplike behavior. This work illustrates by simulations and analytical arguments the limitation of applicability of the KAMJ description and proposes a minimal model for the statistics of the steps based on the so-called stick-breaking stochastic process. We argue that this insight might be useful to extract information on the time and length scales involved in the polymerization kinetics.

A parallel algorithm for solving linear equations arising from one-dimensional network problems

International Nuclear Information System (INIS)

Mesina, G.L.

1991-01-01

One-dimensional (1-D) network problems, such as those arising from 1- D fluid simulations and electrical circuitry, produce systems of sparse linear equations which are nearly tridiagonal and contain a few non-zero entries outside the tridiagonal. Most direct solution techniques for such problems either do not take advantage of the special structure of the matrix or do not fully utilize parallel computer architectures. We describe a new parallel direct linear equation solution algorithm, called TRBR, which is especially designed to take advantage of this structure on MIMD shared memory machines. The new method belongs to a family of methods which split the coefficient matrix into the sum of a tridiagonal matrix T and a matrix comprised of the remaining coefficients R. Efficient tridiagonal methods are used to algebraically simplify the linear system. A smaller auxiliary subsystem is created and solved and its solution is used to calculate the solution of the original system. The newly devised BR method solves the subsystem. The serial and parallel operation counts are given for the new method and related earlier methods. TRBR is shown to have the smallest operation count in this class of direct methods. Numerical results are given. Although the algorithm is designed for one-dimensional networks, it has been applied successfully to three-dimensional problems as well. 20 refs., 2 figs., 4 tabs

Face recognition based on two-dimensional discriminant sparse preserving projection

Science.gov (United States)

Zhang, Dawei; Zhu, Shanan

2018-04-01

In this paper, a supervised dimensionality reduction algorithm named two-dimensional discriminant sparse preserving projection (2DDSPP) is proposed for face recognition. In order to accurately model manifold structure of data, 2DDSPP constructs within-class affinity graph and between-class affinity graph by the constrained least squares (LS) and l1 norm minimization problem, respectively. Based on directly operating on image matrix, 2DDSPP integrates graph embedding (GE) with Fisher criterion. The obtained projection subspace preserves within-class neighborhood geometry structure of samples, while keeping away samples from different classes. The experimental results on the PIE and AR face databases show that 2DDSPP can achieve better recognition performance.

Kinetics of two-dimensional electron plasma, interacting with fluctuating potential

International Nuclear Information System (INIS)

Boiko, I.I.; Sirenko, Y.M.

1990-01-01

In this paper, from the first principles, after the fashion of Klimontovich, the authors derive quantum kinetic equation for electron gas, inhomogeneous in z-direction and homogeneous in XY-plane. Special attention is given to the systems with quasi-two-dimensional electron gas (2 DEG), which are widely explored now. Both interaction between the particles of 2 DEG (in general, of several sorts), and interaction with an external system (phonons, impurities, after change carries etc.) are considered. General theory is used to obtain energy and momentum balance equations and relaxation frequencies for 2 DEG in the basis of plane waves. The case of crossed electric and magnetic fields is also treated. As an illustration the problems of 2 DEG scattering on semibounded three-dimensional electron gas and on two-dimensional hole gas are considered; transverse conductivity of nondegenerate 2 DEG, scattered by impurities in ultraquantum magnetic field, is calculated

Direct 3-D morphological measurements of silicone rubber impression using micro-focus X-ray CT.

Science.gov (United States)

Kamegawa, Masayuki; Nakamura, Masayuki; Fukui, Yu; Tsutsumi, Sadami; Hojo, Masaki

2010-01-01

Three-dimensional computer models of dental arches play a significant role in prosthetic dentistry. The microfocus X-ray CT scanner has the advantage of capturing precise 3D shapes of deep fossa, and we propose a new method of measuring the three-dimensional morphology of a dental impression directly, which will eliminate the conversion process to dental casts. Measurement precision and accuracy were evaluated using a standard gage comprised of steel balls which simulate the dental arch. Measurement accuracy, standard deviation of distance distribution of superimposed models, was determined as +/-0.050 mm in comparison with a CAD model. Impressions and casts of an actual dental arch were scanned by microfocus X-ray CT and three-dimensional models were compared. The impression model had finer morphology, especially around the cervical margins of teeth. Within the limitations of the current study, direct three-dimensional impression modeling was successfully demonstrated using microfocus X-ray CT.

Three dimensional reconstruction of computed tomographic images by computer graphics method

International Nuclear Information System (INIS)

Kashiwagi, Toru; Kimura, Kazufumi.

1986-01-01

A three dimensional computer reconstruction system for CT images has been developed in a commonly used radionuclide data processing system using a computer graphics technique. The three dimensional model was constructed from organ surface information of CT images (slice thickness: 5 or 10 mm). Surface contours of the organs were extracted manually from a set of parallel transverse CT slices in serial order and stored in the computer memory. Interpolation was made between a set of the extracted contours by cubic spline functions, then three dimensional models were reconstructed. The three dimensional images were displayed as a wire-frame and/or solid models on the color CRT. Solid model images were obtained as follows. The organ surface constructed from contours was divided into many triangular patches. The intensity of light to each patch was calculated from the direction of incident light, eye position and the normal to the triangular patch. Firstly, this system was applied to the liver phantom. Reconstructed images of the liver phantom were coincident with the actual object. This system also has been applied to human various organs such as brain, lung, liver, etc. The anatomical organ surface was realistically viewed from any direction. The images made us more easily understand the location and configuration of organs in vivo than original CT images. Furthermore, spacial relationship among organs and/or lesions was clearly obtained by superimposition of wire-frame and/or different colored solid models. Therefore, it is expected that this system is clinically useful for evaluating the patho-morphological changes in broad perspective. (author)

The three-dimensional genome organization of Drosophila melanogaster through data integration.

Science.gov (United States)

Li, Qingjiao; Tjong, Harianto; Li, Xiao; Gong, Ke; Zhou, Xianghong Jasmine; Chiolo, Irene; Alber, Frank

2017-07-31

Genome structures are dynamic and non-randomly organized in the nucleus of higher eukaryotes. To maximize the accuracy and coverage of three-dimensional genome structural models, it is important to integrate all available sources of experimental information about a genome's organization. It remains a major challenge to integrate such data from various complementary experimental methods. Here, we present an approach for data integration to determine a population of complete three-dimensional genome structures that are statistically consistent with data from both genome-wide chromosome conformation capture (Hi-C) and lamina-DamID experiments. Our structures resolve the genome at the resolution of topological domains, and reproduce simultaneously both sets of experimental data. Importantly, this data deconvolution framework allows for structural heterogeneity between cells, and hence accounts for the expected plasticity of genome structures. As a case study we choose Drosophila melanogaster embryonic cells, for which both data types are available. Our three-dimensional genome structures have strong predictive power for structural features not directly visible in the initial data sets, and reproduce experimental hallmarks of the D. melanogaster genome organization from independent and our own imaging experiments. Also they reveal a number of new insights about genome organization and its functional relevance, including the preferred locations of heterochromatic satellites of different chromosomes, and observations about homologous pairing that cannot be directly observed in the original Hi-C or lamina-DamID data. Our approach allows systematic integration of Hi-C and lamina-DamID data for complete three-dimensional genome structure calculation, while also explicitly considering genome structural variability.

Water-Induced Dimensionality Reduction in Metal-Halide Perovskites

KAUST Repository

Turedi, Bekir

2018-03-30

Metal-halide perovskite materials are highly attractive materials for optoelectronic applications. However, the instability of perovskite materials caused by moisture and heat-induced degradation impairs future prospects of using these materials. Here we employ water to directly transform films of the three-dimensional (3D) perovskite CsPbBr3 to stable two-dimensional (2D) perovskite-related CsPb2Br5. A sequential dissolution-recrystallization process governs this water induced transformation under PbBr2 rich condition. We find that these post-synthesized 2D perovskite-related material films exhibit excellent stability against humidity and high photoluminescence quantum yield. We believe that our results provide a new synthetic method to generate stable 2D perovskite-related materials that could be applicable for light emitting device applications.

New apparatus for direct counting of β particles from two-dimensional gels and an application to changes in protein synthesis due to cell density

International Nuclear Information System (INIS)

Anderson, H.L.; Puck, T.T.; Shera, E.B.

1987-07-01

A new method is described for scanning two-dimensional gels by the direct counting of β particles instead of autoradiography. The methodology is described; results are compared with autoradiographic results; and data are presented demonstrating changed patterns of protein synthesis accompanying changes in cell density. The method is rapid and permits identification of differences in protein abundance of approximately 10% for a substantial fraction of the more prominent proteins. A modulation effect of more than 5 standard deviations, accompanying contact inhibition of cell growth, is shown to occur for an appreciable number of these proteins. The method promises to be applicable to a variety of biochemical and genetic experiments designed to delineate changes in protein synthesis accompanying changes in genome, molecular environment, history, and state of differentiation of the cell populations studied. 13 refs., 8 figs., 4 tabs

Dimensional comparison theory.

Science.gov (United States)

Möller, Jens; Marsh, Herb W

2013-07-01

Although social comparison (Festinger, 1954) and temporal comparison (Albert, 1977) theories are well established, dimensional comparison is a largely neglected yet influential process in self-evaluation. Dimensional comparison entails a single individual comparing his or her ability in a (target) domain with his or her ability in a standard domain (e.g., "How good am I in math compared with English?"). This article reviews empirical findings from introspective, path-analytic, and experimental studies on dimensional comparisons, categorized into 3 groups according to whether they address the "why," "with what," or "with what effect" question. As the corresponding research shows, dimensional comparisons are made in everyday life situations. They impact on domain-specific self-evaluations of abilities in both domains: Dimensional comparisons reduce self-concept in the worse off domain and increase self-concept in the better off domain. The motivational basis for dimensional comparisons, their integration with recent social cognitive approaches, and the interdependence of dimensional, temporal, and social comparisons are discussed. PsycINFO Database Record (c) 2013 APA, all rights reserved.

The 'thousand words' problem: Summarizing multi-dimensional data

International Nuclear Information System (INIS)

Scott, David M.

2011-01-01

Research highlights: → Sophisticated process sensors produce large multi-dimensional data sets. → Plant control systems cannot handle images or large amounts of data. → Various techniques reduce the dimensionality, extracting information from raw data. → Simple 1D and 2D methods can often be extended to 3D and 4D applications. - Abstract: An inherent difficulty in the application of multi-dimensional sensing to process monitoring and control is the extraction and interpretation of useful information. Ultimately the measured data must be collapsed into a relatively small number of values that capture the salient characteristics of the process. Although multiple dimensions are frequently necessary to isolate a particular physical attribute (such as the distribution of a particular chemical species in a reactor), plant control systems are not equipped to use such data directly. The production of a multi-dimensional data set (often displayed as an image) is not the final step of the measurement process, because information must still be extracted from the raw data. In the metaphor of one picture being equal to a thousand words, the problem becomes one of paraphrasing a lengthy description of the image with one or two well-chosen words. Various approaches to solving this problem are discussed using examples from the fields of particle characterization, image processing, and process tomography.

Knitting Technologies And Tensile Properties Of A Novel Curved Flat-Knitted Three-Dimensional Spacer Fabrics

Directory of Open Access Journals (Sweden)

Li Xiaoying

2015-09-01

Full Text Available This paper introduces a knitting technique for making innovative curved three-dimensional (3D spacer fabrics by the computer flat-knitting machine. During manufacturing, a number of reinforcement yarns made of aramid fibres are inserted into 3D spacer fabrics along the weft direction to enhance the fabric tensile properties. Curved, flat-knitted 3D spacer fabrics with different angles (in the warp direction were also developed. Tensile tests were carried out in the weft and warp directions for the two spacer fabrics (with and without reinforcement yarns, and their stress–strain curves were compared. The results showed that the reinforcement yarns can reduce the fabric deformation and improve tensile stress and dimensional stability of 3D spacer fabrics. This research can help the further study of 3D spacer fabric when applied to composites.

Three-dimensional immobilization of beta-galactosidase on a silicon surface.

Science.gov (United States)

Betancor, Lorena; Luckarift, Heather R; Seo, Jae H; Brand, Oliver; Spain, Jim C

2008-02-01

Many alternative strategies to immobilize and stabilize enzymes have been investigated in recent years for applications in biosensors. The entrapment of enzymes within silica-based nanospheres formed through silicification reactions provides high loading capacities for enzyme immobilization, resulting in high volumetric activity and enhanced mechanical stability. Here we report a strategy for chemically associating silica nanospheres containing entrapped enzyme to a silicon support. beta-galactosidase from E. coli was used as a model enzyme due to its versatility as a biosensor for lactose. The immobilization strategy resulted in a three-dimensional network of silica attached directly at the silicon surface, providing a significant increase in surface area and a corresponding 3.5-fold increase in enzyme loading compared to enzyme attached directly at the surface. The maximum activity recovered for a silicon square sample of 0.5 x 0.5 cm was 0.045 IU using the direct attachment of the enzyme through glutaraldehyde and 0.16 IU when using silica nanospheres. The immobilized beta-galactosidase prepared by silica deposition was stable and retained more than 80% of its initial activity after 10 days at 24 degrees C. The ability to generate three-dimensional structures with enhanced loading capacity for biosensing molecules offers the potential to substantially amplify biosensor sensitivity. (c) 2007 Wiley Periodicals, Inc.

Chern-Simons action for inhomogeneous Virasoro group as extension of three dimensional flat gravity

Energy Technology Data Exchange (ETDEWEB)

Barnich, Glenn [Physique Théorique et Mathématique, Université Libre de Bruxelles and International Solvay Institutes, Campus Plaine C.P. 231, B-1050 Bruxelles (Belgium); Giribet, Gastón [Physique Théorique et Mathématique, Université Libre de Bruxelles and International Solvay Institutes, Campus Plaine C.P. 231, B-1050 Bruxelles (Belgium); Universidad de Buenos Aires FCEN-UBA and IFIBA-CONICET, Ciudad Universitaria, Pabellón I, 1428 Buenos Aires (Argentina); Instituto de Física, Pontificia Universidad Católica de Valparaíso, Casilla 4059, Valparaíso (Chile); Leston, Mauricio [Instituto de Astronomía y Física del Espacio IAFE-CONICET, Ciudad Universitaria, Pabellón IAFE, C.C. 67 Suc. 28, 1428 Buenos Aires (Argentina)

2015-07-15

We initiate the study of a Chern-Simons action associated to the semi-direct sum of the Virasoro algebra with its coadjoint representation. This model extends the standard Chern-Simons formulation of three dimensional flat gravity and is similar to the higher-spin extension of three dimensional anti-de Sitter or flat gravity. The extension can also be constructed for the exotic but not for the cosmological constant deformation of flat gravity.

Three-Dimensional Target Localization and Cramér-Rao Bound for Two-Dimensional OFDM-MIMO Radar

Directory of Open Access Journals (Sweden)

Xingxing Li

2017-01-01

Full Text Available Target localization using a frequency diversity multiple-input multiple-output (MIMO system is one of the hottest research directions in the radar society. In this paper, three-dimensional (3D target localization is considered for two-dimensional MIMO radar with orthogonal frequency division multiplexing linear frequency modulated (OFDM-LFM waveforms. To realize joint estimation for range and angle in azimuth and elevation, the range-angle-dependent beam pattern with high range resolution is produced by the OFDM-LFM waveform. Then, the 3D target localization proposal is presented and the corresponding closed-form expressions of Cramér-Rao bound (CRB are derived. Furthermore, for mitigating the coupling of angle and range and further improving the estimation precision, a CRB optimization method is proposed. Different from the existing methods of FDA-based radar, the proposed method can provide higher range estimation because of multiple transmitted frequency bands. Numerical simulation results are provided to demonstrate the effectiveness of the proposed approach and its improved performance of target localization.

Direct Simulation Monte Carlo Application of the Three Dimensional Forced Harmonic Oscillator Model

Science.gov (United States)

2017-12-07

NUMBER (Include area code) 07 December 2017 Journal Article 24 February 2017 - 31 December 2017 Direct Simulation Monte Carlo Application of the...is proposed. The implementation employs precalculated lookup tables for transition probabilities and is suitable for the direct simulation Monte Carlo...method. It takes into account the microscopic reversibility between the excitation and deexcitation processes , and it satisfies the detailed balance

The dimension split element-free Galerkin method for three-dimensional potential problems

Science.gov (United States)

Meng, Z. J.; Cheng, H.; Ma, L. D.; Cheng, Y. M.

2018-02-01

This paper presents the dimension split element-free Galerkin (DSEFG) method for three-dimensional potential problems, and the corresponding formulae are obtained. The main idea of the DSEFG method is that a three-dimensional potential problem can be transformed into a series of two-dimensional problems. For these two-dimensional problems, the improved moving least-squares (IMLS) approximation is applied to construct the shape function, which uses an orthogonal function system with a weight function as the basis functions. The Galerkin weak form is applied to obtain a discretized system equation, and the penalty method is employed to impose the essential boundary condition. The finite difference method is selected in the splitting direction. For the purposes of demonstration, some selected numerical examples are solved using the DSEFG method. The convergence study and error analysis of the DSEFG method are presented. The numerical examples show that the DSEFG method has greater computational precision and computational efficiency than the IEFG method.

Quantum phase space points for Wigner functions in finite-dimensional spaces

OpenAIRE

Luis Aina, Alfredo

2004-01-01

We introduce quantum states associated with single phase space points in the Wigner formalism for finite-dimensional spaces. We consider both continuous and discrete Wigner functions. This analysis provides a procedure for a direct practical observation of the Wigner functions for states and transformations without inversion formulas.

Quantum phase space points for Wigner functions in finite-dimensional spaces

International Nuclear Information System (INIS)

Luis, Alfredo

2004-01-01

We introduce quantum states associated with single phase space points in the Wigner formalism for finite-dimensional spaces. We consider both continuous and discrete Wigner functions. This analysis provides a procedure for a direct practical observation of the Wigner functions for states and transformations without inversion formulas

Inversion of reflection for the one-dimensional Dirac equation

International Nuclear Information System (INIS)

Clerk, G.L.; Davies, A.J.

1991-01-01

It is a general result of one-dimensional non-relativistic quantum mechanics that the coefficient of reflection (reflected flux) is the same irrespective of the direction of traversing a potential barrier, a result that is independent of the barrier shape. In this note, the authors consider the transmission coefficient instead, and derive a strong result, namely that the transmission amplitude is independent of the direction of barrier traversal. That is, the transmission amplitude has the same complex phase as well as being unchanged in magnitude by changing the barrier around. This process was called inversion of reflection. 2 refs

Correlation Functions of the One-Dimensional Attractive Bose Gas

International Nuclear Information System (INIS)

Calabrese, Pasquale; Caux, Jean-Sebastien

2007-01-01

The zero-temperature correlation functions of the one-dimensional attractive Bose gas with a delta-function interaction are calculated analytically for any value of the interaction parameter and number of particles, directly from the integrability of the model. We point out a number of interesting features, including zero recoil energy for a large number of particles, analogous to the Moessbauer effect

Nonlinear dimensionality reduction methods for synthetic biology biobricks' visualization.

Science.gov (United States)

Yang, Jiaoyun; Wang, Haipeng; Ding, Huitong; An, Ning; Alterovitz, Gil

2017-01-19

Visualizing data by dimensionality reduction is an important strategy in Bioinformatics, which could help to discover hidden data properties and detect data quality issues, e.g. data noise, inappropriately labeled data, etc. As crowdsourcing-based synthetic biology databases face similar data quality issues, we propose to visualize biobricks to tackle them. However, existing dimensionality reduction methods could not be directly applied on biobricks datasets. Hereby, we use normalized edit distance to enhance dimensionality reduction methods, including Isomap and Laplacian Eigenmaps. By extracting biobricks from synthetic biology database Registry of Standard Biological Parts, six combinations of various types of biobricks are tested. The visualization graphs illustrate discriminated biobricks and inappropriately labeled biobricks. Clustering algorithm K-means is adopted to quantify the reduction results. The average clustering accuracy for Isomap and Laplacian Eigenmaps are 0.857 and 0.844, respectively. Besides, Laplacian Eigenmaps is 5 times faster than Isomap, and its visualization graph is more concentrated to discriminate biobricks. By combining normalized edit distance with Isomap and Laplacian Eigenmaps, synthetic biology biobircks are successfully visualized in two dimensional space. Various types of biobricks could be discriminated and inappropriately labeled biobricks could be determined, which could help to assess crowdsourcing-based synthetic biology databases' quality, and make biobricks selection.

Classifying and assembling two-dimensional X-ray laser diffraction patterns of a single particle to reconstruct the three-dimensional diffraction intensity function: resolution limit due to the quantum noise.

Science.gov (United States)

Tokuhisa, Atsushi; Taka, Junichiro; Kono, Hidetoshi; Go, Nobuhiro

2012-05-01

A new two-step algorithm is developed for reconstructing the three-dimensional diffraction intensity of a globular biological macromolecule from many experimentally measured quantum-noise-limited two-dimensional X-ray laser diffraction patterns, each for an unknown orientation. The first step is classification of the two-dimensional patterns into groups according to the similarity of direction of the incident X-rays with respect to the molecule and an averaging within each group to reduce the noise. The second step is detection of common intersecting circles between the signal-enhanced two-dimensional patterns to identify their mutual location in the three-dimensional wavenumber space. The newly developed algorithm enables one to detect a signal for classification in noisy experimental photon-count data with as low as ~0.1 photons per effective pixel. The wavenumber of such a limiting pixel determines the attainable structural resolution. From this fact, the resolution limit due to the quantum noise attainable by this new method of analysis as well as two important experimental parameters, the number of two-dimensional patterns to be measured (the load for the detector) and the number of pairs of two-dimensional patterns to be analysed (the load for the computer), are derived as a function of the incident X-ray intensity and quantities characterizing the target molecule. © 2012 International Union of Crystallography

Strain-engineered growth of two-dimensional materials.

Science.gov (United States)

Ahn, Geun Ho; Amani, Matin; Rasool, Haider; Lien, Der-Hsien; Mastandrea, James P; Ager Iii, Joel W; Dubey, Madan; Chrzan, Daryl C; Minor, Andrew M; Javey, Ali

2017-09-20

The application of strain to semiconductors allows for controlled modification of their band structure. This principle is employed for the manufacturing of devices ranging from high-performance transistors to solid-state lasers. Traditionally, strain is typically achieved via growth on lattice-mismatched substrates. For two-dimensional (2D) semiconductors, this is not feasible as they typically do not interact epitaxially with the substrate. Here, we demonstrate controlled strain engineering of 2D semiconductors during synthesis by utilizing the thermal coefficient of expansion mismatch between the substrate and semiconductor. Using WSe 2 as a model system, we demonstrate stable built-in strains ranging from 1% tensile to 0.2% compressive on substrates with different thermal coefficient of expansion. Consequently, we observe a dramatic modulation of the band structure, manifested by a strain-driven indirect-to-direct bandgap transition and brightening of the dark exciton in bilayer and monolayer WSe 2 , respectively. The growth method developed here should enable flexibility in design of more sophisticated devices based on 2D materials.Strain engineering is an essential tool for modifying local electronic properties in silicon-based electronics. Here, Ahn et al. demonstrate control of biaxial strain in two-dimensional materials based on the growth substrate, enabling more complex low-dimensional electronics.

Direct, enantioselective α-alkylation of aldehydes using simple olefins.

Science.gov (United States)

Capacci, Andrew G; Malinowski, Justin T; McAlpine, Neil J; Kuhne, Jerome; MacMillan, David W C

2017-11-01

Although the α-alkylation of ketones has already been established, the analogous reaction using aldehyde substrates has proven surprisingly elusive. Despite the structural similarities between the two classes of compounds, the sensitivity and unique reactivity of the aldehyde functionality has typically required activated substrates or specialized additives. Here, we show that the synergistic merger of three catalytic processes-photoredox, enamine and hydrogen-atom transfer (HAT) catalysis-enables an enantioselective α-aldehyde alkylation reaction that employs simple olefins as coupling partners. Chiral imidazolidinones or prolinols, in combination with a thiophenol, iridium photoredox catalyst and visible light, have been successfully used in a triple catalytic process that is temporally sequenced to deliver a new hydrogen and electron-borrowing mechanism. This multicatalytic process enables both intra- and intermolecular aldehyde α-methylene coupling with olefins to construct both cyclic and acyclic products, respectively. With respect to atom and step-economy ideals, this stereoselective process allows the production of high-value molecules from feedstock chemicals in one step while consuming only photons.

Method of solving conformal models in D-dimensional space I

International Nuclear Information System (INIS)

Fradkin, E.S.; Palchik, M.Y.

1996-01-01

We study the Hilbert space of conformal field theory in D-dimensional space. The latter is shown to have model-independent structure. The states of matter fields and gauge fields form orthogonal subspaces. The dynamical principle fixing the choice of model may be formulated either in each of these subspaces or in their direct sum. In the latter case, gauge interactions are necessarily present in the model. We formulate the conditions specifying the class of models where gauge interactions are being neglected. The anomalous Ward identities are derived. Different values of anomalous parameters (D-dimensional analogs of a central charge, including operator ones) correspond to different models. The structure of these models is analogous to that of 2-dimensional conformal theories. Each model is specified by D-dimensional analog of null vector. The exact solutions of the simplest models of this type are examined. It is shown that these models are equivalent to Lagrangian models of scalar fields with a triple interaction. The values of dimensions of such fields are calculated, and the closed sets of differential equations for higher Green functions are derived. Copyright copyright 1996 Academic Press, Inc

Pattern formation and three-dimensional instability in rotating flows

Science.gov (United States)

Christensen, Erik A.; Aubry, Nadine; Sorensen, Jens N.

1997-03-01

A fluid flow enclosed in a cylindrical container where fluid motion is created by the rotation of one end wall as a centrifugal fan is studied. Direct numerical simulations and spatio-temporal analysis have been performed in the early transition scenario, which includes a steady-unsteady transition and a breakdown of axisymmetric to three-dimensional flow behavior. In the early unsteady regime of the flow, the central vortex undergoes a vertical beating motion, accompanied by axisymmetric spikes formation on the edge of the breakdown bubble. As traveling waves, the spikes move along the central vortex core toward the rotating end-wall. As the Reynolds number is increased further, the flow undergoes a three-dimensional instability. The influence of the latter on the previous patterns is studied.

Direct Conversion of Equine Adipose-Derived Stem Cells into Induced Neuronal Cells Is Enhanced in Three-Dimensional Culture.

Science.gov (United States)

Petersen, Gayle F; Hilbert, Bryan J; Trope, Gareth D; Kalle, Wouter H J; Strappe, Padraig M

2015-12-01

The ability to culture neurons from horses may allow further investigation into equine neurological disorders. In this study, we demonstrate the generation of induced neuronal cells from equine adipose-derived stem cells (EADSCs) using a combination of lentiviral vector expression of the neuronal transcription factors Brn2, Ascl1, Myt1l (BAM) and NeuroD1 and a defined chemical induction medium, with βIII-tubulin-positive induced neuronal cells displaying a distinct neuronal morphology of rounded and compact cell bodies, extensive neurite outgrowth, and branching of processes. Furthermore, we investigated the effects of dimensionality on neuronal transdifferentiation, comparing conventional two-dimensional (2D) monolayer culture against three-dimensional (3D) culture on a porous polystyrene scaffold. Neuronal transdifferentiation was enhanced in 3D culture, with evenly distributed cells located on the surface and throughout the scaffold. Transdifferentiation efficiency was increased in 3D culture, with an increase in mean percent conversion of more than 100% compared to 2D culture. Additionally, induced neuronal cells were shown to transit through a Nestin-positive precursor state, with MAP2 and Synapsin 2 expression significantly increased in 3D culture. These findings will help to increase our understanding of equine neuropathogenesis, with prospective roles in disease modeling, drug screening, and cellular replacement for treatment of equine neurological disorders.

First principles calculation of two dimensional antimony and antimony arsenide

Energy Technology Data Exchange (ETDEWEB)

Pillai, Sharad Babu, E-mail: sbpillai001@gmail.com; Narayan, Som; Jha, Prafulla K. [Department. of Physics, Faculty of Science, The M. S. University of Baroda, Vadodara-390002 (India); Dabhi, Shweta D. [Department of Physics, Maharaja Krishnakumarsinhji Bhavnagar University, Bhavnagar-364001 (India)

2016-05-23

This work focuses on the strain dependence of the electronic properties of two dimensional antimony (Sb) material and its alloy with As (SbAs) using density functional theory based first principles calculations. Both systems show indirect bandgap semiconducting character which can be transformed into a direct bandgap material with the application of relatively small strain.

Three-Dimensional Inverse Transport Solver Based on Compressive Sensing Technique

Science.gov (United States)

Cheng, Yuxiong; Wu, Hongchun; Cao, Liangzhi; Zheng, Youqi

2013-09-01

According to the direct exposure measurements from flash radiographic image, a compressive sensing-based method for three-dimensional inverse transport problem is presented. The linear absorption coefficients and interface locations of objects are reconstructed directly at the same time. It is always very expensive to obtain enough measurements. With limited measurements, compressive sensing sparse reconstruction technique orthogonal matching pursuit is applied to obtain the sparse coefficients by solving an optimization problem. A three-dimensional inverse transport solver is developed based on a compressive sensing-based technique. There are three features in this solver: (1) AutoCAD is employed as a geometry preprocessor due to its powerful capacity in graphic. (2) The forward projection matrix rather than Gauss matrix is constructed by the visualization tool generator. (3) Fourier transform and Daubechies wavelet transform are adopted to convert an underdetermined system to a well-posed system in the algorithm. Simulations are performed and numerical results in pseudo-sine absorption problem, two-cube problem and two-cylinder problem when using compressive sensing-based solver agree well with the reference value.

Observation of Zero-Dimensional States in a One-Dimensional Electron Interferometer

NARCIS (Netherlands)

Wees, B.J. van; Kouwenhoven, L.P.; Harmans, C.J.P.M.; Williamson, J.G.; Timmering, C.E.; Broekaart, M.E.I.; Foxon, C.T.; Harris, J.J.

1989-01-01

We have studied the electron transport in a one-dimensional electron interferometer. It consists of a disk-shaped two-dimensional electron gas, to which quantum point contacts are attached. Discrete zero-dimensional states are formed due to constructive interference of electron waves traveling along

Lower dimensional gravity

International Nuclear Information System (INIS)

Brown, J.D.

1988-01-01

This book addresses the subject of gravity theories in two and three spacetime dimensions. The prevailing philosophy is that lower dimensional models of gravity provide a useful arena for developing new ideas and insights, which are applicable to four dimensional gravity. The first chapter consists of a comprehensive introduction to both two and three dimensional gravity, including a discussion of their basic structures. In the second chapter, the asymptotic structure of three dimensional Einstein gravity with a negative cosmological constant is analyzed. The third chapter contains a treatment of the effects of matter sources in classical two dimensional gravity. The fourth chapter gives a complete analysis of particle pair creation by electric and gravitational fields in two dimensions, and the resulting effect on the cosmological constant

Assessment of RELAP5-3D copyright using data from two-dimensional RPI flow tests

International Nuclear Information System (INIS)

Davis, C.B.

1998-01-01

The capability of the RELAP5-3D copyright computer code to perform multi-dimensional thermal-hydraulic analysis was assessed using data from steady-state flow tests conducted at Rensselaer Polytechnic Institute (RPI). The RPI data were taken in a two-dimensional test section in a low-pressure air/water loop. The test section consisted of a thin vertical channel that simulated a two-dimensional slice through the core of a pressurized water reactor. Single-phase and two-phase flows were supplied to the test section in an asymmetric manner to generate a two-dimensional flow field. A traversing gamma densitometer was used to measure void fraction at many locations in the test section. High speed photographs provided information on the flow patterns and flow regimes. The RPI test section was modeled using the multi-dimensional component in RELAP5-3D Version BF06. Calculations of three RPI experiments were performed. The flow regimes predicted by the base code were in poor agreement with those observed in the tests. The two-phase regions were observed to be in the bubbly and slug flow regimes in the test. However, nearly all of the junctions in the horizontal direction were calculated to be in the stratified flow regime because of the relatively low velocities in that direction. As a result, the void fraction predictions were also in poor agreement with the measured values. Significantly improved results were obtained in sensitivity calculations with a modified version of the code that prevented the horizontal junctions from entering the stratified flow regime. These results indicate that the code's logic in the determination of flow regimes in a multi-dimensional component must be improved. The results of the sensitivity calculations also indicate that RELAP5-3D will provide a significant multi-dimensional hydraulic analysis capability once the flow regime prediction is improved

Sub-nanometre channels embedded in two-dimensional materials

KAUST Repository

Han, Yimo

2017-12-04

Two-dimensional (2D) materials are among the most promising candidates for next-generation electronics due to their atomic thinness, allowing for flexible transparent electronics and ultimate length scaling1. Thus far, atomically thin p–n junctions2,3,4,5,6,7,8, metal–semiconductor contacts9,10,11, and metal–insulator barriers12,13,14 have been demonstrated. Although 2D materials achieve the thinnest possible devices, precise nanoscale control over the lateral dimensions is also necessary. Here, we report the direct synthesis of sub-nanometre-wide one-dimensional (1D) MoS2 channels embedded within WSe2 monolayers, using a dislocation-catalysed approach. The 1D channels have edges free of misfit dislocations and dangling bonds, forming a coherent interface with the embedding 2D matrix. Periodic dislocation arrays produce 2D superlattices of coherent MoS2 1D channels in WSe2. Using molecular dynamics simulations, we have identified other combinations of 2D materials where 1D channels can also be formed. The electronic band structure of these 1D channels offers the promise of carrier confinement in a direct-gap material and the charge separation needed to access the ultimate length scales necessary for future electronic applications.

Theory of superfluidity and drag force in the one-dimensional Bose gas

NARCIS (Netherlands)

Cherny, A.Y.; Caux, J.-S.; Brand, J.

2012-01-01

The one-dimensional Bose gas is an unusual superfluid. In contrast to higher spatial dimensions, the existence of non-classical rotational inertia is not directly linked to the dissipationless motion of infinitesimal impurities. Recently, experimental tests with ultracold atoms have begun and

Quantum Secure Direct Intercommunication with Superdense Coding and Entanglement Swapping

International Nuclear Information System (INIS)

Huang Dazu; Guo Ying; Zeng Guihua

2008-01-01

A quantum secure direct intercommunication scheme is proposed to exchange directly the communicators' secret messages by making use of swapping entanglement of Bell states. It has great capacity to distribute the secret messages since these messages have been imposed on high-dimensional Bell states via the local unitary operations with superdense coding. The security is ensured by the secure transmission of the travel sequences and the application of entanglement swapping

Direct and inverse scattering for viscoelastic media

International Nuclear Information System (INIS)

Ammicht, E.; Corones, J.P.; Krueger, R.J.

1987-01-01

A time domain approach to direct and inverse scattering problems for one-dimensional viscoelastic media is presented. Such media can be characterized as having a constitutive relation between stress and strain which involves the past history of the strain through a memory function, the relaxation modulus. In the approach in this article, the relaxation modulus of a material is shown to be related to the reflection properties of the material. This relation provides a constructive algorithm for direct and inverse scattering problems. A numerical implementation of this algorithm is tested on several problems involving realistic relaxation moduli

Maximizing Lumen Gain With Directional Atherectomy.

Science.gov (United States)

Stanley, Gregory A; Winscott, John G

2016-08-01

To describe the use of a low-pressure balloon inflation (LPBI) technique to delineate intraluminal plaque and guide directional atherectomy in order to maximize lumen gain and achieve procedure success. The technique is illustrated in a 77-year-old man with claudication who underwent superficial femoral artery revascularization using a HawkOne directional atherectomy catheter. A standard angioplasty balloon was inflated to 1 to 2 atm during live fluoroscopy to create a 3-dimensional "lumenogram" of the target lesion. Directional atherectomy was performed only where plaque impinged on the balloon at a specific fluoroscopic orientation. The results of the LPBI technique were corroborated with multimodality diagnostic imaging, including digital subtraction angiography, intravascular ultrasound, and intra-arterial pressure measurements. With the LPBI technique, directional atherectomy can routinely achieve <10% residual stenosis, as illustrated in this case, thereby broadly supporting a no-stent approach to lower extremity endovascular revascularization. © The Author(s) 2016.

Transport and hydrodynamic calculations of direct photons at FAIR

International Nuclear Information System (INIS)

Baeuchle, Bjorn; Bleicher, Marcus

2011-01-01

The microscopic transport model UrQMD and a micro + macro hybrid model are used to calculate direct photon spectra from U+U-collisions at E lab =35 A GeV as will be measured by the CBM Collaboration at FAIR. In the hybrid model, the intermediate high-density part of the nuclear interaction is described with ideal 3+1-dimensional hydrodynamics. Different equations of state of the matter created in the heavy-ion collisions are investigated and the resulting spectra of direct photons are predicted. The emission patterns of direct photons in space and time are discussed.

On symmetry reduction and exact solutions of the linear one-dimensional Schroedinger equation

International Nuclear Information System (INIS)

Barannik, L.L.

1996-01-01

Symmetry reduction of the Schroedinger equation with potential is carried out on subalgebras of the Lie algebra which is the direct sum of the special Galilei algebra and one-dimensional algebra. Some new exact solutions are obtained

Direct-write three-dimensional nanofabrication of nanopyramids and nanocones on Si by nanotumefaction using a helium ion microscope

Science.gov (United States)

Zhang, L.; Heinig, N. F.; Bazargan, S.; Abd-Ellah, M.; Moghimi, N.; Leung, K. T.

2015-06-01

The recently commercialized helium ion microscope (HIM) has already demonstrated its outstanding imaging capabilities in terms of resolution, surface sensitivity, depth of field and ease of charge compensation. Here, we show its exceptional patterning capabilities by fabricating dense lines and three-dimensional (3D) nanostructures on a Si substrate. Small focusing spot size and confined ion-Si interaction volume of a high-energy helium ion beam account for the high resolution in HIM patterning. We demonstrate that a set of resolvable parallel lines with a half pitch as small as 3.5 nm can be achieved. During helium ion bombardment of the Si surface, implantation outperforms milling due to the small mass of the helium ions, which produces tumefaction instead of depression in the Si surface. The Si surface tumefaction is the result of different kinetic processes including diffusion, coalescence and nanobubble formation of the implanted ions, and is found to be very stable structurally at room temperature. Under appropriate conditions, a linear dependence of the surface swollen height on the ion doses can be observed. This relation has enabled us to fabricate nanopyramids and nanocones, thus demonstrating that HIM patterning provides a new ‘bottom-up’ approach to fabricate 3D nanostructures. This surface tumefaction method is direct, both positioning and height accurate, and free of resist, etch, mode and precursor, and it promises new applications in nanoimprint mold fabrication and photomask clear defect reparation.

Direct-write three-dimensional nanofabrication of nanopyramids and nanocones on Si by nanotumefaction using a helium ion microscope

International Nuclear Information System (INIS)

Zhang, L; Heinig, N F; Bazargan, S; Abd-Ellah, M; Moghimi, N; Leung, K T

2015-01-01

The recently commercialized helium ion microscope (HIM) has already demonstrated its outstanding imaging capabilities in terms of resolution, surface sensitivity, depth of field and ease of charge compensation. Here, we show its exceptional patterning capabilities by fabricating dense lines and three-dimensional (3D) nanostructures on a Si substrate. Small focusing spot size and confined ion–Si interaction volume of a high-energy helium ion beam account for the high resolution in HIM patterning. We demonstrate that a set of resolvable parallel lines with a half pitch as small as 3.5 nm can be achieved. During helium ion bombardment of the Si surface, implantation outperforms milling due to the small mass of the helium ions, which produces tumefaction instead of depression in the Si surface. The Si surface tumefaction is the result of different kinetic processes including diffusion, coalescence and nanobubble formation of the implanted ions, and is found to be very stable structurally at room temperature. Under appropriate conditions, a linear dependence of the surface swollen height on the ion doses can be observed. This relation has enabled us to fabricate nanopyramids and nanocones, thus demonstrating that HIM patterning provides a new ‘bottom-up’ approach to fabricate 3D nanostructures. This surface tumefaction method is direct, both positioning and height accurate, and free of resist, etch, mode and precursor, and it promises new applications in nanoimprint mold fabrication and photomask clear defect reparation. (paper)

A novel fusion method of improved adaptive LTP and two-directional two-dimensional PCA for face feature extraction

Science.gov (United States)

Luo, Yuan; Wang, Bo-yu; Zhang, Yi; Zhao, Li-ming

2018-03-01

In this paper, under different illuminations and random noises, focusing on the local texture feature's defects of a face image that cannot be completely described because the threshold of local ternary pattern (LTP) cannot be calculated adaptively, a local three-value model of improved adaptive local ternary pattern (IALTP) is proposed. Firstly, the difference function between the center pixel and the neighborhood pixel weight is established to obtain the statistical characteristics of the central pixel and the neighborhood pixel. Secondly, the adaptively gradient descent iterative function is established to calculate the difference coefficient which is defined to be the threshold of the IALTP operator. Finally, the mean and standard deviation of the pixel weight of the local region are used as the coding mode of IALTP. In order to reflect the overall properties of the face and reduce the dimension of features, the two-directional two-dimensional PCA ((2D)2PCA) is adopted. The IALTP is used to extract local texture features of eyes and mouth area. After combining the global features and local features, the fusion features (IALTP+) are obtained. The experimental results on the Extended Yale B and AR standard face databases indicate that under different illuminations and random noises, the algorithm proposed in this paper is more robust than others, and the feature's dimension is smaller. The shortest running time reaches 0.329 6 s, and the highest recognition rate reaches 97.39%.

High-resolution two-dimensional and three-dimensional modeling of wire grid polarizers and micropolarizer arrays

Science.gov (United States)

Vorobiev, Dmitry; Ninkov, Zoran

2017-11-01

Recent advances in photolithography allowed the fabrication of high-quality wire grid polarizers for the visible and near-infrared regimes. In turn, micropolarizer arrays (MPAs) based on wire grid polarizers have been developed and used to construct compact, versatile imaging polarimeters. However, the contrast and throughput of these polarimeters are significantly worse than one might expect based on the performance of large area wire grid polarizers or MPAs, alone. We investigate the parameters that affect the performance of wire grid polarizers and MPAs, using high-resolution two-dimensional and three-dimensional (3-D) finite-difference time-domain simulations. We pay special attention to numerical errors and other challenges that arise in models of these and other subwavelength optical devices. Our tests show that simulations of these structures in the visible and near-IR begin to converge numerically when the mesh size is smaller than ˜4 nm. The performance of wire grid polarizers is very sensitive to the shape, spacing, and conductivity of the metal wires. Using 3-D simulations of micropolarizer "superpixels," we directly study the cross talk due to diffraction at the edges of each micropolarizer, which decreases the contrast of MPAs to ˜200∶1.

Multifractal and higher-dimensional zeta functions

International Nuclear Information System (INIS)

Véhel, Jacques Lévy; Mendivil, Franklin

2011-01-01

In this paper, we generalize the zeta function for a fractal string (as in Lapidus and Frankenhuijsen 2006 Fractal Geometry, Complex Dimensions and Zeta Functions: Geometry and Spectra of Fractal Strings (New York: Springer)) in several directions. We first modify the zeta function to be associated with a sequence of covers instead of the usual definition involving gap lengths. This modified zeta function allows us to define both a multifractal zeta function and a zeta function for higher-dimensional fractal sets. In the multifractal case, the critical exponents of the zeta function ζ(q, s) yield the usual multifractal spectrum of the measure. The presence of complex poles for ζ(q, s) indicates oscillations in the continuous partition function of the measure, and thus gives more refined information about the multifractal spectrum of a measure. In the case of a self-similar set in R n , the modified zeta function yields asymptotic information about both the 'box' counting function of the set and the n-dimensional volume of the ε-dilation of the set

A zero-dimensional EXTRAP computer code

International Nuclear Information System (INIS)

Karlsson, P.

1982-10-01

A zero-dimensional computer code has been designed for the EXTRAP experiment to predict the density and the temperature and their dependence upon paramenters such as the plasma current and the filling pressure of neutral gas. EXTRAP is a Z-pinch immersed in a vacuum octupole field and could be either linear or toroidal. In this code the density and temperature are assumed to be constant from the axis up to a breaking point from where they decrease linearly in the radial direction out to the plasma radius. All quantities, however, are averaged over the plasma volume thus giving the zero-dimensional character of the code. The particle, momentum and energy one-fluid equations are solved including the effects of the surrounding neutral gas and oxygen impurities. The code shows that the temperature and density are very sensitive to the shape of the plasma, flatter profiles giving higher temperatures and densities. The temperature, however, is not strongly affected for oxygen concentration less than 2% and is well above the radiation barrier even for higher concentrations. (Author)

Estimation of center line and diameter of brain blood vessel using three-dimensional blood vessel matching method with head three-dimensional CTA image

International Nuclear Information System (INIS)

Maekawa, Masashi; Shinohara, Toshihiro; Nakayama, Masato; Nakasako, Noboru

2010-01-01

To support and automate the brain blood vessel disease diagnosis, a novel method to obtain the center line and the diameter of a blood vessel is proposed with a three-dimensional head computed tomographic angiography (CTA) image. Although the line thinning processing with distance transform or gray information is generally used to obtain the blood vessel center line, this method is not essentially one to obtain the center line and tends to yield extra lines depending on CTA images. In this study, the center line of the blood vessel is obtained by tracing the vessel. The blood vessel is traced by sequentially estimating the center point and direction of the blood vessel. The center point and direction of the blood vessel are estimated by taking the correlation between the blood vessel and a solid model of the blood vessel that is designed by considering noise influence. In addition, the vessel diameter is also estimated by correlating the blood vessel and the blood vessel model of which the diameter is variable. The validity of the proposed method is confirmed by experimentally applied the proposed method to an actual three-dimensional head CTA image. (author)

Three-dimensional quantum electrodynamics as an effective interaction

International Nuclear Information System (INIS)

Abdalla, E.; Carvalho Filho, F.M. de

1995-10-01

We obtain a Quantum Electrodynamics in 2 + 1 dimensions by applying a Kaluza-Klein type method of dimensional reduction to Quantum Electrodynamics in 3 + 1 dimensions rendering the model more realistic to application in solid-state systems, invariant under translations in one direction. We show that the model obtained leads to an effective action exhibiting an interesting phase structure and that the generated Chern-Simons term survives only in the broken phase. (author). 20 refs

Reinforcement learning on slow features of high-dimensional input streams.

Directory of Open Access Journals (Sweden)

Robert Legenstein

Full Text Available Humans and animals are able to learn complex behaviors based on a massive stream of sensory information from different modalities. Early animal studies have identified learning mechanisms that are based on reward and punishment such that animals tend to avoid actions that lead to punishment whereas rewarded actions are reinforced. However, most algorithms for reward-based learning are only applicable if the dimensionality of the state-space is sufficiently small or its structure is sufficiently simple. Therefore, the question arises how the problem of learning on high-dimensional data is solved in the brain. In this article, we propose a biologically plausible generic two-stage learning system that can directly be applied to raw high-dimensional input streams. The system is composed of a hierarchical slow feature analysis (SFA network for preprocessing and a simple neural network on top that is trained based on rewards. We demonstrate by computer simulations that this generic architecture is able to learn quite demanding reinforcement learning tasks on high-dimensional visual input streams in a time that is comparable to the time needed when an explicit highly informative low-dimensional state-space representation is given instead of the high-dimensional visual input. The learning speed of the proposed architecture in a task similar to the Morris water maze task is comparable to that found in experimental studies with rats. This study thus supports the hypothesis that slowness learning is one important unsupervised learning principle utilized in the brain to form efficient state representations for behavioral learning.

Three-dimensional intrafractional internal target motions in accelerated partial breast irradiation using three-dimensional conformal external beam radiotherapy.

Science.gov (United States)

Hirata, Kimiko; Yoshimura, Michio; Mukumoto, Nobutaka; Nakamura, Mitsuhiro; Inoue, Minoru; Sasaki, Makoto; Fujimoto, Takahiro; Yano, Shinsuke; Nakata, Manabu; Mizowaki, Takashi; Hiraoka, Masahiro

2017-07-01

We evaluated three-dimensional intrafractional target motion, divided into respiratory-induced motion and baseline drift, in accelerated partial breast irradiation (APBI). Paired fluoroscopic images were acquired simultaneously using orthogonal kV X-ray imaging systems at pre- and post-treatment for 23 patients who underwent APBI with external beam radiotherapy. The internal target motion was calculated from the surgical clips placed around the tumour cavity. The peak-to-peak respiratory-induced motions ranged from 0.6 to 1.5mm in all directions. A systematic baseline drift of 1.5mm towards the posterior direction and a random baseline drift of 0.3mm in the lateral-medial and cranial-caudal directions were observed. The baseline for an outer tumour cavity drifted towards the lateral and posterior directions, and that for an upper tumour cavity drifted towards the cranial direction. Moderate correlations were observed between the posterior baseline drift and the patients' physical characteristics. The posterior margin for intrafractional uncertainties was larger than 5mm in patients with greater fat thickness due to the baseline drift. The magnitude of the intrafractional motion was not uniform according to the direction, patients' physical characteristics, or tumour cavity location due to the baseline drift. Therefore, the intrafractional systematic movement should be properly managed. Copyright © 2017 Elsevier B.V. All rights reserved.

Analysis of directly driven ICF targets

International Nuclear Information System (INIS)

Velarde, G.; Aragones, J.M.; Gago, J.A.

1986-01-01

The current capabilities at DENIM for the analysis of directly driven targets are presented. These include theoretical, computational and applied physical studies and developments of detailed simulation models for the most relevant processes in ICF. The simulation of directly driven ICF targets is carried out with the one-dimensional NORCLA code developed at DENIM. This code contains two main segments: NORMA and CLARA, able to work fully coupled and in an iterative manner. NORMA solves the hydrodynamic equations in a lagrangian mesh. It has modular programs couple to it to treat the laser or particle beam interaction with matter. Equations of state, opacities and conductivities are taken from a DENIM atomic data library, generated externally with other codes that will also be explained in this work. CLARA solves the transport equation for neutrons, as well as for charged particles, and suprathermal electrons using discrete ordinates and finite element methods in the computational procedure. Parametric calculations of multilayered single-shell targets driven by heavy ion beams are also analyzed. Finally, conclusions are focused on the ongoing developments in the areas of interest such as: radiation transport, atomic physics, particle in cell method, charged particle transport, two-dimensional calculations and instabilities. (author)

Two-dimensional errors

International Nuclear Information System (INIS)

Anon.

1991-01-01

This chapter addresses the extension of previous work in one-dimensional (linear) error theory to two-dimensional error analysis. The topics of the chapter include the definition of two-dimensional error, the probability ellipse, the probability circle, elliptical (circular) error evaluation, the application to position accuracy, and the use of control systems (points) in measurements

Three dimensional graphene foam supported platinum-ruthenium bimetallic nanocatalysts for direct methanol and direct ethanol fuel cell applications

Science.gov (United States)

Kung, Chih-Chien; Lin, Po-Yuan; Xue, Yuhua; Akolkar, Rohan; Dai, Liming; Yu, Xiong; Liu, Chung-Chiun

2014-06-01

A novel composite material of hierarchically structured platinum-ruthenium (PtRu) nanoparticles grown on large surface area three dimensional graphene foam (3D GF) is reported. 3D GF was incorporated with PtRu bimetallic nanoparticles as an electrochemical nanocatalyst for methanol and ethanol oxidation. PtRu/3D GF nanocatalyst showed a higher tolerance to poisoning by CO and exhibited improved catalytic activity for both methanol oxidation reaction (MOR) and ethanol oxidation reaction (EOR). Cyclic voltammetry (CV) results and long-term cycling stability tests demonstrated that GF provided a promising platform for the development of electrochemical nanocatalysts. Specifically, PtRu/3D GF nanocatalyst showed excellent catalytic activity toward MOR and EOR compared with PtRu/Graphene (Commercial graphene), PtRu/C (Vulcan XC-72R carbon), and PtRu alone. The crystal size of PtRu on 3D GF was reduced to 3.5 nm and its active surface area was enhanced to 186.2 m2 g-1. Consequently, the MOR and EOR rates were nearly doubled on PtRu/3D GF compared to those on PtRu/Graphene.

A scaling analysis of electronic localization in two-dimensional random media

International Nuclear Information System (INIS)

Ye Zhen

2003-01-01

By an improved scaling analysis, we suggest that there may appear two possibilities concerning the electronic localization in two-dimensional random media. The first is that all electronic states are localized in two dimensions, as conjectured previously. The second possibility is that electronic behaviors in two- and three-dimensional random systems are similar, in agreement with a recent calculation based on a direct calculation of the conductance with the use of the Kubo formula. In this case, non-localized states are possible in two dimensions, and have some peculiar properties. A few predictions are proposed. Moreover, the present analysis accommodates results from the previous scaling analysis

Classifying and assembling two-dimensional X-ray laser diffraction patterns of a single particle to reconstruct the three-dimensional diffraction intensity function: resolution limit due to the quantum noise

International Nuclear Information System (INIS)

Tokuhisa, Atsushi; Taka, Junichiro; Kono, Hidetoshi; Go, Nobuhiro

2012-01-01

A new algorithm is developed for reconstructing the high-resolution three-dimensional diffraction intensity function of a globular biological macromolecule from many quantum-noise-limited two-dimensional X-ray laser diffraction patterns, each for an unknown orientation. The structural resolution is expressed as a function of the incident X-ray intensity and quantities characterizing the target molecule. A new two-step algorithm is developed for reconstructing the three-dimensional diffraction intensity of a globular biological macromolecule from many experimentally measured quantum-noise-limited two-dimensional X-ray laser diffraction patterns, each for an unknown orientation. The first step is classification of the two-dimensional patterns into groups according to the similarity of direction of the incident X-rays with respect to the molecule and an averaging within each group to reduce the noise. The second step is detection of common intersecting circles between the signal-enhanced two-dimensional patterns to identify their mutual location in the three-dimensional wavenumber space. The newly developed algorithm enables one to detect a signal for classification in noisy experimental photon-count data with as low as ∼0.1 photons per effective pixel. The wavenumber of such a limiting pixel determines the attainable structural resolution. From this fact, the resolution limit due to the quantum noise attainable by this new method of analysis as well as two important experimental parameters, the number of two-dimensional patterns to be measured (the load for the detector) and the number of pairs of two-dimensional patterns to be analysed (the load for the computer), are derived as a function of the incident X-ray intensity and quantities characterizing the target molecule

One-dimensional cuts through multidimensional potential-energy surfaces by tunable x rays

Science.gov (United States)

Eckert, Sebastian; da Cruz, Vinícius Vaz; Gel'mukhanov, Faris; Ertan, Emelie; Ignatova, Nina; Polyutov, Sergey; Couto, Rafael C.; Fondell, Mattis; Dantz, Marcus; Kennedy, Brian; Schmitt, Thorsten; Pietzsch, Annette; Odelius, Michael; Föhlisch, Alexander

2018-05-01

The concept of the potential-energy surface (PES) and directional reaction coordinates is the backbone of our description of chemical reaction mechanisms. Although the eigenenergies of the nuclear Hamiltonian uniquely link a PES to its spectrum, this information is in general experimentally inaccessible in large polyatomic systems. This is due to (near) degenerate rovibrational levels across the parameter space of all degrees of freedom, which effectively forms a pseudospectrum given by the centers of gravity of groups of close-lying vibrational levels. We show here that resonant inelastic x-ray scattering (RIXS) constitutes an ideal probe for revealing one-dimensional cuts through the ground-state PES of molecular systems, even far away from the equilibrium geometry, where the independent-mode picture is broken. We strictly link the center of gravity of close-lying vibrational peaks in RIXS to a pseudospectrum which is shown to coincide with the eigenvalues of an effective one-dimensional Hamiltonian along the propagation coordinate of the core-excited wave packet. This concept, combined with directional and site selectivity of the core-excited states, allows us to experimentally extract cuts through the ground-state PES along three complementary directions for the showcase H2O molecule.

Infinite additional symmetries in the two-dimensional conformal quantum field theory

International Nuclear Information System (INIS)

Apikyan, S.A.

1987-01-01

Additional symmetries in the two-dimensional conformal field theory, generated by currents (2,3/2,5/2) and (2,3/2,3) have been studied. It has been shown that algebra (2,3/2,5/2) is the direct product of algebras (2,3/2) and (2,5/2), and algebra (2,3/2,3) is the direct product of algebras (2,3/2) and (2,3). Associative algebra, formed by multicomponent symmetry generators of spin 3 for SO(3) has also been found

Multi-frequency direct sampling method in inverse scattering problem

Science.gov (United States)

Kang, Sangwoo; Lambert, Marc; Park, Won-Kwang

2017-10-01

We consider the direct sampling method (DSM) for the two-dimensional inverse scattering problem. Although DSM is fast, stable, and effective, some phenomena remain unexplained by the existing results. We show that the imaging function of the direct sampling method can be expressed by a Bessel function of order zero. We also clarify the previously unexplained imaging phenomena and suggest multi-frequency DSM to overcome traditional DSM. Our method is evaluated in simulation studies using both single and multiple frequencies.

Three-dimensional modeling of electron quasiviscous dissipation in guide-field magnetic reconnection

International Nuclear Information System (INIS)

Hesse, Michael; Kuznetsova, Masha; Schindler, Karl; Birn, Joachim

2005-01-01

A numerical study of guide-field magnetic reconnection in a three-dimensional model is presented. Starting from an initial, perturbed, force-free current sheet, it is shown that reconnection develops to an almost translationally invariant state, where magnetic perturbations are aligned primarily along the main current flow direction. An analysis of guide-field and electron flow signatures indicates behavior that is very similar to earlier, albeit not three-dimensional, simulations. Furthermore, a detailed investigation of electron pressure nongyrotropies in the central diffusion region confirms the major role the associated dissipation process plays in establishing the reconnection electric field

Quantum theory of two-dimensional generalized Toda lattice on bounded spatial interval

International Nuclear Information System (INIS)

Leznov, A.N.

1982-01-01

The quantization method of exactly solvable dynamical systems worked out in another paper is applied to a two-dimensional model described by the equations of generalized Toda lattice with a periodicity condition over spatial variable. The Heisenberg operators of the model are finite polynomials over the coupling constant g 2 , whose coefficients functionally depend on operators of noninteracting fields. The model has a direct relation with the string theories and reduces formally when L→infinity to two-dimensional quantum field theory described by the equations of generalized Toda lattice the formal solution of which has been found in Refs

Full three-dimensional isotropic carpet cloak designed by quasi-conformal transformation optics.

Science.gov (United States)

Silva, Daniely G; Teixeira, Poliane A; Gabrielli, Lucas H; Junqueira, Mateus A F C; Spadoti, Danilo H

2017-09-18

A fully three-dimensional carpet cloak presenting invisibility in all viewing angles is theoretically demonstrated. The design is developed using transformation optics and three-dimensional quasi-conformal mapping. Parametrization strategy and numerical optimization of the coordinate transformation deploying a quasi-Newton method is applied. A discussion about the minimum achievable anisotropy in the 3D transformation optics is presented. The method allows to reduce the anisotropy in the cloak and an isotropic medium could be considered. Numerical simulations confirm the strategy employed enabling the design of an isotropic reflectionless broadband carpet cloak independently of the incident light direction and polarization.

A Contingency Approach to Communication Skill Importance: The Impact of Occupation, Direction, and Position.

Science.gov (United States)

Di Salvo, Vincent S.; Larsen, Janet K.

1987-01-01

Examines the impact of direction and occupation on the importance of communication skills for entry-level positions in finance, management, engineering, and law. Results substantiate a three-dimensional model (based on direction, occupation, and position) for the examination and application of communication skill importance in organization. (JD)

Direct numerical simulation of homogeneous stratified rotating turbulence

Energy Technology Data Exchange (ETDEWEB)

Iida, O.; Tsujimura, S.; Nagano, Y. [Nagoya Institute of Technology, Department of Mech. Eng., Nagoya (Japan)

2005-12-01

The effects of the Prandtl number on stratified rotating turbulence have been studied in homogeneous turbulence by using direct numerical simulations and a rapid distortion theory. Fluctuations under strong stable-density stratification can be theoretically divided into the WAVE and the potential vorticity (PV) modes. In low-Prandtl-number fluids, the WAVE mode deteriorates, while the PV mode remains. Imposing rotation on a low-Prandtl-number fluid makes turbulence two-dimensional as well as geostrophic; it is found from the instantaneous turbulent structure that the vortices merge to form a few vertically-elongated vortex columns. During the period toward two-dimensionalization, the vertical vortices become asymmetric in the sense of rotation. (orig.)

Estimates of error introduced when one-dimensional inverse heat transfer techniques are applied to multi-dimensional problems

International Nuclear Information System (INIS)

Lopez, C.; Koski, J.A.; Razani, A.

2000-01-01

A study of the errors introduced when one-dimensional inverse heat conduction techniques are applied to problems involving two-dimensional heat transfer effects was performed. The geometry used for the study was a cylinder with similar dimensions as a typical container used for the transportation of radioactive materials. The finite element analysis code MSC P/Thermal was used to generate synthetic test data that was then used as input for an inverse heat conduction code. Four different problems were considered including one with uniform flux around the outer surface of the cylinder and three with non-uniform flux applied over 360 deg C, 180 deg C, and 90 deg C sections of the outer surface of the cylinder. The Sandia One-Dimensional Direct and Inverse Thermal (SODDIT) code was used to estimate the surface heat flux of all four cases. The error analysis was performed by comparing the results from SODDIT and the heat flux calculated based on the temperature results obtained from P/Thermal. Results showed an increase in error of the surface heat flux estimates as the applied heat became more localized. For the uniform case, SODDIT provided heat flux estimates with a maximum error of 0.5% whereas for the non-uniform cases, the maximum errors were found to be about 3%, 7%, and 18% for the 360 deg C, 180 deg C, and 90 deg C cases, respectively

Solitons in one-dimensional antiferromagnetic chains

International Nuclear Information System (INIS)

Pires, A.S.T.; Talim, S.L.; Costa, B.V.

1989-01-01

We study the quantum-statistical mechanics, at low temperatures, of a one-dimensional antiferromagnetic Heisenberg model with two anisotropies. In the weak-coupling limit we determine the temperature dependences of the soliton energy and the soliton density. We have found that the leading correction to the sine-Gordon (SG) expression for the soliton density and the quantum soliton energy comes from the out-of-plane magnon mode, not present in the pure SG model. We also show that when an external magnetic field is applied, the chain supports a new type of kink, where the sublattices rotate in opposite directions

Novel investigation of the different Omni-direction-guide-vane angles effects on the urban vertical axis wind turbine output power via three-dimensional numerical simulation

International Nuclear Information System (INIS)

Shahizare, B.; Nik-Ghazali, N.; Chong, W.T.; Tabatabaeikia, S.; Izadyar, Nima; Esmaeilzadeh, Alireza

2016-01-01

Highlights: • Investigation of the Omni-direction-guide-vane impacts on the VAWT performance. • Obtain the best position of the guide vane angles in order to achieve the maximum performance. • Validation of the 3D computational fluid dynamics with experimental data. • Acquire the optimal Omni-direction-guide-vane based on numerical simulation results. - Abstract: The aim of this study is to present the effects of different Omni-direction-guide-vane (ODGV) angles on the performance of the vertical axis wind turbine (VAWT). For this purpose, five different straight-bladed VAWTs have been simulated via three-dimensional (3D) computational fluid dynamics (CFD). Hence, the VAWT without ODGV covering, were simulated and validated via CFD and experimental fluid dynamics (EFD) data, respectively in the first step. Indeed, grid and time step independency test as well as the effect of domain size, have been conducted and a suitable agreement was found based on comparison of the CFD and EFD results. In the next step, the VAWT was shrouded by ODGV cover and the whole system was simulated for 52 angles of the ODGV in four different tip speed ratios (TSR), to investigate the impact of guide vanes angles on the VAWT performance. Results of this study indicated that output power of the VAWT with α = 20° and β = 55° ODGV guide vanes, was improved 40.9%, 36.5%, 35.3% and 33.2%, respectively in four different TSR including 0.745, 1.091, 1.901 and 2.53.