These are representative sample records from Science.gov related to your search topic.
For comprehensive and current results, perform a real-time search at Science.gov.
1

Observed octameric assembly of a Plasmodium yoelii peroxiredoxin can be explained by the replacement of native "ball-and-socket" interacting residues by an affinity tag.  

PubMed

Peroxiredoxins (Prxs) are ubiquitous and efficient antioxidant enzymes crucial for redox homeostasis in most organisms, and are of special importance for disease-causing parasites that must protect themselves against the oxidative weapons of the human immune system. Here, we describe reanalyses of crystal structures of two Prxs from malaria parasites. In addition to producing improved structures, we provide normalizing explanations for features that had been noted as unusual in the original report of these structures (Qiu et al., BMC Struct Biol 2012;12:2). Most importantly, we provide evidence that the unusual octameric assembly seen for Plasmodium yoelii Prx1a is not physiologically relevant, but arises because the structure is not of authentic P. yoelii Prx1a, but a variant we designate PyPrx1a(N*) that has seven native N-terminal residues replaced by an affinity tag. This N-terminal modification disrupts a previously unrecognized, hydrophobic "ball-and-socket" interaction conserved at the B-type dimer interface of Prx1 subfamily enzymes, and is accommodated by a fascinating two-residue "?-slip" type register shift in the ?-strand association at a dimer interface. The resulting change in the geometry of the dimer provides a simple explanation for octamer formation. This study illustrates how substantive impacts can occur in protein variants in which native residues have been altered. PMID:23934758

Gretes, Michael C; Karplus, P Andrew

2013-10-01

2

Observed octameric assembly of a Plasmodium yoelii peroxiredoxin can be explained by the replacement of native "ball-and-socket" interacting residues by an affinity tag  

PubMed Central

Peroxiredoxins (Prxs) are ubiquitous and efficient antioxidant enzymes crucial for redox homeostasis in most organisms, and are of special importance for disease-causing parasites that must protect themselves against the oxidative weapons of the human immune system. Here, we describe reanalyses of crystal structures of two Prxs from malaria parasites. In addition to producing improved structures, we provide normalizing explanations for features that had been noted as unusual in the original report of these structures (Qiu et al., BMC Struct Biol 2012;12:2). Most importantly, we provide evidence that the unusual octameric assembly seen for Plasmodium yoelii Prx1a is not physiologically relevant, but arises because the structure is not of authentic P. yoelii Prx1a, but a variant we designate PyPrx1aN* that has seven native N-terminal residues replaced by an affinity tag. This N-terminal modification disrupts a previously unrecognized, hydrophobic “ball-and-socket” interaction conserved at the B-type dimer interface of Prx1 subfamily enzymes, and is accommodated by a fascinating two-residue “?-slip” type register shift in the ?-strand association at a dimer interface. The resulting change in the geometry of the dimer provides a simple explanation for octamer formation. This study illustrates how substantive impacts can occur in protein variants in which native residues have been altered. PMID:23934758

Gretes, Michael C; Karplus, P Andrew

2013-01-01

3

The structure of CrgA from Neisseria meningitidis reveals a new octameric assembly state for LysR transcriptional regulators  

Microsoft Academic Search

LysR-type transcriptional regulators (LTTRs) form the largest family of bacterial regulators acting as both auto-repressors and activators of target promoters, controlling operons involved in a wide variety of cellular processes. The LTTR, CrgA, from the human pathogen Neisseria meningitidis, is upregulated during bacterial-host cell contact. Here, we report the crystal structures of both regu- latory domain and full-length CrgA, the

Sarah Sainsbury; Jingshan Ren; Robert J. Gilbert; Nigel J. Saunders; Carol V. Robinson; David I. Stuart; Raymond J. Owens

2009-01-01

4

Iron Binding at Specific Sites within the Octameric HbpS Protects Streptomycetes from Iron-Mediated Oxidative Stress  

PubMed Central

The soil bacterium Streptomyces reticuli secretes the octameric protein HbpS that acts as a sensory component of the redox-signalling pathway HbpS-SenS-SenR. This system modulates a genetic response on iron- and haem-mediated oxidative stress. Moreover, HbpS alone provides this bacterium with a defence mechanism to the presence of high concentrations of iron ions and haem. While the protection against haem has been related to its haem-binding and haem-degrading activity, the interaction with iron has not been studied in detail. In this work, we biochemically analyzed the iron-binding activity of a set of generated HbpS mutant proteins and present evidence showing the involvement of one internal and two exposed D/EXXE motifs in binding of high quantities of ferrous iron, with the internal E78XXE81 displaying the tightest binding. We additionally show that HbpS is able to oxidize ferrous to ferric iron ions. Based on the crystal structure of both the wild-type and the mutant HbpS-D78XXD81, we conclude that the local arrangement of the side chains from the glutamates in E78XXE81 within the octameric assembly is a pre-requisite for interaction with iron. The data obtained led us to propose that the exposed and the internal motif build a highly specific route that is involved in the transport of high quantities of iron ions into the core of the HbpS octamer. Furthermore, physiological studies using Streptomyces transformants secreting either wild-type or HbpS mutant proteins and different redox-cycling compounds led us to conclude that the iron-sequestering activity of HbpS protects these soil bacteria from the hazardous side effects of peroxide- and iron-based oxidative stress. PMID:24013686

Wedderhoff, Ina; Kursula, Inari; Groves, Matthew R.; Ortiz de Orue Lucana, Dario

2013-01-01

5

Singular over-representation of an octameric palindrome, HIP1, in DNA from many cyanobacteria.  

PubMed Central

An octameric palindrome (5'-GCGATCGC-3') is abundant in cyanobacterial sequences within databases (GenBank/EMBL) and was designated HIP1 (highly iterated palindrome). The frequency of occurrence of all 256 octameric palindromes has now been determined in sub-databases revealing large and unique over-representation of HIP1 in cyanobacterial entries. DNA sequences from other bacteria were searched for any over-represented octameric palindromes analogous to HIP1. Only two sequences were identified, in the genomes of a thermophile and halophilic archaebacteria, although these were less abundant than HIP1 in cyanobacteria and relate to codon usage. To test the proposed widespread distribution of HIP1 in DNA from the cyanobacterium Synechococcus PCC 6301, randomly selected genomic clones were partly sequenced. HIP1 constituted 2.5% of the novel sequences, equivalent to a site on average once every 320 nucleotides. An oligonucleotide including HIP1 was also tested in PCR. Multiple products were obtained using template DNA from cyanobacterial strains in which HIP1 is abundant in known sequences, and some strains generated characteristic HIP-PCR banding patterns. However, analysis of DNA from one strain (not previously represented in databases) by random sequencing, HIP-PCR and Pvul digestion, confirms that not all cyanobacterial genomes are rich in HIP1. Images PMID:7708486

Robinson, N J; Robinson, P J; Gupta, A; Bleasby, A J; Whitton, B A; Morby, A P

1995-01-01

6

Expression of active octameric chicken cardiac mitochondrial creatine kinase in Escherichia coli.  

PubMed Central

Sarcomeric mitochondrial creatine kinase (Mib-CK) of chicken was expressed in Escherichia coli as a soluble enzyme by using an inducible phage-T7 promoter. Up to one third of the protein in E. coli extracts consisted of soluble recombinant Mib-CK in an enzymically active form. Approx. 20 mg of nearly-homogenous Mib-CK was isolated in a two-step isolation procedure starting with 1 litre of isopropyl beta-D-thiogalactopyranoside-induced E. coli culture, whereas previous attempts to express other CK genes in E. coli have resulted in 20-fold lower yields and inclusion-body formation. Selection of the Mib-CK expression plasmid on media containing kanamycin rather than ampicillin extended the time period of maximal Mib-CK expression. Recombinant Mib-CK displayed an identical N-terminal amino acid sequence, identical Km for phosphocreatine and Vmax. values, the same electrophoretic behaviour and the same immunological cross-reactivity as the native enzyme isolated from chicken heart mitochondria. The recombinant Mib-CK had the same molecular mass as native chicken Mib-CK in m.s. analysis, indicating that post-translational modification of the enzyme in chicken tissue does not occur. As judged by gel-permeation chromatography and electron microscopy, recombinant enzyme formed predominantly octameric oligomers with the same overall structure as the chicken heart enzyme. Furthermore, the enzymes isolated from both sources formed protein crystals of space group P42(1)2, when grown in the absence of ATP, with one Mi-CK octamer per asymmetric unit. The indistinguishable X-ray-diffraction patterns indicate identical structures for the native and recombinant proteins. Images Fig. 1. Fig. 3. Fig. 4. PMID:1471992

Furter, R; Kaldis, P; Furter-Graves, E M; Schnyder, T; Eppenberger, H M; Wallimann, T

1992-01-01

7

Conformational States of Macromolecular Assemblies Explored by Integrative Structure Calculation  

PubMed Central

Summary A detailed description of macromolecular assemblies in multiple conformational states can be very valuable for understanding cellular processes. At present, structural determination of most assemblies in different biologically relevant conformations cannot be achieved by a single technique and thus requires an integrative approach that combines information from multiple sources. Different techniques require different computational methods to allow efficient and accurate data processing and analysis. Here, we summarize the latest advances and future challenges in computational methods that help the interpretation of data from two techniques—mass spectrometry and three-dimensional cryo-electron microscopy (with focus on alignment and classification of heterogeneous subtomograms from cryo-electron tomography). We evaluate how new developments in these two broad fields will lead to further integration with atomic structures to broaden our picture of the dynamic behavior of assemblies in their native environment. PMID:24010709

Thalassinos, Konstantinos; Pandurangan, Arun Prasad; Xu, Min; Alber, Frank; Topf, Maya

2013-01-01

8

Serum Amyloid A 2.2 Refolds into a Octameric Oligomer that Slowly Converts to a More Stable Hexamer  

PubMed Central

1Serum Amyloid A (SAA) is an inflammatory protein predominantly bound to high-density lipoprotein in plasma and presumed to play various biological and pathological roles. We previously found that the murine isoform SAA2.2 exists in aqueous solution as a marginally stable hexamer at 4-20°C, but becomes an intrinsically disordered protein at 37°C. Here we show that when urea-denatured SAA2.2 is dialyzed into buffer (pH 8.0, 4°C), it refolds mostly into an octameric species. The octamer transitions to the hexameric structure upon incubation from days to weeks at 4°C, depending on the SAA2.2 concentration. Thermal denaturation of the octamer and hexamer monitored by circular dichroism showed that the octamer is ~10°C less stable, with a denaturation mid point of ~22°C. Thus, SAA2.2 becomes kinetically trapped by refolding into a less stable, but more kinetically accessible octameric species. The ability of SAA2.2 to form different oligomeric species in vitro along with its marginal stability, suggest that the structure of SAA might be modulated in vivo to form different biologically relevant species. PMID:21439938

Wang, Yun; Srinivasan, Saipraveen; Ye, Zhuqiu; Aguilera, J. Javier; Lopez, Maria M.; Colón, Wilfredo

2011-01-01

9

Multimeric assembly and biochemical characterization of the Trax/Translin endonuclease complex  

PubMed Central

Trax/Translin heteromers, also known as C3PO, have been proposed to activate RNA-induced silencing complex (RISC) by facilitating endonucleolytic cleavage of the siRNA passenger strand. We report on the crystal structure of hexameric Drosophila C3PO formed by truncated Translin and Trax, along with electron microscopic and mass spectrometric studies on octameric C3PO formed by full-length Translin and Trax. Our studies establish that Trax adopts the Translin fold, possesses catalytic centers essential for C3PO’s endoribonuclease activity and interacts extensively with Translin to form an octameric assembly. The catalytic pockets of Trax subunits are located within the interior chamber of the octameric scaffold. Truncated C3PO, like full-length, exhibits endoribonuclease activity leaving 3? hydroxyl-cleaved ends. We have measured the catalytic activity of C3PO and shown it to cleave near stoichiometric amounts of substrate per second. PMID:21552261

Tian, Yuan; Simanshu, Dhirendra K.; Ascano, Manuel; Diaz-Avalos, Ruben; Park, Ah Young; Juranek, Stefan A.; Rice, William J.; Yin, Qian; Robinson, Carol V.; Tuschl, Thomas; Patel, Dinshaw J.

2011-01-01

10

Synthesis and crystallographic characterization of an octameric water complex, (H{sub 2}O){sub 8}  

SciTech Connect

Small water clusters are the subject of considerable theoretical and experimental scrutiny and include a recently isolated water decamer. A detailed understanding of the numerous possible structures and stabilities is important for obtaining insight into the nature of water--water interactions in diverse environments. Of particular interest are octameric water clusters, (H{sub 2}O){sub 8}. A two-to-one combination in acetonitrile of {kappa}{sup 4}-[1,2-bis(2-oxy-2-methylpropanamido)-4,5-dimethoxybenzene]cobaltate(III), [A]{sup {minus}}, with bis-{kappa}{sup 3}-(2,6-diacetamidopyridine)cobalt(II), [B]{sup 2+}, yields the crystalline solvate, [A{sub 2}B]{center_dot}(CH{sub 3}CN){sub 4}. On treatment with humid air for 10 to 12 days, [A{sub 2}B]{center_dot}(CH{sub 3}CN){sub 4} forms the [A{sub 2}B](H{sub 2}O){sub 8} complex without crystal decay; both species have been crystallographically characterized.

Blanton, W.B.; Gordon-Wylie, S.W.; Collins, T.J. [Carnegie Mellon Univ., Pittsburgh, PA (United States). Dept. of Chemistry] [Carnegie Mellon Univ., Pittsburgh, PA (United States). Dept. of Chemistry; Clark, G.R. [Univ. of Auckland (New Zealand)] [Univ. of Auckland (New Zealand); Jordan, K.D.; Wood, J.T. [Univ. of Pittsburgh, PA (United States)] [Univ. of Pittsburgh, PA (United States); Geiser, U. [Argonne National Lab., IL (United States). Chemistry and Materials Science Div.] [Argonne National Lab., IL (United States). Chemistry and Materials Science Div.

1999-04-14

11

Penn State Chemical Engineering Self-Assembly, Nanoscience, Colloids,  

E-print Network

Multiscale Theory and Simulation #12;Polymers and soft materials: organic solar cells, organic thin-film photovoltaics2 Self-assembled block copolymer solar cells1 Organic thin film transistors 100 µm Group approaches #12;#12;Structure-Property Relations: Synthesis, Small-Angle Scattering, Dielectric Spectroscopy

Giles, C. Lee

12

Management and Labor Relations Techniques of Japanese-Owned Automotive Assembly Plants in the United States  

E-print Network

This field project involves a study of the Japanese-owned automotive assembly plants, or “transplants,” in the United States and the management and labor-relations techniques that have made them successful. The management and labor...

Pitney, Paul

2005-12-16

13

Solid-State NMR Studies of HIV-1 Capsid Protein Assemblies  

SciTech Connect

In mature HIV-1 virions, the 26.6 kDa CA protein is assembled into a characteristic cone-shaped core (capsid) that encloses the RNA viral genome. The assembled capsid structure is best described by a fullerene cone model that is made up from a hexameric lattice containing a variable number of CA pentamers, thus allowing for closure of tubular or conical structures. In this paper, we present a solid-state NMR analysis of the wild-type HIV-1 CA protein, prepared as conical and spherical assemblies that are stable and are not affected by magic angle spinning of the samples at frequencies between 10 and 25 kHz. Multidimensional homo- and heteronuclear correlation spectra of CA assemblies of uniformly 13C,15Nlabeled CA exhibit narrow lines, indicative of the conformational homogeneity of the protein in these assemblies. For the conical assemblies, partial residue-specific resonance assignments were obtained. Analysis of the NMR spectra recorded for the conical and spherical assemblies indicates that the CA protein structure is not significantly different in the different morphologies. The present results demonstrate that the assemblies of CA protein are amenable to detailed structural analysis by solid-state NMR spectroscopy.

Han, Yun; Ahn, Jinwoo; Concel, Jason; Byeon, In-Ja L.; Gronenborn, Angela M.; Yang, Jun; Polenova, Tatyana E.

2010-02-17

14

Adsorption states of the self-assembly of NH3 molecules on the Si(001) surface  

Microsoft Academic Search

Adsorption states of the self-assembly of NH3 molecules on the Si(001) surface are investigated using density-functional theory calculations. H-bond interactions between incoming and adsorbed NH3 molecules produce a strong attractive potential field for the incoming molecules. Induced by the H bonds, physisorption states are formed on the adsorbed NH3. Molecular adsorption states are formed on a buckled-down Si atom near

Yong-Sung Kim; Ja-Yong Koo; Hanchul Kim

2009-01-01

15

Premitotic assembly of human CENPs -T and -W switches centromeric chromatin to a mitotic state.  

PubMed

Centromeres are differentiated chromatin domains, present once per chromosome, that direct segregation of the genome in mitosis and meiosis by specifying assembly of the kinetochore. They are distinct genetic loci in that their identity in most organisms is determined not by the DNA sequences they are associated with, but through specific chromatin composition and context. The core nucleosomal protein CENP-A/cenH3 plays a primary role in centromere determination in all species and directs assembly of a large complex of associated proteins in vertebrates. While CENP-A itself is stably transmitted from one generation to the next, the nature of the template for centromere replication and its relationship to kinetochore function are as yet poorly understood. Here, we investigate the assembly and inheritance of a histone fold complex of the centromere, the CENP-T/W complex, which is integrated with centromeric chromatin in association with canonical histone H3 nucleosomes. We have investigated the cell cycle regulation, timing of assembly, generational persistence, and requirement for function of CENPs -T and -W in the cell cycle in human cells. The CENP-T/W complex assembles through a dynamic exchange mechanism in late S-phase and G2, is required for mitosis in each cell cycle and does not persist across cell generations, properties reciprocal to those measured for CENP-A. We propose that the CENP-A and H3-CENP-T/W nucleosome components of the centromere are specialized for centromeric and kinetochore activities, respectively. Segregation of the assembly mechanisms for the two allows the cell to switch between chromatin configurations that reciprocally support the replication of the centromere and its conversion to a mitotic state on postreplicative chromatin. PMID:21695110

Prendergast, Lisa; van Vuuren, Chelly; Kaczmarczyk, Agnieszka; Doering, Volker; Hellwig, Daniela; Quinn, Nadine; Hoischen, Christian; Diekmann, Stephan; Sullivan, Kevin F

2011-06-01

16

Premitotic Assembly of Human CENPs -T and -W Switches Centromeric Chromatin to a Mitotic State  

PubMed Central

Centromeres are differentiated chromatin domains, present once per chromosome, that direct segregation of the genome in mitosis and meiosis by specifying assembly of the kinetochore. They are distinct genetic loci in that their identity in most organisms is determined not by the DNA sequences they are associated with, but through specific chromatin composition and context. The core nucleosomal protein CENP-A/cenH3 plays a primary role in centromere determination in all species and directs assembly of a large complex of associated proteins in vertebrates. While CENP-A itself is stably transmitted from one generation to the next, the nature of the template for centromere replication and its relationship to kinetochore function are as yet poorly understood. Here, we investigate the assembly and inheritance of a histone fold complex of the centromere, the CENP-T/W complex, which is integrated with centromeric chromatin in association with canonical histone H3 nucleosomes. We have investigated the cell cycle regulation, timing of assembly, generational persistence, and requirement for function of CENPs -T and -W in the cell cycle in human cells. The CENP-T/W complex assembles through a dynamic exchange mechanism in late S-phase and G2, is required for mitosis in each cell cycle and does not persist across cell generations, properties reciprocal to those measured for CENP-A. We propose that the CENP-A and H3-CENP-T/W nucleosome components of the centromere are specialized for centromeric and kinetochore activities, respectively. Segregation of the assembly mechanisms for the two allows the cell to switch between chromatin configurations that reciprocally support the replication of the centromere and its conversion to a mitotic state on postreplicative chromatin. PMID:21695110

Prendergast, Lisa; van Vuuren, Chelly; Kaczmarczyk, Agnieszka; Doering, Volker; Hellwig, Daniela; Quinn, Nadine; Hoischen, Christian; Diekmann, Stephan; Sullivan, Kevin F.

2011-01-01

17

Revealing molecular self-assembly and geometry of non-covalent halogen bonding by solid-state NMR spectroscopyw  

E-print Network

Revealing molecular self-assembly and geometry of non-covalent halogen bonding by solid-state NMR813237b We report a new spectroscopic fingerprint of intermolecular contacts in halogen bond-driven self-assembling aggregates and a precise determination of intermolecular NÁ Á ÁI distances in microcrystalline samples. Non-covalent

18

Detection and switching of the oxidation state of Fe in a self-assembled monolayer  

NASA Astrophysics Data System (ADS)

A self-assembled monolayer of ferrocene-capped alkanethiols is produced in two stable oxidation states of Fe (Fe 2+ and Fe 3+). These oxidation states are detected with sub-monolayer sensitivity by the fine structure of the Fe2p absorption edge. The native Fe 2+ ferrocene layer is converted chemically to Fe 3+, and the Fe 3+ layer can be transformed back to Fe 2+ or possibly Fe 0 by irradiation with soft X-rays. The results have implications on switching mechanisms in molecular electronics.

Zheng, Fan; Pérez-Dieste, V.; McChesney, J. L.; Luk, Yan-Yeung; Abbott, Nicholas L.; Himpsel, F. J.

2005-08-01

19

Steady-State Thermal Performance Evaluation of Steel-Framed Wall Assembly with Local Foam Insulation  

SciTech Connect

During January and May, 2009, two configurations of steel-framed walls constructed with conventional 2 4 steel studs insulated with R-19 ~14cm. (5.5-in. thick) and R-13 ~9cm. (3.5-in. thick) fiberglass insulation batts were tested in the Oak Ridge National Laboratory (ORNL) guarded hot-box using ASTM C1363 test procedure. The first test wall used conventional 2 4 steel studs insulated with 2.5-cm. (1-in.) thick foam profiles, called stud snugglers. These stud snugglers converted the 2 4 wall assembly into a 2 6 assembly allowing application of R-19 fiberglass insulation. The second wall tested for comparison was a conventional 2 4 steel stud wall using R-13 insulation batts. Further, numerical simulations were performed in order to evaluate the steady-state thermal performance of various wood- and steel-framed wall assemblies. The effects of adding the stud-snugglers to the wood and steel studs were also investigated numerically. Different combinations of insulation and framing factor were used in the simulations.

Kosny, Jan [ORNL] [ORNL; Biswas, Kaushik [ORNL] [ORNL; Childs, Phillip W [ORNL] [ORNL

2010-01-01

20

Self-assembled nanowire array capacitors: capacitance and interface state profile.  

PubMed

Direct characterization of the capacitance and interface states is very important for understanding the electronic properties of a nanowire transistor. However, the capacitance of a single nanowire is too small to precisely measure. In this work we have fabricated metal-oxide-semiconductor capacitors based on a large array of self-assembled Si nanowires. The capacitance and conductance of the nanowire array capacitors are directly measured and the interface state profile is determined by using the conductance method. We demonstrate that the nanowire array capacitor is an effective platform for studying the electronic properties of nanoscale interfaces. This approach provides a useful and efficient metrology for the study of the physics and device properties of nanoscale metal-oxide-semiconductor structures. PMID:24584362

Li, Qiliang; Xiong, Hao D; Liang, Xuelei; Zhu, Xiaoxiao; Gu, Diefeng; Ioannou, Dimitris E; Baumgart, Helmut; Richter, Curt A

2014-04-01

21

Self-assembled nanowire array capacitors: capacitance and interface state profile  

NASA Astrophysics Data System (ADS)

Direct characterization of the capacitance and interface states is very important for understanding the electronic properties of a nanowire transistor. However, the capacitance of a single nanowire is too small to precisely measure. In this work we have fabricated metal-oxide-semiconductor capacitors based on a large array of self-assembled Si nanowires. The capacitance and conductance of the nanowire array capacitors are directly measured and the interface state profile is determined by using the conductance method. We demonstrate that the nanowire array capacitor is an effective platform for studying the electronic properties of nanoscale interfaces. This approach provides a useful and efficient metrology for the study of the physics and device properties of nanoscale metal-oxide-semiconductor structures.

Li, Qiliang; Xiong, Hao D.; Liang, Xuelei; Zhu, Xiaoxiao; Gu, Diefeng; Ioannou, Dimitris E.; Baumgart, Helmut; Richter, Curt A.

2014-04-01

22

Encapsulated discrete octameric water cluster, 1D water tape, and 3D water aggregate network in diverse MOFs based on bisimidazolium ligands  

NASA Astrophysics Data System (ADS)

Four new metal-organic frameworks, [Zn(2-mBIM)2(SO3CF3)2·(H2O)4] (1), [Zn(BMIE)(1,4-BDC)]·(H2O)3 (2), [Cd(BIM)2(OH)(H2O)2(PF6)]·(H2O)4 (3), and [Cd(PA-BIM)2 (ClO4)2]·11.33H2O (4) (2-mBIM = bis(2-methylimidazol-1-yl)methane, BMIE = 1,2-bis[1-(2-methylimidazole)-diethoxy]ethane, BIM = bis(imidazol-1-yl)methane, and PA-BIM = 1,1-bis [(2-phenylazo)imidazol-1-yl]methane) have been prepared and structurally characterized. Complex 1 exhibits an infinite 1D cationic beaded-chain structure, which encapsulated discrete octameric water clusters that are comprised of a chair-like hexameric water cluster with two extra water molecules dangling on two diagonal vertices of the chair. Complex 2 forms a 1D infinite zigzag metal-organic chain structure with a 1D T4(0)A(4) water tape. Complexes 3 show a 2D grid-like sheet structure with the 1D water tape T4(0)A(0)2(0) motif. Complex 4 is a porous 3D MOF with tetrahedron-coordinated Cd(II) centers and trans-conformation PA-BIM ligands. These holes are occupied by a fascinating three-dimensional water clathrate network, which consists of cage-shaped structural tetradecameric water cluster (H2O)14 units and six independent bridged water molecules. The results suggest that the bisimidazolium ligands and anions play crucial roles in the formation of the different host structures and different guest water aggregations. Additionally, the thermal stabilities and photoluminescence spectra of the complexes have been discussed.

Shi, Ruo-Bing; Pi, Min; Jiang, Shuang-Shuang; Wang, Yuan-Yuan; Jin, Chuan-Ming

2014-08-01

23

19 CFR 10.25 - Textile components cut to shape in the United States and assembled abroad.  

...2014-04-01 2014-04-01 false Textile components cut to shape in the United...United States Components § 10.25 Textile components cut to shape in the United States and assembled abroad. Where a textile component is cut to shape (but...

2014-04-01

24

19 CFR 10.25 - Textile components cut to shape in the United States and assembled abroad.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Textile components cut to shape in the United...United States Components § 10.25 Textile components cut to shape in the United States and assembled abroad. Where a textile component is cut to shape (but...

2012-04-01

25

19 CFR 10.25 - Textile components cut to shape in the United States and assembled abroad.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Textile components cut to shape in the United...United States Components § 10.25 Textile components cut to shape in the United States and assembled abroad. Where a textile component is cut to shape (but...

2013-04-01

26

19 CFR 10.25 - Textile components cut to shape in the United States and assembled abroad.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Textile components cut to shape in the United...United States Components § 10.25 Textile components cut to shape in the United States and assembled abroad. Where a textile component is cut to shape (but...

2011-04-01

27

19 CFR 10.25 - Textile components cut to shape in the United States and assembled abroad.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Textile components cut to shape in the United...United States Components § 10.25 Textile components cut to shape in the United States and assembled abroad. Where a textile component is cut to shape (but...

2010-04-01

28

Solid state assemblies and photophysical characteristics of linear and bent-core ?-conjugated oligophenylenevinylenes.  

PubMed

New classes of luminescent linear, bent-core, and star-shaped oligophenylenevinylenes (OPVs) having 1,4-para and 1,3-meta rigid aromatic cores were designed and developed. 3-Pentadecylphenol, a renewable resource molecule, was chosen as the flexible unit at the longitudinal or middle position of the OPV aromatic core for solid state ordering. Depending upon the nature of the ?-core, the OPVs exhibited either mosaic-type liquid crystalline textures or spherulitic crystalline solids. The enthalpies of melting transitions revealed that the bent-core OPV structure showed enhanced solid state packing compared to linear or star-shaped OPVs. Small and wide-angle X-ray diffraction analysis confirmed layered-like assemblies in OPV molecules. Photophysical experiments such as excitation, emission, and time-resolved fluorescence decay dynamics were carried out to trace the molecular self-organization of OPV chromophores. Time correlated single photon counting technique (TCSPC) luminescent decay profiles and decay lifetimes (?1 and ?2 values) revealed that the OPV chromophores showed faster exciton decay in the tightly packed bent-core structure. The weakly packed star-shaped OPV showed enhanced excited state luminescence stability up to 10 ns. A direct correlation between the OPV chemical structure, solid state ordering, and photophysical characteristics was established. PMID:23716506

Singh, Harpreet; Balamurugan, A; Jayakannan, M

2013-06-26

29

Quasi-solid-state optical logic devices based on redox polymer nanosheet assembly.  

PubMed

We report fabrication of a quasi-solid-state optical logic gate based on a polymer nanosheet photodiode. Two amphiphilic copolymers, p(DDA/Ru) and p(DDA/Fc), which respectively have a ruthenium dipyridyl complex and a ferrocene derivative as a redox molecule, are synthesized to produce redox polymer nanosheets. To construct polymer nanosheet photodiodes, two redox polymer nanosheets were assembled onto an indium-tinoxide (ITO) electrode in a tailor-made manner. The ITO electrode was connected with a counter electrode using an agarose gel electrolyte. The simple two-electrode system performs as a quasi-solid-state polymer nanosheet photodiode (QS-PNP). The photocurrent flow direction of QS-PNP can be controlled to be anodic or be cathodic by changing the deposition order of the redox polymer nanosheets. The anodic and cathodic QS-PNPs were applied to construct optical OR and XOR logic gates. The OR logic gate was fabricated by connecting the anodic and cathodic QS-PNP in a series; XOR logic was fabricated by connecting two anodic QS-PNPs in series. In optical logic gates, excitations of p(DDA/Ru) were used as input signals, and photocurrent was used as an output signal. These optical logic gates operate in a quasi-solid-state in a simple two-electrode configuration, which facilitates integration of the logic elements. PMID:19441809

Matsui, Jun; Abe, Kenichi; Mitsuishi, Masaya; Aoki, Atsushi; Miyashita, Tokuji

2009-09-15

30

Affordability of Higher Education: California and Other States. Presentation to the Assembly Higher Education Committee. Report 11-01  

ERIC Educational Resources Information Center

This is a summary of a presentation to the Assembly Higher Education Committee on college fee and total cost comparisons of California public universities with comparator universities in other states. This summary also includes grant award estimates and net cost of college by family income.

Jones, Jessika

2011-01-01

31

Long-term self-assembly of inorganic layered materials influenced by the local states of the interlayer cations.  

PubMed

A wide variety of parameters as, e.g., temperature, humidity, particle size, and cation state are known to influence the agglomeration process of two-dimensional (2D) nanosheets, called self-assembly, in inorganic layered materials. The detailed studies on which parameters are decisive and how they influence the self-assembly, however, have not been performed yet. Here, the long-term self-assembly was studied for layered stevensite and hectorite, and compared with our previous data of saponite for elucidating an influence of local states of the interlayer cations. The results were analyzed with respect to a recently established rheological model, in which 2D nanosheets migrate parallel to the layer direction aided by water molecules as lubricants [K. Sato et al., J. Phys. Chem. C, 2012, 116, 22954]. With decreasing the strength of the local electric fields facing to the interlayer spaces, cation positions split into two or three, which makes the distribution of water molecules more uniformly. These water molecules enhance the rheological motion of the 2D nanosheets parallel to the layer direction, thus accelerating the self-assembly process. PMID:24770790

Sato, Kiminori; Numata, Kazuomi; Dai, Weili; Hunger, Michael

2014-06-14

32

Conserved features of intermediates in amyloid assembly determine their benign or toxic states  

E-print Network

Some amyloid-forming polypeptides are associated with devastating human diseases and others provide important biological functions. For both, oligomeric intermediates appear during amyloid assembly. Currently we have few ...

Krishnan, Rajaraman

33

Synthesis and solution state self-assembly of linear-dendritic block copolymers  

E-print Network

Linear-dendritic block copolymers consisting of a poly(styrene) linear block and poly(amidoamine) dendrimer block were synthesized and examined for their ability to self-assemble in both aqueous environments and organic/aqueous ...

Stokes, Kristoffer Keith

2007-01-01

34

An Amyloid Organelle: Solid State NMR Evidence for Cross-Beta Assembly of Gas Vesicles  

E-print Network

Functional amyloids have been identified in a wide range of organisms, taking on a variety of biological roles and being controlled by remarkable mechanisms of directed assembly. Here, we report that amyloid fibrils ...

Bayro, Marvin J.

35

Excited state dynamics and structures of functionalized phthalocyanines. 1. Self-regulated assembly of zinc helicenocyanine.  

PubMed

Recently synthesized zinc helicenocyanine (ZnHc), where four helicene groups are fused with a phthalocyanine (Pc) core through all-carbon linkages, exhibits an unusually strong tendency of forming soluble molecular aggregates in organic solvents. The aggregation results in a strong optical absorption across most of the visible region, which is drastically different from that of its monomer. The aggregation is suppressed by dissolving ZnHc in a liquid crystal, octylbiphenylcarbonitrile (OBCN), where the monomer ZnHc dominates and exhibits a typical optical absorption spectrum of monomeric zinc phthalocyanine, except red shift in both Q- and B- bands due to pi-conjugation expansion. This study correlates optical properties and excited state dynamics of ZnHc with intra- and intermolecular electronic interactions, using quantum mechanical calculations and ultrafast transient absorption spectroscopy. Structural details of the aggregates are revealed by small-angle X-ray scattering (SAXS) to be uniformly dimers with alkoxy chains wrapped around the core of a face-to-face dimer. The results suggest that while the peripheral helicene moieties in ZnHc are electronically coupled to the Pc core via expansion of the pi-conjugation of the macrocycle, the coupling is attenuated by the "lock washer" conformation of the nonplanar peripheral helicenes which prevents pi-conjugation throughout the entire macrocycle. The interplay between pi-conjugation expansion in the macrocyle plane and the pi-pi stacking out of the macrocyle plane produces a structure that facilitates the unique optical properties and self-regulated assembly into nanoscale structures in solution. These novel optical properties are explored for potential applications in various areas. PMID:16853112

Chen, Lin X; Shaw, George B; Tiede, David M; Zuo, Xiaobing; Zapol, Peter; Redfern, Paul C; Curtiss, Larry A; Sooksimuang, Thanasat; Mandal, Braja K

2005-09-01

36

Solid-State Nanostructured Materials from Self-Assembly of a Globular Protein-Polymer Diblock Copolymer  

PubMed Central

Self-assembly of three-dimensional solid-state nanostructures containing approximately 33% by weight globular protein is demonstrated using a globular protein-polymer diblock copolymer, providing a route to direct nanopatterning of proteins for use in bioelectronic and biocatalytic materials. A mutant red fluorescent protein, mCherryS131C, was prepared by incorporation of a unique cysteine residue and site-specifically conjugated to end-functionalized poly(N-isopropylacrylamide) through thiol-maleimide coupling to form a well-defined model protein-polymer block copolymer. The block copolymer was self-assembled into bulk nanostructures by solvent evaporation from concentrated solutions. Small-angle X-ray scattering and transmission electron microscopy illustrated the formation of highly disordered lamellae or hexagonally perforated lamellae depending upon the selectivity of the solvent during evaporation. Solvent annealing of bulk samples resulted in a transition towards lamellar nanostructures with mCherry packed in a bilayer configuration and a large improvement in long range ordering. Wide-angle X-ray scattering indicated that mCherry did not crystallize within the block copolymer nanodomains and that the ?-sheet spacing was not affected by self-assembly. Circular dichroism showed no change in protein secondary structure after self-assembly, while UV-vis spectroscopy indicated approximately 35% of the chromophore remained optically active. PMID:21696135

Thomas, Carla S.; Glassman, Matthew J.; Olsen, Bradley D.

2014-01-01

37

Three distinct equilibrium states via self-assembly: simple access to a supramolecular ion-controlled NAND logic gate.  

PubMed

During the past several decades, considerable effort has focused on self-assembled systems. However, most work has been directed toward understanding the equilibrium between two major chemical entities, namely the dissociated components and the corresponding associated complex. While there are quite a few examples of 'multiresponsive' materials, control over 'multistate' materials has proved difficult to achieve. Here, we report the formation and the interplay of a self-assembled calix[4]pyrrole array that exhibits three limiting forms, namely a 1:1 self-assembled oligomer, a 2:1 capsule, and the corresponding monomers. Interconversion between these states may be controlled by using the tetraethylammonium cation (TEA(+)) and/or iodide anion (I(-)) as chemical inputs. The combination of self-assembly and ion-based control may be used to create systems that display NAND logic behavior. The system outputs have been confirmed by a variety of analytic methods, including UV-vis and 2D (1)H DOSY, NOESY NMR spectroscopy, scanning electron microscopy, and single crystal X-ray diffraction analyses. PMID:24011216

Kim, Dong Sub; Lynch, Vincent M; Park, Jung Su; Sessler, Jonathan L

2013-10-01

38

Empirical validation of viral quasispecies assembly algorithms: state-of-the-art and challenges  

PubMed Central

Next generation sequencing (NGS) is superseding Sanger technology for analysing intra-host viral populations, in terms of genome length and resolution. We introduce two new empirical validation data sets and test the available viral population assembly software. Two intra-host viral population ‘quasispecies’ samples (type-1 human immunodeficiency and hepatitis C virus) were Sanger-sequenced, and plasmid clone mixtures at controlled proportions were shotgun-sequenced using Roche's 454 sequencing platform. The performance of different assemblers was compared in terms of phylogenetic clustering and recombination with the Sanger clones. Phylogenetic clustering showed that all assemblers captured a proportion of the most divergent lineages, but none were able to provide a high precision/recall tradeoff. Estimated variant frequencies mildly correlated with the original. Given the limitations of currently available algorithms identified by our empirical validation, the development and exploitation of additional data sets is needed, in order to establish an efficient framework for viral population reconstruction using NGS. PMID:24089188

Prosperi, Mattia C. F.; Yin, Li; Nolan, David J.; Lowe, Amanda D.; Goodenow, Maureen M.; Salemi, Marco

2013-01-01

39

Creation of photo-modulated multi-state and multi-scale molecular assemblies via binary-state molecular switch  

E-print Network

to control molecular assembly involves pH,2 light,3 temperature,4 electric,5 redox,6 ultrasound,7 salinity,8 in plants, represent sophisticated biological processes in which optical signals are recorded and transduced as physicochemical events.9 Second, in contrast to redox regent, pH change, salinity and stress, light signal can

Huang, Jianbin

40

Optimized assembly and steady-state length-scale control in dissipative systems of photo-switchable colloids  

NASA Astrophysics Data System (ADS)

Photo-switchable nanoparticles, such as those developed by Wei et al.,footnotetextY.H. Wei, S. B. Han, J. Kim, S. L. Soh and B. A. Grzybowski, J. Am. Chem. Soc., 2010, 132, 11018-11020. can be assembled into a broad range of structures using light exposure as a control parameter. Jha et al.footnotetextP.k. Jha, V. Kuzovkov, B.A. Grzybowski, and M. Olvera del la Cruz, Soft Matter, 2012, 8, 227-234 explored the evolution of these structures using kinetic Monte Carlo simulations. In this work, we build on these studies using Molecular Dynamics with a Langevin thermostat to, by judicious choice of exposure parameters that control the dissipative nature of the system, engineer and optimize the self-assembly pathways as well as control the length scales of the steady-state structures.

Osorio-Vivanco, Antonio; Olvera de La Cruz, Monica; Glotzer, Sharon

2013-03-01

41

Operational planning of electronic assembly systems in the presence of state dependent setup and processing times  

E-print Network

Optimization of the machine and line level issues in an electronic assembly system (EAS) is imperative for the efficient use of resources in the system. This research considers the joint optimization of machine and line level issues in an EAS. Joint...

Subramanian, Gowri Shankar

2012-06-07

42

Conserved and Cooperative Assembly of Membrane-Bound ?-Helical States of Islet Amyloid Polypeptide †  

Microsoft Academic Search

The conversion of soluble protein into ‚-sheet-rich amyloid fibers is the hallmark of a number of serious diseases. Precursors for many of these systems (e.g., A‚ from Alzheimer's disease) reside in close association with a biological membrane. Membrane bilayers are reported to accelerate the rate of amyloid assembly. Furthermore, membrane permeabilization by amyloidogenic peptides can lead to toxicity. Given the

Jefferson D. Knight; James A. Hebda; Andrew D. Miranker

2006-01-01

43

Correction: High-performance all-solid-state flexible micro-supercapacitor arrays with layer-by-layer assembled MWNT/MnOx nanocomposite electrodes.  

PubMed

Correction for 'High-performance all-solid-state flexible micro-supercapacitor arrays with layer-by-layer assembled MWNT/MnOx nanocomposite electrodes' by Geumbee Lee et al., Nanoscale, 2014, 6, 9655-9664. PMID:25365456

Lee, Geumbee; Kim, Daeil; Yun, Junyeong; Ko, Yongmin; Cho, Jinhan; Sook Ha, Jeong

2014-12-21

44

Seal assembly  

DOEpatents

A seal assembly that seals a gap formed by a groove comprises a seal body, a biasing element, and a connection that connects the seal body to the biasing element to form the seal assembly. The seal assembly further comprises a concave-shaped center section and convex-shaped contact portions at each end of the seal body. The biasing element is formed from an elastic material and comprises a convex-shaped center section and concave-shaped biasing zones that are opposed to the convex-shaped contact portions. The biasing element is adapted to be compressed to change a width of the seal assembly from a first width to a second width that is smaller than the first width. In the compressed state, the seal assembly can be disposed in the groove. After release of the compressing force, the seal assembly expands. The contact portions will move toward a surface of the groove and the biasing zones will move into contact with another surface of the groove. The biasing zones will bias the contact portions of the seal body against the surface of the groove.

Johnson, Roger Neal (Hagaman, NY); Longfritz, William David (Fonda, NY)

2001-01-01

45

Modeling capsid kinetics assembly from the steady state distribution of multi-sizes aggregates  

NASA Astrophysics Data System (ADS)

The kinetics of aggregation for particles of various sizes depends on their diffusive arrival and fusion at a specific nucleation site. We present here a mean-field approximation and a stochastic jump model for aggregates at equilibrium. This approach is an alternative to the classical Smoluchowski equations that do not have a close form and are not solvable in general. We analyze these mean-field equations and obtain the kinetics of a cluster formation. Our approach provides a simplified theoretical framework to study the kinetics of viral capsid formation, such as HIV from the self-assembly of the structural proteins Gag.

Hozé, Nathanaël; Holcman, David

2014-01-01

46

An all-atom model of the pore-like structure of hexameric VP40 from Ebola: Structural insights into the monomer–hexamer transition  

Microsoft Academic Search

The matrix protein VP40 is an indispensable component of viral assembly and budding by the Ebola virus. VP40 is a monomer in solution, but can fold into hexameric and octameric states, two oligomeric conformations that play central roles in the Ebola viral life cycle. While the X-ray structures of monomeric and octameric VP40 have been determined, the structure of hexameric

Tam Luong Nguyen; Guy Schoehn; Winfried Weissenhorn; Ann R. Hermone; James C. Burnett; Rekha G. Panchal; Connor McGrath; Dan W. Zaharevitz; M. Javad Aman; Rick Gussio; Sina Bavari

2005-01-01

47

Structure and excited state relaxation dynamics in nanoscale self-assembled arrays: multiporphyrin complexes, porphyrin-quantum dot composites  

NASA Astrophysics Data System (ADS)

Self-assembled nanoscale arrays of controllable geometry and composition (up to 8 tetrapyrroles) have been formed via non-covalent binding interactions of the meso-phenyl bridged Zn-octaethylporphyrin chemical dimers or trimers with di- /tetrapyridyl substituted porphyrin extra-ligands. In these complexes using steady-state and time-resolved (ps fluorescence and fs pump-probe) measurements pathways and efficiencies of the energy transfer photoinduced charge separation as well as exchange d-? effects have been studied in solutions of variable polarity at 77-293 K. The same principles of aggregation via the key-hole scheme "Zn-pyridyl" have been used also for the surface passivation of pyridylsubstituted tetrapyrroles on the coreshell semiconductor CdSe/ZnS quantum dots (QD) showing quantum confinement effects. Picosecond time-resolved and steady-state data reveal that CdSe/ZnS QD emission is multiexponential and the efficiency of its quenching by attached porphyrins (due to energy transfer and photoinduced charge separation) depends strongly on the number of anchoring groups their arrangement in the porphyrin molecule as well as on QD size and number of ZnS monolayers. The analysis of spectroscopic and kinetic findings reveals that on average only ~l/5 porphyrin molecules are assembled on the QD and a limited number of "vacancies" accessible for porphyrin attachment is available on the QD surface.

Zenkevich, E. I.; von Borczyskowski, C.

2005-06-01

48

Zinc chlorins for artificial light-harvesting self-assemble into antiparallel stacks forming a microcrystalline solid-state material  

PubMed Central

We introduce a concept to solve the structure of a microcrystalline material in the solid-state at natural abundance without access to distance constraints, using magic angle spinning (MAS) NMR spectroscopy in conjunction with X-ray powder diffraction and DFT calculations. The method is applied to a novel class of materials that form (semi)conductive 1D wires for supramolecular electronics and artificial light-harvesting. The zinc chlorins 3-devinyl-31-hydroxymethyl-132-demethoxycarbonylpheophorbide a (3?,5?-bis-dodecyloxy)benzyl ester zinc complex 1 and 3-devinyl-31-methoxymethyl-132-demethoxycarbonylpheophorbide a (3?,5?-bis-dodecyloxy)benzyl ester zinc complex 2, self-assemble into extended excitonically coupled chromophore stacks. 1H-13C heteronuclear dipolar correlation MAS NMR experiments provided the 1H resonance assignment of the chlorin rings that allowed accurate probing of ring currents related to the stacking of macrocycles. DFT ring-current shift calculations revealed that both chlorins self-assemble in antiparallel ?-stacks in planar layers in the solid-state. Concomitantly, X-ray powder diffraction measurements for chlorin 2 at 80 °C revealed a 3D lattice for the mesoscale packing that matches molecular mechanics optimized aggregate models. For chlorin 2 the stacks alternate with a periodicity of 0.68 nm and a 3D unit cell with an approximate volume of 6.28 nm3 containing 4 molecules, which is consistent with space group P21221. PMID:19587237

Ganapathy, Swapna; Sengupta, Sanchita; Wawrzyniak, Piotr K.; Huber, Valerie; Buda, Francesco; Baumeister, Ute; Wurthner, Frank; de Groot, Huub J. M.

2009-01-01

49

A Solid-State Compressor for Integration of CO2 Removal and Reduction Assemblies  

NASA Technical Reports Server (NTRS)

Integration of CO2 removal and reduction assemblies in a spacecraft air revitalization system requires an interface with the functionality of a vacuum pump/compressor and a buffer tank. The compressor must meet the vacuum needs of the CO2 removal unit and the pressure needs of the CO2 reduction device, and must also store sufficient CO2 to accommodate the differences in cycle times of the two processes. In this presentation, we describe the design and operation of an adsorption-based device sized for use on the International Space Station. The adsorption compressor functions at a power level approximately ten times lower than a comparable mechanical compression/buffer tank system. The unit is also smaller, lighter, and quieter than its mechanical counterpart.

Mulloth, Lila M.; Finn, John E.; Lung, Bernadette (Technical Monitor)

2000-01-01

50

Shape-persistent macrocyclic aromatic tetrasulfonamides: Molecules with nanosized cavities and their nanotubular assemblies in solid state  

PubMed Central

Alkoxy side-chain-flanked diarylsulfonamide serves as a reliable structural motif for constructing macrocyclic aromatic tetrasulfonamides. This 90° structural motif is persistent both in solution and in the solid state, which allows the one-step formation of tetrasulfonamide macrocycles. These macrocycles adopt a cone-shaped conformation in solution and in the solid state. For each molecule, an interior cavity surrounded by the aromatic residues is formed. The cavity sizes of the macrocycles can be tuned by incorporating aromatic residues of proper sizes. Guest (solvent) molecules are found in the cavities and bound by side chains. In solution, 1H NMR shows that the cone conformations undergo rapid interconversion at room temperature. The alkoxy side chains are found to be indispensable for maintaining the cone conformation. In addition, these porous molecules self-assemble into hollow tubular structures in the solid state. A variety of host molecules and building blocks for constructing nanoporous solid-state structures can be expected from these molecules. PMID:16832059

He, Lan; An, Yu; Yuan, Lihua; Feng, Wen; Li, Minfeng; Zhang, Dechun; Yamato, Kazuhiro; Zheng, Chong; Zeng, Xiao Cheng; Gong, Bing

2006-01-01

51

A unique quinolineboronic acid-based supramolecular structure that relies on double intermolecular B-N bonds for self-assembly in solid state and in solution  

PubMed Central

The boronic acid functional group plays very important roles in sugar recognition, catalysis, organic synthesis, and supramolecular assembly. Therefore, understanding the unique properties of this functional group is very important. 8-Quinolineboronic acid (8-QBA) is found to be capable of self-assembling in solid state through a unique intermolecular B-N bond mechanism reinforced by intermolecular boronic anhydride formation, ?-? stacking, and hydrogen bond formation. NMR NOE and diffusion studies indicate that intermolecular B-N interaction also exists in solution with 8-QBA. In contrast, a positional isomer of 8-QBA, 5-quinolineboronic acid (5-QBA) showed very different behaviors in crystal packing and in solution and therefore different supramolecular network. Understanding the structural features of this unique 8-QBA assembly could be very helpful for the future design of new sugar sensors, molecular catalysts, and supramolecular assemblies. PMID:18414645

Zhang, Yanling; Li, Minyong; Chandrasekaran, Sekar; Gao, Xingming; Fang, Xikui; Lee, Hsiau-Wei; Hardcastle, Kenneth; Yang, Jenny; Wang, Binghe

2007-01-01

52

Resonant Spectroscopy of II-VI Self-Assembled Quantum Dots: Excited States and Exciton-LO Phonon Coupling  

E-print Network

Using resonantly excited photoluminescence along with photoluminescence excitation spectroscopies, we study the carrier excitation processes in CdTe/ZnTe and CdSe/ZnSe self-assembled quantum dots. Photoluminescence excitation spectra of single CdTe quantum dots reflect two major mechanisms for carrier excitation: The first, associated with the presence of sharp and intense lines in the spectrum, is a direct excited state ? ground state transition. The second, associated with the appearance of up to four much broader excitation lines, is a LO phonon-assisted absorption directly into the quantum dot ground states. LO phonons with energies of both quantum dots and ZnTe barrier material are identified in the photoluminescence excitation spectra. Resonantly excited PL measurements for the dot ensemble as a function of excitation energy makes it possible to separate the contributions of these two mechanisms. We find that for CdTe quantum dots the distribution of excited states coupled to the ground states reflects the energy distribution of the quantum dot emission, but shifted up in energy by 100 meV. This large splitting between excited and ground states in CdTe quantum dots suggests strong spatial confinement. In contrast, the LO phonon-assisted absorption shows significant size selectivity. In the case of CdTe dots the exciton-LO phonon coupling is strongly enhanced for smaller-sized dots which have higher emission energies. In contrast, for CdSe quantum dots the exciton-LO phonon coupling is uniform over the ensemble ? that is, the energy distribution determines the intensities of LO phonon replicas. We show that for CdTe quantum dots after annealing, that is after an increase in the average dot size, the exciton-LO phonon interaction reflects the dot energy distribution, as observed for CdSe quantum dots.

T. A. Nguyen; S. Mackowski; H. E. Jackson; L. M. Smith; J. Wrobel; K. Fronc; G. Karczewski; J. Kossut; M. Dobrowolska J. K. Furdyna; W. Heiss

2003-09-17

53

EE101 Labs and ECEbot Assembly/Testing Instructions Montana State University  

E-print Network

revision of our introductory course for freshmen, EE 101: Introduction to Electrical Fundamentals Lab, Montana State University. All Rights Reserved. #12;#12;EE 101 Introduction To Electrical Fundamentals measurement for you. #12;EE 101 Introduction To Electrical Fundamentals, Fall 2008 TABLE I Points of interest

Dyer, Bill

54

Supramolecular assembly of dendritic polymers elucidated by 1H and 13C solid-state MAS NMR spectroscopy.  

PubMed

Advanced solid-state NMR methods under fast magic-angle spinning (MAS) are used to study the structure and dynamics of large supramolecular systems, which consist of a polymer backbone with dendritic side groups and self-assemble into a columnar structure. The NMR experiments are performed on as-synthesized samples, i.e., no isotopic enrichment is required. The analysis of (1)H NMR chemical-shift effects as well as dipolar (1)H-(1)H or (1)H-(13)C couplings provide site-specific insight into the local structure and the segmental dynamics, in particular, of phenyl rings and -CH(2)O- linking units within the dendrons. Relative changes of (1)H chemical shifts (of up to -3 ppm) serve as distance constraints and allow protons to be positioned relative to aromatic rings. Together with dipolar spinning sideband patterns, pi-pi packing phenomena and local order parameters (showing variations between 30% and 100%) are selectively and precisely determined, enabling the identification of the dendron cores as the structure-directing moieties within the supramolecular architecture. The study is carried out over a representative selection of systems which reflect characteristic differences, such as different polymer backbones, sizes of dendritic side groups, or length and flexibility of linking units. While the polymer backbone is found to have virtually no effect on the overall structure and properties, the systems are sensitively affected by changing the generation or the linkage of the dendrons. The results help to understand the self-assembly process of dendritic moieties and aid the chemical design of self-organizing molecular structures. PMID:14570506

Rapp, Almut; Schnell, Ingo; Sebastiani, Daniel; Brown, Steven P; Percec, Virgil; Spiess, Hans Wolfgang

2003-10-29

55

Distance dependence of intrahelix Ru(II)* to Os(II) polypyridyl excited-state energy transfer in oligoproline assemblies.  

PubMed

Energy transfer between the metal-to-ligand charge transfer (MLCT) excited states of [Pra [M(II)(bpy)2(4-Me-4'(-N(H)CO)bpy)](PF6)2 units ([Pra(M(II)bpy2(mbpy)](2+): M(II) = Ru(II) or Os(II), bpy = 2,2'-bipyridine, mbpy = 4'-methyl-2,2'-bipyridine-4-carboxamido, Pra = 4-M(II)-L-proline) linked covalently to oligoproline assemblies in room temperature acetonitrile occurs on the picosecond-nanosecond time scale and has been time-resolved by transient emission measurements. Three derivatized oligoprolines, [CH3-CO-Pro6-Pra[Os(II)(bpy)2(mbpy)](2+)-Pro2-Pra[Ru(II)(bpy)2(mbpy)](2+)-Pro2-Pra[Ru(II)(bpy)2(mbpy)](2+)-Pro6-Glu-NH2](6+) (ORR-2, Pro = L-proline and Glu = glutamic acid); [CH3-CO-Pro6-Pra[Os(II)(bpy)2(mbpy)](2+)-Pro3-Pra[Ru(II)(bpy)2(mbpy)](2+)-Pro3-Pra[Ru(II)(bpy)2(mbpy)](2+)-Pro6-Glu-NH2](6+) (ORR-3); and CH3-CO-Pro6-Pra[Os(II)(bpy)2(mbpy)](2+)-Pro5-Pra[Ru(II)(bpy)2(mbpy)](2+)-Pro5-Pra[Ru(II)(bpy)2(mbpy)](2+)Pro6-Glu2-NH2](6+) (ORR-5), were prepared by using solid-phase peptide synthesis. Given the helical nature of the resulting assemblies and the nature of the synthesis, composition, length, and loading pattern are precisely controlled in the assemblies. In acetonitrile, they adopt a proline I helical secondary structure, confirmed by circular dichroism, in which the appended chromophores are ordered in well-defined orientations and internuclear separation distances although helix formation for ORR-2 is incomplete. Quantitative comparison of oligoproline ground-state absorption and steady-state emission spectra to those for the constituents, [Boc-Pra[M(II)(bpy)2(mbpy)](2+)-OH](PF6)2 (Boc = N(?)-(1,1-dimethylethoxycarbonyl), shows that following Ru(II) light absorption, Ru(II)* undergoes facile energy transfer resulting in sensitization of Os(II). Sensitization efficiencies are 93% for ORR-2, 77% for ORR-3, and 73% for ORR-5. Picosecond-resolved emission measurements reveal complex, coupled dynamics that arise from excited-state decay and kinetically competitive -Ru(II)*-Ru(II)- ? -Ru(II)-Ru(II)*- energy transfer migration/exchange and downhill -Ru(II)*-Os(II) ? -Ru(II)-Os(II)* energy transfer. These processes were modeled simultaneously to extract rate constants for Ru(II)* ? Ru(II) energy-transfer migration, k(Ru*-Ru), and Ru(II)* ? Os(II) energy transfer, k(Ru*-Os). For ORR-2, k(Ru*-Ru) = 2.9 × 10(7) s(-1) and k(Ru*-Os) = 3.4 × 10(8) s(-1). For ORR-3, k(Ru*-Ru) = 1.2 × 10(7) s(-1) and k(Ru*-Os) = 1.3 × 10(8) s(-1). For ORR-5, k(Ru*-Ru) = 3.6 × 10(6) s(-1) and k(Ru*-Os) = 5.8 × 10(7) s(-1), all in acetonitrile at 22 °C. The data were analyzed by assuming Dexter energy transfer with the Franck-Condon factors arising from intramolecular structural and medium changes evaluated by use of an emission spectral fitting procedure. Fits of the data to the Dexter mechanism were consistent with the predicted distance dependence of energy transfer. PMID:23634850

Brennaman, M Kyle; Fleming, Cavan N; Slate, Cheryl A; Serron, Scafford A; Bettis, Stephanie E; Erickson, Bruce W; Papanikolas, John M; Meyer, Thomas J

2013-05-30

56

EXTENSION ADMINISTRATION AND STATE LEGISLATIVE PROCESS--A CASE STUDY OF THE 71ST MISSOURI GENERAL ASSEMBLY.  

ERIC Educational Resources Information Center

TO GAIN UNDERSTANDING OF MISSOURI'S LEGISLATIVE PROCESS AND AID ADMINISTRATORS OF THE EXTENSION DIVISION, THE AUTHOR INVESTIGATED THE 71ST GENERAL ASSEMBLY. HE READ PUBLICATIONS, INTERVIEWED LOBBYISTS, AND CONDUCTED OPEN ENDED DEPTH INTERVIEWS WITH LEGISLATORS SELECTED TO COMPRISE THE LEADERSHIP OF THE ASSEMBLY. HIS DISSERTATION PRESENTS THE…

KYD, STIRLING

57

Measuring deuteron beam parameters with solid-state track detectors in experiments with the QUINTA target assembly  

NASA Astrophysics Data System (ADS)

The results of measurements of the beam parameters on the target upon irradiation of the QUINTA subcritical uranium assembly with deuterons with energies of 1, 4, and 8 GeV are presented. Data on the position of the incident particle beam relative to the assembly axis and on the actual geometric parameters of the beam make it possible to analyze information on the spatial distributions of reaction rates within the target assembly correctly, comparing such distributions obtained at different irradiation sessions and modeling the experiments with the use of MCNPX, GEANT4, FLUKA, and other similar software tools.

Artyushenko, M. Yu.; Voronko, V. A.; Gusak, K. V.; Zhuk, I. V.; Kadykov, M. G.; Potapenko, A. S.; Safronova, A. A.; Sotnikov, V. V.; Tyutyunnikov, S. I.; Furman, V. I.; Chilap, V. V.; Chinenov, A. V.

2013-11-01

58

Investigation of structure and chemical states of self-assembled Au nanoscale particles by angle-resolved X-ray photoelectron spectroscopy  

NASA Astrophysics Data System (ADS)

The surface structure of the silane self-assembled monolayer (SAM) prepared by 3-mercaptopropyl-trimethyl-silane (MPTMS) on Si(111) and the chemical states of the self-assembled Au nanoparticles absorbed onto the surface of the silane SAM were studied by angle-resolved X-ray photoelectron spectroscopy. The thickness of the silane SAM was determined as the vertical distance between sulfur atoms on the surface of the silane SAM and the surface of the SiO 2 overlayer on the silicon substrate, and had a value of 4.7 Å. In addition, two types of sulfur species were detected in the self-assembled Au nanoparticles at an electron take-off angle of 5°. These species are assigned as bound thiolate and unbound thiol with S 2p binding energies of 162.6 eV and 164.6 eV respectively. The assignments indicate that the gold-thiolate bond was formed when Au nanoparticles were assembled onto the surface of the silicon substrate through MPTMS as a coupling agent.

Huang, Xiaohua; Huang, Huizhong; Wu, Nianzu; Hu, Ruisheng; Zhu, Tao; Liu, Zhongfan

2000-07-01

59

Kinetic intermediates in amyloid assembly.  

PubMed

In contrast to an expected Ostwald-like ripening of amyloid assemblies, the nucleating core of the Dutch mutant of the A? peptide of Alzheimer's disease assembles through a series of conformational transitions. Structural characterization of the intermediate assemblies by isotope-edited IR and solid-state NMR reveals unexpected strand orientation intermediates and suggests new nucleation mechanisms in a progressive assembly pathway. PMID:25313920

Liang, Chen; Ni, Rong; Smith, Jillian E; Childers, W Seth; Mehta, Anil K; Lynn, David G

2014-10-29

60

Silencing and Languaging in the Assembling of the Indian Nation-State: British Public Citizens, the Epistolary Form, and Historiography  

ERIC Educational Resources Information Center

Taking the case of postcolonial India, this paper explores ways in which present temporal junctures permit a probing of historical boundaries to speak of voices largely silenced from Indian historiography, namely those of British (Indian) public citizens who were committed to the assembling of "an India." In particular, the paper discusses ways in…

Ramanathan, Vaidehi

2009-01-01

61

Photoinduced radical generation and self-assembly of tetrathiafulvalene into the mixed-valence state in the poly(vinyl chloride) film under UV irradiation.  

PubMed

The photoinduced self-assembly and the formation of the mixed-valence state of tetrathiafulvalene (TTF) in the solid state are reported. The polymer composites containing TTF in poly(vinyl chloride) (PVC) were prepared, and oxidation of TTF by chlorine radical generated by UV irradiation in PVC was investigated. The formation of the mixed-valence state of TTF in the composite films by UV irradiation was observed, and the resulting TTF radical species, including the mixed-valence state after the photopatterning, exhibited extremely high stability in the composite films. Finally, we performed the fabrication of the gradient materials of the radical concentrations on the TTF/PVC composites with the photopatterning. PMID:20067314

Tanaka, Kazuo; Ishiguro, Fumiyasu; Chujo, Yoshiki

2010-01-19

62

Peroxisomal Targeting, Import, and Assembly of Alcohol Oxidase in Pichia pastoris  

PubMed Central

Alcohol oxidase (AOX), the first enzyme in the yeast methanol utilization pathway is a homooctameric peroxisomal matrix protein. In peroxisome biogenesis-defective (pex) mutants of the yeast Pichia pastoris, AOX fails to assemble into active octamers and instead forms inactive cytoplasmic aggregates. The apparent inability of AOX to assemble in the cytoplasm contrasts with other peroxisomal proteins that are able to oligomerize before import. To further investigate the import of AOX, we first identified its peroxisomal targeting signal (PTS). We found that sequences essential for targeting AOX are primarily located within the four COOH-terminal amino acids of the protein leucine-alanine-arginine-phenylalanine COOH (LARF). To examine whether AOX can oligomerize before import, we coexpressed AOX without its PTS along with wild-type AOX and determined whether the mutant AOX could be coimported into peroxisomes. To identify the mutant form of AOX, the COOH-terminal LARF sequence of the protein was replaced with a hemagglutinin epitope tag (AOX–HA). Coexpression of AOX–HA with wild-type AOX (AOX-WT) did not result in an increase in the proportion of AOX–HA present in octameric active AOX, suggesting that newly synthesized AOX–HA cannot oligomerize with AOX-WT in the cytoplasm. Thus, AOX cannot initiate oligomerization in the cytoplasm, but must first be targeted to the organelle before assembly begins. PMID:9396748

Waterham, Hans R.; Russell, Kimberly A.; Vries, Yne de; Cregg, James M.

1997-01-01

63

Engineering solid-state materials. Strategies for modeling and packing control of molecular assemblies into 3-D networks  

NASA Astrophysics Data System (ADS)

The crystal structure and properties of a number of urea cocrystals are studied with regard to symmetry of the hydrogen-bonded molecular assemblies. The logical consequences of hydrogen bonding interactions are followed step-by-step. The problems of aggregate formation, nucleation, and crystal growth are also elucidated. Endeavor is made to envisage the 2-D and 3-D hydrogen bond network in a manageable way by exploiting graph set short hand. Strategies of how to control the symmetry of molecular packing are still to be elaborated. In our strategy, the programmed self-assembly has been based on the principle of molecular recognition of self- and hetero-complementary functional groups. However, the main focus for pre-organizational control has been put on the two-fold axis estimator of the urea molecule.

Videnova-Adrabinska, V.; Etter, M. C.; Ward, M. D.

1993-04-01

64

NMR relaxation studies of an RNA-binding segment of the Rous sarcoma virus Gag polyprotein in free and bound states - a model for autoinhibition of assembly  

PubMed Central

Assembly of retrovirus particles is promoted by interaction of the Gag polyprotein with RNA. Nonspecific RNA association with the nucleocapsid domain (NC) of Gag induces the dimerization of Gag through protein-protein contacts in the capsid domain (CA), followed by higher-order assembly to form the immature virus particle. NMR relaxation studies were conducted to investigate the initial steps of Rous sarcoma virus (RSV) assembly by examining the association with nucleic acid of a fragment of Gag comprising the C-terminal domain of CA (CTD) postulated to mediate Gag dimerization, the spacer region between CA and NC (SP), and NC. This fragment, CTD-SP-NC (residues 394 to 577), spans the critical SP region and allows assessment of this key Gag-nucleic acid interaction in the context of the Gag polyprotein rather than the isolated domains. Mainchain amide relaxation of CTD-SP-NC was measured in the absence and presence of (GT)4, an 8-mer DNA oligonucleotide that binds tightly to the polyprotein but is too short to promote Gag dimerization. The results show that the CTD and NC domains tumble independently. In contrast, the two zinc finger domains within NC are rotationally coupled in both the unbound and bound states, even though only the first zinc finger appears to make direct contact with (GT)4. In addition, the NMR data indicate that SP and flanking residues undergo a conformational exchange process that is slowed in the presence of (GT)4. This region around SP where relaxation is strongly affected by (GT)4 binding is nearly identical to the assembly domain defined previously by mutagenesis studies. Other changes in relaxation induced by (GT)4 implicate conformational perturbations of helices 1 and 4 in CTD. Based on the combined data, we propose a model for the promotion of Gag dimerization by RNA association in which NC-RNA binding disrupts an assembly-inhibitory, intramolecular interaction involving SP and CTD. Disruption of this intramolecular interaction is proposed to enhance the accessibility of the Gag dimer contact surface and release the assembly domain to promote intermolecular oligomerization. PMID:20387899

Taylor, Gwen M.; Ma, Lixin; Vogt, Volker M.; Post, Carol Beth

2010-01-01

65

In-situ x-ray scattering study of continuous silica-surfactant self-assembly during steady-state dip coating.  

SciTech Connect

Inorganic mesoporous thin-films are import for applications such as membranes, sensors, low-dielectric-constant insulators (so-called low {kappa} dielectrics), and fluidic devices. Over the past five years, several research groups have demonstrated the efficacy of using evaporation accompanying conventional coating operations such as spin- and dip-coating as an efficient means of driving the self-assembly of homogeneous solutions into highly ordered, oriented, mesostructured films. Understanding such evaporation-induced self-assembly (EISA) processes is of interest for both fundamental and technological reasons. Here, the authors use spatially resolved 2D grazing incidence X-ray scattering in combination with optical interferometry during steady-state dip-coating of surfactant-templated silica thin-films to structurally and compositionally characterize the EISA process. They report the evolution of a hexagonal (p6 mm) thin-film mesophase from a homogeneous precursor solution and its further structural development during drying and calcination. Monte Carlo simulations of water/ethanol/surfactant bulk phase behavior are used to investigate the role of ethanol in the self-assembly process, and they propose a mechanism to explain the observed dilation in unit cell dimensions during solvent evaporation.

Hurd, Alan J.; Gibaud, Alain; Brinker, C. Jeffrey; Dunphy, Darren Robert; van Swol, Frank B.; Wang, Jin (Argonne National Laboratory, Argonne, IL); MacPhee, Andrew (Argonne National Laboratory, Argonne, IL); Malanoski, Anthony P. (University of New Mexico, Albuquerque, NM); Narayanan, Suresh (Argonne National Laboratory, Argonne, IL); Doshi, Dhaval A. (University of New Mexico, Albuquerque, NM); Chen, Hongji (University of New Mexico, Albuquerque, NM); Liu, Nanguo (University of New Mexico, Albuquerque, NM); Reed, Scott T.; Sturmayr, Dietmar (Vienna University of Technology, Vienna, Austria)

2002-06-01

66

Conformational transitions in human translin enable nucleic acid binding  

PubMed Central

Translin is a highly conserved RNA- and DNA-binding protein that plays essential roles in eukaryotic cells. Human translin functions as an octamer, but in the octameric crystallographic structure, the residues responsible for nucleic acid binding are not accessible. Moreover, electron microscopy data reveal very different octameric configurations. Consequently, the functional assembly and the mechanism of nucleic acid binding by the protein remain unclear. Here, we present an integrative study combining small-angle X-ray scattering (SAXS), site-directed mutagenesis, biochemical analysis and computational techniques to address these questions. Our data indicate a significant conformational heterogeneity for translin in solution, formed by a lesser-populated compact octameric state resembling the previously solved X-ray structure, and a highly populated open octameric state that had not been previously identified. On the other hand, our SAXS data and computational analyses of translin in complex with the RNA oligonucleotide (GU)12 show that the internal cavity found in the octameric assemblies can accommodate different nucleic acid conformations. According to this model, the nucleic acid binding residues become accessible for binding, which facilitates the entrance of the nucleic acids into the cavity. Our data thus provide a structural basis for the functions that translin performs in RNA metabolism and transport. PMID:23980029

Perez-Cano, Laura; Eliahoo, Elad; Lasker, Keren; Wolfson, Haim J.; Glaser, Fabian; Manor, Haim; Bernado, Pau; Fernandez-Recio, Juan

2013-01-01

67

Excited electron dynamics at ferrocene-terminated self-assembled monolayers on Au(1 1 1): Lengthened lifetime of image potential state  

NASA Astrophysics Data System (ADS)

Ultraviolet photoemission spectroscopy (UPS) and two-photon photoemission (2PPE) spectroscopy have been employed to investigate the electronic states and the excited electron dynamics of ferrocene (Fc)-terminated self-assembled monolayers (SAMs) on Au(1 1 1). For the 11-ferrocenyl-1-undecanethiol (FcC11-) SAM, an image potential state (IPS) located at EF +3.8 eV was observed by time-resolved 2PPE. Its lifetime, 90 fs, was found to be much shorter than that of decanethiol (C10-) SAM, 11 ps. By forming the C10-SAM beforehand, the IPS lifetime for FcC11-&C10-SAM was lengthened to ˜9 ps; this can enable improvement in molecular ordering and substantial formation of C10 domains.

Hirata, Naoyuki; Shibuta, Masahiro; Eguchi, Toyoaki; Nakajima, Atsushi

2013-03-01

68

Assembly of NADPH oxidase in human neutrophils is modulated by the opacity-associated protein expression State of Neisseria gonorrhoeae.  

PubMed

Neisseria gonorrhoeae (the gonococcus, Gc) triggers a potent inflammatory response and recruitment of neutrophils to the site of infection. Gc survives exposure to neutrophils despite these cells' antimicrobial products, such as reactive oxygen species (ROS). ROS production in neutrophils is initiated by NADPH oxidase, which converts oxygen into superoxide. The subunits of NADPH oxidase are spatially separated between granules (gp91(phox)/p22(phox)) and the cytoplasm (p47(phox), p67(phox), and p40(phox)). Activation of neutrophils promotes the coassembly of NADPH oxidase subunits at phagosome and/or plasma membranes. While Gc-expressing opacity-associated (Opa) proteins can induce neutrophils to produce ROS, Opa-negative (Opa-) Gc does not stimulate neutrophil ROS production. Using constitutively Opa- and OpaD-positive (OpaD+) Gc bacteria in strain FA1090, we now show that the difference in ROS production levels in primary human neutrophils between these backgrounds can be attributed to differential assembly of NADPH oxidase. Neutrophils infected with Opa- Gc showed limited translocation of NADPH oxidase cytoplasmic subunits to cellular membranes, including the bacterial phagosome. In contrast, these subunits rapidly translocated to neutrophil membranes following infection with OpaD+ Gc. gp91(phox) and p22(phox) were recruited to Gc phagosomes regardless of bacterial Opa expression. These results suggest that Opa- Gc interferes with the recruitment of neutrophil NADPH oxidase cytoplasmic subunits to membranes, in particular, the p47(phox) "organizing" subunit, to prevent assembly of the holoenzyme, resulting in an absence of the oxidative burst. PMID:24343654

Smirnov, Asya; Daily, Kylene P; Criss, Alison K

2014-03-01

69

Well-defined excited states of self-assembled InAs/InAlGaAs quantum dots on InP (001)  

SciTech Connect

Self-assembled InAs/InAlGaAs quantum dots (QDs) in an InAlGaAs matrix on InP (001) substrates were grown by the alternate growth method (AGQD), where an InAs layer with a thickness of 1 monolayer (ML) and an InAlGaAs layer with a thickness of 1 ML were alternately deposited. Cross-sectional transmission electron microscopy images indicated that the aspect ratio (height/width) for the AGQDs was {approx}0.25, which was higher than {approx}0.10 of conventionally grown InAs QDs. The photoluminescence (PL) peak position for the ground states of the AGQDs was 1.485 {mu}m with a linewidth broadening of 42 meV at room temperature, while the PL linewidth for the conventionally grown QDs was 85 meV. And the peaks for the excited-state transitions were also clearly observed from the excitation-power dependent PL. This is the first observation on the well-defined excited-state transitions from the InP-based InAs QDs, even though there were several reports on the features of the excited states.

Kim, Jin Soo; Lee, Jin Hong; Hong, Sung Ui; Kwack, Ho-Sang; Choi, Byung Seok; Oh, Dae Kon [Basic Research Laboratory, Electronics and Telecommunications Research Institute (ETRI), Daejeon (Korea, Republic of)

2005-08-01

70

Solid-state densification of spun-cast self-assembled monolayers for use in ultra-thin hybrid dielectrics  

NASA Astrophysics Data System (ADS)

Ultra-thin self-assembled monolayer (SAM)-oxide hybrid dielectrics have gained significant interest for their application in low-voltage organic thin film transistors (OTFTs). A [8-(11-phenoxy-undecyloxy)-octyl]phosphonic acid (PhO-19-PA) SAM on ultrathin AlOx (2.5 nm) has been developed to significantly enhance the dielectric performance of inorganic oxides through reduction of leakage current while maintaining similar capacitance to the underlying oxide structure. Rapid processing of this SAM in ambient conditions is achieved by spin coating, however, as-cast monolayer density is not sufficient for dielectric applications. Thermal annealing of a bulk spun-cast PhO-19-PA molecular film is explored as a mechanism for SAM densification. SAM density, or surface coverage, and order are examined as a function of annealing temperature. These SAM characteristics are probed through atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and near edge X-ray absorption fine structure spectroscopy (NEXAFS). It is found that at temperatures sufficient to melt the as-cast bulk molecular film, SAM densification is achieved; leading to a rapid processing technique for high performance SAM-oxide hybrid dielectric systems utilizing a single wet processing step. To demonstrate low-voltage devices based on this hybrid dielectric (with leakage current density of 7.7 × 10-8 A cm-2 and capacitance density of 0.62 ?F cm-2 at 3 V), pentacene thin-film transistors (OTFTs) are fabricated and yield sub 2 V operation and charge carrier mobilites of up to 1.1 cm2 V-1 s-1.

Hutchins, Daniel O.; Acton, Orb; Weidner, Tobias; Cernetic, Nathan; Baio, Joe E.; Castner, David G.; Ma, Hong; Jen, Alex K.-Y.

2012-11-01

71

Electron transfer dynamics and excited state branching in a charge-transfer platinum(ii) donor-bridge-acceptor assembly.  

PubMed

A linear asymmetric Pt(ii) trans-acetylide donor-bridge-acceptor triad designed for efficient charge separation, NAP[triple bond, length as m-dash]Pt(PBu3)2[triple bond, length as m-dash]Ph-CH2-PTZ (), containing strong electron acceptor and donor groups, 4-ethynyl-N-octyl-1,8-naphthalimide (NAP) and phenothiazine (PTZ) respectively, has been synthesised and its photoinduced charge transfer processes characterised in detail. Excitation with 400 nm, ?50 fs laser pulse initially populates a charge transfer manifold stemming from electron transfer from the Pt-acetylide centre to the NAP acceptor and triggers a cascade of charge and energy transfer events. A combination of ultrafast time-resolved infrared (TRIR) and transient absorption (TA) spectroscopies, supported by UV-Vis/IR spectroelectrochemistry, emission spectroscopy and DFT calculations reveals a self-consistent photophysical picture of the excited state evolution from femto- to milliseconds. The characteristic features of the NAP-anion and PTZ-cation are clearly observed in both the TRIR and TA spectra, confirming the occurrence of electron transfer and allowing the rate constants of individual ET-steps to be obtained. Intriguingly, has three separate ultrafast electron transfer pathways from a non-thermalised charge transfer manifold directly observed by TRIR on timescales ranging from 0.2 to 14 ps: charge recombination to form either the intraligand triplet (3)NAP with 57% yield, or the ground state, and forward electron transfer to form the full charge-separated state (3)CSS ((3)[PTZ(+)-NAP(-)]) with 10% yield as determined by target analysis. The (3)CSS decays by charge-recombination to the ground state with ?1 ns lifetime. The lowest excited state is (3)NAP, which possesses a long lifetime of 190 ?s and efficiently sensitises singlet oxygen. Overall, molecular donor-bridge-acceptor triad demonstrates excited state branching over 3 different pathways, including formation of a long-distant (18 Å) full charge-separated excited state from a directly observed vibrationally hot precursor state. PMID:25361227

Scattergood, Paul A; Delor, Milan; Sazanovich, Igor V; Bouganov, Oleg V; Tikhomirov, Sergei A; Stasheuski, Alexander S; Parker, Anthony W; Greetham, Gregory M; Towrie, Michael; Davies, E Stephen; Meijer, Anthony J H M; Weinstein, Julia A

2014-11-12

72

Hinge assembly  

DOEpatents

A hinge assembly is disclosed having a first leaf, a second leaf and linking member. The first leaf has a contact surface. The second leaf has a first contact surface and a second contact surface. The linking member pivotally connects to the first leaf and to the second leaf. The hinge assembly is capable of moving from a closed position to an open position. In the closed position, the contact surface of the first leaf merges with the first contact surface of the second leaf. In the open position, the contact surface of the first leaf merges with the second contact surface of the second leaf. The hinge assembly can include a seal on the contact surface of the first leaf. 8 figs.

Vandergriff, D.H.

1999-08-31

73

Reprint of: Out-of-equilibrium dynamics in superspin glass state of strongly interacting magnetic nanoparticle assemblies  

NASA Astrophysics Data System (ADS)

Interacting magnetic nanoparticles display a wide variety of magnetic behaviors ranging from modified superparamagnetism, superspin glass to possibly, superferromagnetism. The superspin glass state is described by its slow and out-of-equilibrium magnetic behaviors akin to those found in atomic spin glasses. In this article, recent experimental findings on superspin correlation length growth and the violation of the fluctuation-dissipation theorem obtained in concentrated frozen ferrofluids are presented to illustrate certain out-of-equilibrium dynamics behavior in superspin glasses.

Nakamae, Sawako

2014-11-01

74

Latch assembly  

DOEpatents

A latch assembly for releasably securing an article in the form of a canister within a container housing. The assembly includes a cam pivotally mounted on the housing wall and biased into the housing interior. The cam is urged into a disabled position by the canister as it enters the housing and a latch release plate maintains the cam disabled when the canister is properly seated in the housing. Upon displacement of the release plate, the cam snaps into latching engagement against the canister for securing the same within the housing. 2 figs.

Frederickson, J.R.; Harper, W.H.; Perez, R.

1984-08-17

75

Latch assembly  

DOEpatents

A latch assembly for releasably securing an article in the form of a canister within a container housing. The assembly includes a cam pivotally mounted on the housing wall and biased into the housing interior. The cam is urged into a disabled position by the canister as it enters the housing and a latch release plate maintains the cam disabled when the canister is properly seated in the housing. Upon displacement of the release plate, the cam snaps into latching engagement against the canister for securing the same within the housing.

Frederickson, James R. (Richland, WA); Harper, William H. (Richland, WA); Perez, Raymond (Lynnwood, WA)

1986-01-01

76

Phosphorylation of a p38-like MAPK is involved in sensing cellular redox state and drives atypical tubulin polymer assembly in angiosperms.  

PubMed

Reactive oxygen species (ROS) imbalance is a stressful condition for plant cells accompanied by dramatic changes in tubulin cytoskeleton. Here, evidence is provided that alterations in ROS levels directly interfere with the phosphorylation state of a p38-like MAPK in the angiosperms Triticum turgidum and Arabidopsis thaliana. Both oxidative stress generators and chemicals inducing ROS scavenging or decreasing ROS production resulted in the accumulation of a phospho-p46 protein similar to p38-MAPK. Importantly, the rhd2 A.?thaliana mutants exhibited a remarkable increase in levels of phospho-p46. The presence of the p38-MAPK inhibitor SB203580 attenuated the response to ROS disturbance, prevented microtubule disappearance and resulted in a dramatic decrease in the number of atypical tubulin polymers. Moreover, in roots treated simultaneously with substances inducing ROS overproduction and others resulting in low ROS levels, phospho-p46 levels and the organization of tubulin cytoskeleton were similar to controls. Collectively, our experimental data suggest, for the first time in plants, that p46 functions as a putative sensor of redox state, the activation of which initiates downstream signalling events leading to microtubule disruption and subsequent assembly of atypical tubulin polymers. Thus, p46 seems to participate in perception of ROS homeostasis disturbance as well as in cellular responses to redox imbalance. PMID:24138172

Livanos, Pantelis; Galatis, Basil; Gaitanaki, Catherine; Apostolakos, Panagiotis

2014-05-01

77

Furnace assembly  

DOEpatents

A method of and apparatus for heating test specimens to desired elevated temperatures for irradiation by a high energy neutron source. A furnace assembly is provided for heating two separate groups of specimens to substantially different, elevated, isothermal temperatures in a high vacuum environment while positioning the two specimen groups symmetrically at equivalent neutron irradiating positions.

Panayotou, Nicholas F. (Kennewick, WA); Green, Donald R. (Richland, WA); Price, Larry S. (Pittsburg, CA)

1985-01-01

78

Elements That Should Be Contained in an Omnibus Public Employees' Collective Bargaining Act: Using House Bill 808 and House Bill 1178--Introduced into the 81st General Assembly of the State of Illinois. [An Overview of Collective Bargaining, Part 3].  

ERIC Educational Resources Information Center

Two bills considered by the 81st General Assembly of the State of Illinois could provide access to collective bargaining for public employees. House Bill 808 provides these rights to employees in public and higher education, and House Bill 1178 requires collective bargaining for police officers in units of local government with populations under…

Larson, T.

79

Redox state of pentraxin 3 as a novel biomarker for resolution of inflammation and survival in sepsis.  

PubMed

In an endotoxaemic mouse model of sepsis, a tissue-based proteomics approach for biomarker discovery identified long pentraxin 3 (PTX3) as the lead candidate for inflamed myocardium. When the redox-sensitive oligomerization state of PTX3 was further investigated, PTX3 accumulated as an octamer as a result of disulfide-bond formation in heart, kidney, and lung-common organ dysfunctions seen in patients with sepsis. Oligomeric moieties of PTX3 were also detectable in circulation. The oligomerization state of PTX3 was quantified over the first 11 days in critically ill adult patients with sepsis. On admission day, there was no difference in the oligomerization state of PTX3 between survivors and non-survivors. From day 2 onward, the conversion of octameric to monomeric PTX3 was consistently associated with a greater survival after 28 days of follow-up. For example, by day 2 post-admission, octameric PTX3 was barely detectable in survivors, but it still constituted more than half of the total PTX3 in non-survivors (p < 0.001). Monomeric PTX3 was inversely associated with cardiac damage markers NT-proBNP and high-sensitivity troponin I and T. Relative to the conventional measurements of total PTX3 or NT-proBNP, the oligomerization of PTX3 was a superior predictor of disease outcome. PMID:24958171

Cuello, Friederike; Shankar-Hari, Manu; Mayr, Ursula; Yin, Xiaoke; Marshall, Melanie; Suna, Gonca; Willeit, Peter; Langley, Sarah R; Jayawardhana, Tamani; Zeller, Tanja; Terblanche, Marius; Shah, Ajay M; Mayr, Manuel

2014-10-01

80

Axial chiral bisbenzophenazines: solid-state self-assembly via halide hydrogen bonds triggered by linear alkanes.  

PubMed

An axial chiral tetrachlorinated bisbenzo[a]phenazine has been discovered that undergoes an alkane-induced shift in the solid state from a disordered amorphous form to an ordered polycrystalline form. This phase transition is caused by the formation of pores that accommodate linear alkanes of varying lengths with a very strong affinity as judged by differential scanning calorimetry. Single crystal X-ray structure analysis revealed that a series of weak phenolic OH···Cl hydrogen bonds dictates the pore structure. These weak interactions can be disrupted mechanically, causing the material to revert to the amorphous form. Notably, the interchange between the amorphous and crystalline forms is readily reversible and is easily observed by characteristic colorimetric changes. Measurements via photoimage processing reveal that the degree of color change is dictated by the type of alkane employed. PMID:25019179

Metz, Alison E; Podlesny, Erin E; Carroll, Patrick J; Klinghoffer, Ariel N; Kozlowski, Marisa C

2014-07-30

81

Beginning Assembly  

Microsoft Academic Search

\\u000a Now it’s time to see the efforts of your labor take shape, literally. In this and the next three chapters, we’ll walk you\\u000a through the process of assembling the basic framework of the 3D printer. The electronics (including the motors) will come\\u000a later, but for now you’ll need to grab some basic tools such as Philips and slot screwdrivers (electric\\/portable

Patrick Hood-Daniel; James Floyd Kelly

82

Seal assembly  

SciTech Connect

A seal assembly comprises a tube rotatable about its longitudinal axis and having two longitudinally spaced flanges projecting radially outwardly from the outer surface thereof. Slidably positioned against one of the flanges is a seal ring, and disposed between this seal ring and the other flange are two rings that are forced apart by springs, one of the latter rings being attached to a flexible wall.

Morgan, J.G.; Rennich, M.J.; Whatley, M.E.

1981-03-13

83

Pushrod assembly  

DOEpatents

A pushrod assembly including a carriage mounted on a shaft for movement therealong and carrying a pushrod engageable with a load to be moved is described. A magnet is mounted on a supporting bracket for movement along such shaft. Means are provided for adjustably spacing magnet away from the carriage to obtain a selected magnetic attractive or coupling force therebetween. Movement of the supporting bracket and the magnet carried thereby pulls the carriage along with it until the selected magnetic force is exceeded by a resistance load acting on the carriage.

Potter, J.D.

1984-03-30

84

Pushrod assembly  

DOEpatents

A pushrod assembly including a carriage mounted on a shaft for movement therealong and carrying a pushrod engageable with a load to be moved. A magnet is mounted on a supporting bracket for movement along such shaft. Means are provided for adjustably spacing said magnet away from said carriage to obtain a selected magnetic attractive or coupling force therebetween. Movement of the supporting bracket and the magnet carried thereby pulls the carriage along with it until the selected magnetic force is exceeded by a resistance load acting on the carriage.

Potter, Jerry D. (Kennewick, WA)

1987-01-01

85

DETERRENCE AND THE DEATH PENALTY: A CRITICAL REVIEW OF NEW EVIDENCE Testimony to the New York State Assembly Standing Committee on Codes, Assembly Standing Committee on Judiciary and Assembly Standing Committee on Correction Hearings on the Future of Capital Punishment in the State of New York  

Microsoft Academic Search

Thank you for inviting me to address the Committees on this most urgent of topics. This is an important moment historically in the debate on capital punishment, both in the state and the nation. This moment presents opportunity for the citizens of New York State to carefully consider this most serious exercise of the state's authority and power.

Jeffrey Fagan

86

Los Alamos Critical Assemblies Facility  

SciTech Connect

The Critical Assemblies Facility of the Los Alamos National Laboratory has been in existence for thirty-five years. In that period, many thousands of measurements have been made on assemblies of /sup 235/U, /sup 233/U, and /sup 239/Pu in various configurations, including the nitrate, sulfate, fluoride, carbide, and oxide chemical compositions and the solid, liquid, and gaseous states. The present complex of eleven operating machines is described, and typical applications are presented.

Malenfant, R.E.

1981-06-01

87

Thermocouple assembly  

DOEpatents

A thermocouple assembly includes a thermocouple; a plurality of lead wires extending from the thermocouple; an insulating jacket extending along and enclosing the plurality of leads; and at least one internally sealed area within the insulating jacket to prevent fluid leakage along and within the insulating jacket. The invention also provides a method of preventing leakage of a fluid along and through an insulating jacket of a thermocouple including the steps of a) attaching a plurality of lead wires to a thermocouple; b) adding a heat sensitive pseudo-wire to extend along the plurality of lead wires; c) enclosing the lead wires and pseudo-wire inside an insulating jacket; d) locally heating axially spaced portions of the insulating jacket to a temperature which melts the pseudo-wire and fuses it with an interior surface of the jacket.

Thermos, Anthony Constantine (Greer, SC); Rahal, Fadi Elias (Easley, SC)

2002-01-01

88

Micromanifold assembly  

DOEpatents

A micromanifold for connecting external capillaries to the inlet and/or outlet ports of a microfluidic device can employ a ferrule/capillary assembly that includes: (a) a ferrule comprising an elongated member and having a bore traversing from a proximal end to a distal end of the member, wherein the bore has an inner surface and wherein the distal end of the ferrule has a tapered, threaded exterior surface, and (b) a capillary that is positioned within the bore wherein the capillary's outer surface is in direct contact with the bore's inner surface. No mating sleeve is required for the one-piece ferrule. Alternatively, the capillaries can be bonded to channels that traverse the manifold and therefore obviate the need for a ferrule.

Renzi, Ronald F. (Tracey, CA); Ferko, Scott (Livermore, CA)

2009-06-30

89

IAHS Third Scientific Assembly  

NASA Astrophysics Data System (ADS)

The International Association of Hydrological Sciences (IAHS) convened its Third Scientific Assembly in Baltimore, Md., May 10-19, 1989. The Assembly was attended by about 450 scientists and engineers. The attendance was highest from the U.S., as could be expected; 37 were from Canada; 22 each, Netherlands and United Kingdom; 14, Italy; 12, China; 10, Federal Republic of Germany; 8 each from France, the Republic of South Africa, and Switzerland; 7, Austria; 6 each, Finland and Japan; others were scattered among the remainder of 48 countries total.one of the cosponsors and also handled business matters for the Assembly. Other cosponsors included the International Association of Meteorology and Atmospheric Physics (IAMAP), United Nations Environmental Program (UNEP), United Nations Educational, Scientific, and Cultural Organization (UNESCO), World Meteorological Organization (WMO), and U.K. Overseas Development Authority (ODA). U.S. federal agencies serving as cosponsors included the Environmental Protection Agency, National Aeronautics and Space Administration, National Science Foundation, National Weather Service, Department of Agriculture, Department of State, and U.S. Geological Survey.

90

Rubisco Accumulation Factor 1 from Thermosynechococcus elongatus participates in the final stages of ribulose-1,5-bisphosphate carboxylase/oxygenase assembly in Escherichia coli cells and in vitro.  

PubMed

Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) biosynthesis is a multi-step process in which specific chaperones are involved. Recently, a novel polypeptide, Rubisco Accumulation Factor 1 (RAF1), has been identified as a protein that is necessary for proper assembly of this enzyme in maize cells (Zea mays). However, neither its specific function nor its mode of action have as yet been determined. The results presented here show that the prokaryotic homolog of RAF1 from Thermosynechococcus elongatus is expressed in cyanobacterial cells and interacts with a large Rubisco subunit (RbcL). Using a heterologous expression system, it was demonstrated that this protein promotes Rubisco assembly in Escherichia coli cells. Moreover, when co-expressed with RbcL alone, a stable RbcL-RAF1 complex is formed. Molecular mass determination for this Rubisco assembly intermediate by size-exclusion chromatography coupled with multi-angle light scattering indicates that it consists of an RbcL dimer and two RAF1 molecules. A purified RbcL-RAF1 complex dissociated upon addition of a small Rubisco subunit (RbcS), leading to formation of the active holoenzyme. Moreover, titration of the octameric (RbcL8) core of Rubisco with RAF1 results in disassembly of such a stucture and creation of an RbcL-RAF1 intermediate. The results presented here are the first attempt to elucidate the role of cyanobacterial Rubisco Accumulation Factor 1 in the Rubisco biosynthesis process. PMID:25041569

Kolesinski, Piotr; Belusiak, Iwona; Czarnocki-Cieciura, Mariusz; Szczepaniak, Andrzej

2014-09-01

91

Graph Grammars for Self Assembling Robotic Systems  

E-print Network

, their conformations change (mechanically for example), thereby determining in what future assembly interactions by the second part of the rule to achieve a new state of the system. We are in particular interested in (1) the situation where the parts decide in a distributed fashion whether and how to execute an assembly rule and (2

Ghrist, Robert W.

92

Fuel assembly skeleton compaction  

Microsoft Academic Search

The fuel assembly skeleton compaction system provides a means for remotely dismantling an irradiated nuclear fuel assembly skeleton once the nuclear fuel rods have been removed therefrom while the skeleton remains submerged in a coolant. The system comprises a feed chamber for holding the spent fuel assembly skeleton and for feeding a spent fuel assembly skeleton into a shear chamber

J. J. Wilhelm; R. F. Antol; A. Kapoor; R. M. Kobuck; G. W. Norris

1985-01-01

93

Corner-cutting mining assembly  

Microsoft Academic Search

This invention resulted from a contract with the United States Department of Energy and relates to a mining tool. More particularly, the invention relates to an assembly capable of drilling a hole having a square cross-sectional shape with radiused corners. In mining operations in which conventional auger-type drills are used to form a series of parallel, cylindrical holes in a

1981-01-01

94

Modeling and design of a new core-moderator assembly and neutron beam ports for the Penn State Breazeale Nuclear Reactor (PSBR)  

NASA Astrophysics Data System (ADS)

This study is for modeling and designing a new reactor core-moderator assembly and new neutron beam ports that aimed to expand utilization of a new beam hall of the Penn State Breazeale Reactor (PSBR). The PSBR is a part of the Radiation Science and Engineering Facility (RSEC) and is a TRIGA MARK III type research reactor with a movable core placed in a large pool and is capable to produce 1MW output. This reactor is a pool-type reactor with pulsing capability up to 2000 MW for 10-20 msec. There are seven beam ports currently installed to the reactor. The PSBR's existing core design limits the experimental capability of the facility, as only two of the seven available neutron beam ports are usable. The finalized design features an optimized result in light of the data obtained from neutronic and thermal-hydraulics analyses as well as geometrical constraints. A new core-moderator assembly was introduced to overcome the limitations of the existing PSBR design, specifically maximizing number of available neutron beam ports and mitigating the hydrogen gamma contamination of the neutron beam channeled in the beam ports. A crescent-shaped moderator is favored in the new PSBR design since it enables simultaneous use of five new neutron beam ports in the facility. Furthermore, the crescent shape sanctions a coupling of the core and moderator, which reduces the hydrogen gamma contamination significantly in the new beam ports. A coupled MURE and MCNP5 code optimization analysis was performed to calculate the optimum design parameters for the new PSBR. Thermal-hydraulics analysis of the new design was achieved using ANSYS Fluent CFD code. In the current form, the PSBR is cooled by natural convection of the pool water. The driving force for the natural circulation of the fluid is the heat generation within the fuel rods. The convective heat data was generated at the reactor's different operating powers by using TRIGSIMS, the fuel management code of the PSBR core. In the CFD modeling, the amount of heat generated by the fuel is assumed to be transferred totally into the coolant. Therefore, the surface heat flux is applied to the fuel cladding outer surface by considering the depleted fuel composition of each individual fuel rod under a reference core loading condition defined as; 53H at 1MW full power. In order to model the entire PSBR reactor, fine mesh discretization was achieved with 22 millions structured and unstructured computational meshes. The conductive heat transfer inside the fuel rods was ignored in order to decrease the computational mesh requirement. Since the PSBR core operates in the subcooled nucleate boiling region, the CFD simulation of new PSBR design was completed utilizing an Eulerian-Eulerian multiphase flow formulation and RPI wall boiling model. The simulation results showed that the new moderator tank geometry results in secondary flow entering into the core due to decrease in the cross-flow area. Notably, the radial flow improves the local heat transfer conditions by providing radial-mixing in the core. Bubble nucleation occurs on the heated fuel rods but bubbles are collapsing in the subcooled fluid. Furthermore, the bulk fluid properties are not affected by the bubble formation. Yet, subcooled boiling enhances the heat transfer on the fuel rods. Five neutron beam ports are designed for the new reactor. The geometrical configuration, filter and collimator system designs of each neutron beam ports are selected based on the requirements of the experimental facilities. A cold neutron beam port which utilizes cold neutrons from three curved guide tubes is considered. Therefore, there will be seven neutron beams available in the new facility. The neutronic analyses of the new beam port designs were achieved by using MCNP5 code and Burned Coupled Simulation Tool for the PSBR. The MCNP simulation results showed that thermal neutron flux was increased by a factor of minimum 1.23 times and maximum 2.68 times in the new beam port compared to the existing BP4 design. Besides total gamma dose was decreased by a factor

Ucar, Dundar

95

Inlet nozzle assembly  

DOEpatents

An inlet nozzle assembly for directing coolant into the duct tube of a fuel assembly attached thereto. The nozzle assembly includes a shell for housing separable components including an orifice plate assembly, a neutron shield block, a neutron shield plug, and a diffuser block. The orifice plate assembly includes a plurality of stacked plates of differently configurated and sized openings for directing coolant therethrough in a predesigned flow pattern.

Christiansen, David W. (Kennewick, WA); Karnesky, Richard A. (Richland, WA); Precechtel, Donald R. (Richland, WA); Smith, Bob G. (Richland, WA); Knight, Ronald C. (Richland, WA)

1987-01-01

96

Inlet nozzle assembly  

DOEpatents

An inlet nozzle assembly for directing coolant into the duct tube of a fuel assembly attached thereto. The nozzle assembly includes a shell for housing separable components including an orifice plate assembly, a neutron shield block, a neutron shield plug, and a diffuser block. The orifice plate assembly includes a plurality of stacked plates of differently configurated and sized openings for directing coolant therethrough in a predesigned flow pattern.

Christiansen, D.W.; Karnesky, R.A.; Knight, R.C.; Precechtel, D.R.; Smith, B.G.

1985-09-09

97

CISA: Contig Integrator for Sequence Assembly of Bacterial Genomes  

PubMed Central

A plethora of algorithmic assemblers have been proposed for the de novo assembly of genomes, however, no individual assembler guarantees the optimal assembly for diverse species. Optimizing various parameters in an assembler is often performed in order to generate the most optimal assembly. However, few efforts have been pursued to take advantage of multiple assemblies to yield an assembly of high accuracy. In this study, we employ various state-of-the-art assemblers to generate different sets of contigs for bacterial genomes. A tool, named CISA, has been developed to integrate the assemblies into a hybrid set of contigs, resulting in assemblies of superior contiguity and accuracy, compared with the assemblies generated by the state-of-the-art assemblers and the hybrid assemblies merged by existing tools. This tool is implemented in Python and requires MUMmer and BLAST+ to be installed on the local machine. The source code of CISA and examples of its use are available at http://sb.nhri.org.tw/CISA/. PMID:23556006

Lin, Shin-Hung; Liao, Yu-Chieh

2013-01-01

98

19 CFR 10.18 - Valuation of assembled articles.  

Code of Federal Regulations, 2010 CFR

...Customs Duties 1 2010-04-01 2010-04-01 false Valuation of assembled articles. 10.18 Section 10.18 Customs...Assembled Abroad with United States Components § 10.18 Valuation of assembled articles. As in the case of the...

2010-04-01

99

Membrane module assembly  

DOEpatents

A membrane module assembly is described which is adapted to provide a flow path for the incoming feed stream that forces it into prolonged heat-exchanging contact with a heating or cooling mechanism. Membrane separation processes employing the module assembly are also disclosed. The assembly is particularly useful for gas separation or pervaporation. 2 figures.

Kaschemekat, J.

1994-03-15

100

Membrane module assembly  

DOEpatents

A membrane module assembly adapted to provide a flow path for the incoming feed stream that forces it into prolonged heat-exchanging contact with a heating or cooling mechanism. Membrane separation processes employing the module assembly are also disclosed. The assembly is particularly useful for gas separation or pervaporation.

Kaschemekat, Jurgen (Palo Alto, CA)

1994-01-01

101

Cage redesign explains assembly  

PubMed Central

Control of protein self-assembly and disassembly, which is central to metabolism and engineering applications, remains challenging. Here, a perspicacious redesign of interfaces in the multisubunit ferritin protein cage provides single, modifiable subunits that assemble with Cu2+ templating and give insights into the cage assembly code. PMID:23416399

Theil, Elizabeth C; Turano, Paola

2013-01-01

102

Free-energy landscape for peptide amphiphile self-assembly: stepwise versus continuous assembly mechanisms.  

PubMed

The mechanism of self-assembly of 140 peptide amphiphiles (PAs) to give nanofiber structures was investigated using a coarse-grained method to quantitatively determine whether the assembly process involves discrete intermediates or is a continuous process. Two novel concepts are introduced for this analysis, a cluster analysis of the time dependence of PA assembly and use of the fraction of native contacts as reaction coordinates for characterizing thermodynamic functions during assembly. The cluster analysis of the assembly kinetics demonstrates that a pillar-like intermediate state is formed before the final cylindrical semifiber structure. We also find that head group assembly occurs on a much shorter time scale than tail group assembly. A 2D free-energy landscape with respect to the fraction of native contacts was calculated, and the pillar-like intermediate structure was also found, with free energies about 1.2 kcal/mol higher than the final state. Although this intermediate state exists for only hundreds of nanoseconds, the PA self-assembly process can be recognized as involving two steps, (a) transition from the disordered state to the noncylindrical pillar-like intermediate and (b) pillar-like to final semifiber transition. These results are important to the further design of PAs as functional nanostructures. PMID:24143994

Yu, Tao; Schatz, George C

2013-11-14

103

Telerobotic truss assembly  

NASA Technical Reports Server (NTRS)

The ACCESS truss was telerobotically assembled in order to gain experience with robotic assembly of hardware designed for astronaut extravehicular (EVA) assembly. Tight alignment constraints of the ACCESS hardware made telerobotic assembly difficult. A wider alignment envelope and a compliant end effector would have reduced the problem. The manipulator had no linear motion capability, but many of the assembly operations required straight line motion. The manipulator was attached to a motion table in order to provide the X, Y, and Z translations needed. A programmable robot with linear translation capability would have eliminated the need for the motion table and streamlined the assembly. Poor depth perception was a major problem. Shaded paint schemes and alignment lines were helpful in reducing this problem. The four cameras used worked well for only some operations. It was not possible to identify camera locations that worked well for all assembly steps. More cameras or movable cameras would have simplified some operations. The audio feedback system was useful.

Sheridan, Philip L.

1987-01-01

104

Exploring contribution of intermolecular interactions in supramolecular layered assembly of naphthyridine co-crystals: Insights from Hirshfeld surface analysis of their crystalline states  

NASA Astrophysics Data System (ADS)

Co-crystals of 1a and 1b have been prepared by slow evaporation of the solutions of mixtures of 2,7-dimethyl-1,8-naphthyridine (1), urea (a) and thiourea (b). The structures of the complexes are determined by the single crystal X-ray diffraction and a detailed investigation of the crystal packing and classification of intermolecular interactions is presented by means of Hirshfeld surface analysis which is of considerable current interest in crystal engineering. The X-ray study reveals that the co-crystal formers are envisioned to produce N-H⋯N hydrogen bond as well as N-H⋯O/N-H⋯S pair-wise hydrogen bonds and also the weaker aromatic ?⋯? interactions which cooperatively take part in the crystal packing. The recurring feature of the self-assembly in the compounds is the appearance of the molecular ribbon through multiple hydrogen bonding which are further stacked into molecular layers by ?⋯? stacking interactions. Hirshfeld surface analysis for visually analyzing intermolecular interactions in crystal structures employing molecular surface contours and 2D Fingerprint plots have been used to examine molecular shapes. Crystal structure analysis supported with the Hirshfeld surface and fingerprint plots enabled the identification of the significant intermolecular interactions.

Seth, Saikat Kumar; Das, Nirmal Kumar; Aich, Krishnendu; Sen, Debabrata; Fun, Hoong-Kun; Goswami, Shyamaprasad

2013-09-01

105

Computing by molecular self-assembly  

PubMed Central

The paper reviews two computing models by DNA self-assembly whose proof of principal have recently been experimentally confirmed. The first model incorporates DNA nano-devices and triple crossover DNA molecules to algorithmically arrange non-DNA species. This is achieved by simulating a finite-state automaton with output where golden nanoparticles are assembled to read-out the result. In the second model, a complex DNA molecule representing a graph emerges as a solution of a computational problem. This supports the idea that in molecular self-assembly computing, it may be necessary to develop the notion of shape processing besides the classical approach through symbol processing. PMID:23919130

Jonoska, Natasa; Seeman, Nadrian C.

2012-01-01

106

Computing by molecular self-assembly.  

PubMed

The paper reviews two computing models by DNA self-assembly whose proof of principal have recently been experimentally confirmed. The first model incorporates DNA nano-devices and triple crossover DNA molecules to algorithmically arrange non-DNA species. This is achieved by simulating a finite-state automaton with output where golden nanoparticles are assembled to read-out the result. In the second model, a complex DNA molecule representing a graph emerges as a solution of a computational problem. This supports the idea that in molecular self-assembly computing, it may be necessary to develop the notion of shape processing besides the classical approach through symbol processing. PMID:23919130

Jonoska, Nataša; Seeman, Nadrian C

2012-08-01

107

Photovoltaic assemblies and methods for transporting  

DOEpatents

A PV assembly including framework, PV laminate(s), and a stiffening device. The framework includes a perimeter frame at least 10 feet in length and at least 5 feet in width. The PV laminate(s) are assembled to the perimeter frame to define a receiving zone having a depth of not more than 8 inches. The stiffening device is associated with the framework and is configured to provide a first state and a second state. In the first state, an entirety of the stiffening device is maintained within the receiving zone. In the second state, at least a portion of the stiffening device projects from the receiving zone. The stiffening device enhances a stiffness of the PV assembly in a plane of the perimeter frame, and can include rods defining truss structures.

Almy, Charles; Campbell, Matt; Sandler, Reuben; Wares, Brian; Wayman, Elizabeth

2013-09-17

108

Linux Assembly HOWTO  

NSDL National Science Digital Library

This tutorial "describes how to program in assembly language using free programming tools, focusing on development for or from the Linux Operating System." For applications that are closely related to the underlying computer architecture, assembly language programming can be very important. The instructive material is aimed at people who have at least a basic understanding of conventional, high-level programming styles but have little to no experience with assembly. Hence, it serves as a general introduction to the topic, mainly useful for understanding what situations lend themselves to assembly programming.

Boldyshev, Konstantin.; Rideau, Francois-Rene.

2005-12-22

109

Statement on New Jersey State Assembly Resolution 135 The Institute for Advanced Study supports the preservation of the Princeton Battlefield and  

E-print Network

engagements were fought in New Jersey than in any5 other state; and6 WHEREAS, At the battles of Trenton the Battle of Princeton as a turning point in the Revolutionary War. June 14, 2011 phone (609) 734 and his15 troops marched to Trenton, attacked the garrison there, and16 captured approximately 900 Hessian

110

Enhancement of monobasal solid-state dye-sensitized solar cells with polymer electrolyte assembling imidazolium iodide-functionalized silica nanoparticles  

NASA Astrophysics Data System (ADS)

An alkyl imidazolium iodide-functionalized silica (SiO2-ImI)/PEO/PVDF nano-composite polymer electrolyte (CPE) is developed for the monobasal solid-state dye-sensitized solar cell (DSSC) based on a printable carbon counter electrode. The results indicate that the alkyl imidazolium iodide chemically engineered onto the surface of silica, and that the SiO2-ImI can be distributed more uniformly in the PEO/PVDF polymer matrix than bare SiO2 nanoparticles. Electrochemical impedance spectroscopy (EIS) tests reveal that the conductivity of SiO2-ImI CPE is greatly increased compared with pure polymer electrolyte or the bare SiO2 CPE. As a result, the highest ionic conductivity of 1.07 × 10-4 S cm-1 and a power conversion efficiency of 3.83% is obtained at AM 1.5 and 100 mW cm-2 with the 8 wt% SiO2-ImI CPE based monobasal solid-state DSSCs. Moreover, the preliminary stability tests indicate that SiO2-ImI CPE based monobasal solid-state DSSCs present better stability than bare SiO2 CPE devices.

Hu, Min; Sun, Jiazeng; Rong, Yaoguang; Yang, Ying; Liu, Linfeng; Li, Xiong; Forsyth, Maria; MacFarlane, Douglas R.; Han, Hongwei

2014-02-01

111

Battery separator assembly  

Microsoft Academic Search

A separator assembly for use in batteries is described comprising a film bearing a thermal fuse in the form of a layer of wax coated fibers; wherein the assembly is sufficiently porous to allow continuous flow of ions in the battery.

M. A. Faust; M. R. Suchanski; H. W. Osterhoudt

1988-01-01

112

Inorganic self-assembly  

Microsoft Academic Search

Self-assembly processes provide an effective and environmentally benign method for synthesising novel ceramic and composite materials. The development of self-assembly methodology, which is the archetypal bioinspired synthesis route, has greatly expanded the methods of producing nanostructures. In the design of complex materials such as electrical devices, we currently rely on our ability to create designed patterns lithographically. New ways of

Laura E Depero; M Lucia Curri

2004-01-01

113

Assembly Language Programming Manual  

E-print Network

assembly language programming for Zilog's Z8 single-chip microcomputer. The first three sections, and run Z8 assembly-language programs. Programs are developed on either Zilog's microcomputer system (MCZ information: Z8 Microcomputer Technical Manual, 03-3047-02 iii #12;#12;SECTION 1 SECTION 2 Contents

Hughes, Larry

114

Assembly oriented design  

Microsoft Academic Search

Product design is still commonly component rather than assembly oriented. Industry requirements have inspired a more holistic approach which is presented here. In this, proactive DFA is used in a process centred around assembly sequence construction. Early analysis and evaluation is enabled by geometric reasoning and expert system tools. Details of underlying principles and implementation are given together with a

C. J. Barnes; G. F. Dalgleish; G. E. M. Jared; H. Mei; K. G. Swift

1999-01-01

115

Turbine disc sealing assembly  

DOEpatents

A disc seal assembly for use in a turbine engine. The disc seal assembly includes a plurality of outwardly extending sealing flange members that define a plurality of fluid pockets. The sealing flange members define a labyrinth flow path therebetween to limit leakage between a hot gas path and a disc cavity in the turbine engine.

Diakunchak, Ihor S.

2013-03-05

116

Superconductive radiofrequency window assembly  

DOEpatents

The present invention is a superconducting radiofrequency window assembly for use in an electron beam accelerator. The SRF window assembly has a superconducting metal-ceramic design. The SRF window assembly comprises a superconducting frame, a ceramic plate having a superconducting metallized area, and a superconducting eyelet for sealing plate into frame. The plate is brazed to eyelet which is then electron beam welded to frame. A method for providing a ceramic object mounted in a metal member to withstand cryogenic temperatures is also provided. The method involves a new metallization process for coating a selected area of a ceramic object with a thin film of a superconducting material. Finally, a method for assembling an electron beam accelerator cavity utilizing the SRF window assembly is provided. The procedure is carried out within an ultra clean room to minimize exposure to particulates which adversely affect the performance of the cavity within the electron beam accelerator. 11 figs.

Phillips, H.L.; Elliott, T.S.

1998-05-19

117

Superconducting radiofrequency window assembly  

DOEpatents

The present invention is a superconducting radiofrequency window assembly for use in an electron beam accelerator. The srf window assembly has a superconducting metal-ceramic design. The srf window assembly comprises a superconducting frame, a ceramic plate having a superconducting metallized area, and a superconducting eyelet for sealing plate into frame. The plate is brazed to eyelet which is then electron beam welded to frame. A method for providing a ceramic object mounted in a metal member to withstand cryogenic temperatures is also provided. The method involves a new metallization process for coating a selected area of a ceramic object with a thin film of a superconducting material. Finally, a method for assembling an electron beam accelerator cavity utilizing the srf window assembly is provided. The procedure is carried out within an ultra clean room to minimize exposure to particulates which adversely affect the performance of the cavity within the electron beam accelerator. 11 figs.

Phillips, H.L.; Elliott, T.S.

1997-03-11

118

Automated assembly in space  

NASA Technical Reports Server (NTRS)

The installation of robots and their use of assembly in space will create an exciting and promising future for the U.S. Space Program. The concept of assembly in space is very complicated and error prone and it is not possible unless the various parts and modules are suitably designed for automation. Certain guidelines are developed for part designing and for an easy precision assembly. Major design problems associated with automated assembly are considered and solutions to resolve these problems are evaluated in the guidelines format. Methods for gripping and methods for part feeding are developed with regard to the absence of gravity in space. The guidelines for part orientation, adjustments, compliances and various assembly construction are discussed. Design modifications of various fasteners and fastening methods are also investigated.

Srivastava, Sandanand; Dwivedi, Suren N.; Soon, Toh Teck; Bandi, Reddy; Banerjee, Soumen; Hughes, Cecilia

1989-01-01

119

Integrated accelerometer assembly  

NASA Astrophysics Data System (ADS)

An integrated assembly is provided for a dry accelerometer of the pendulous mass type. The assembly includes a planar support base having an aperture in the center and a pendulous member including two arms. A pair of spaced flexible hinges having a first end of each attached to the support base and a second end of each attached to one of the arms pivotally support the pendulous member within the aperture. A pair of limit stops welded to opposed sides of the support base limit the movement of the pendulous member. The support base includes a plurality of apertures for anchoring the hinge welds and limit stop welds and the pendulous member includes a plurality of copper filled apertures for anchoring the hinge welds. Procedures for fabrication of the integrated assembly are also disclosed. The invention provides a means for relatively inexpensive and easy fabrication of dry accelerometer assemblies having less loss of accuracy over time compared to assemblies of the prior art.

Abbink, Henry C.; Pier, Nicholas F.

1993-09-01

120

Constrained space camera assembly  

DOEpatents

A constrained space camera assembly which is intended to be lowered through a hole into a tank, a borehole or another cavity. The assembly includes a generally cylindrical chamber comprising a head and a body and a wiring-carrying conduit extending from the chamber. Means are included in the chamber for rotating the body about the head without breaking an airtight seal formed therebetween. The assembly may be pressurized and accompanied with a pressure sensing means for sensing if a breach has occurred in the assembly. In one embodiment, two cameras, separated from their respective lenses, are installed on a mounting apparatus disposed in the chamber. The mounting apparatus includes means allowing both longitudinal and lateral movement of the cameras. Moving the cameras longitudinally focuses the cameras, and moving the cameras laterally away from one another effectively converges the cameras so that close objects can be viewed. The assembly further includes means for moving lenses of different magnification forward of the cameras.

Heckendorn, Frank M. (Aiken, SC); Anderson, Erin K. (Augusta, GA); Robinson, Casandra W. (Trenton, SC); Haynes, Harriet B. (Aiken, SC)

1999-01-01

121

Fuel assembly with a removable end fitting  

SciTech Connect

A typical embodiment of the invention provides a nuclear fuel assembly lock structure for control rod guide tubes. Illustratively, a sleeve telescopes over an end portion of a control rod guide tube which bears against an internal shoulder of the tube. The upper end of the sleeve protrudes beyond the control rod guide tube spider and is locked in place by means of a resilient cellular lattice or lock that is seated in a mating groove in the outer surface of the sleeve. A special tool is provided for disengaging the entire lock structure, washer, spider, spring and grill from the end of the fuel assembly in order to enable these components to be removed in an assembled state and subsequently replaced on the fuel assembly after inspection and repair.

Jabsen, F.S.

1980-06-17

122

Next-generation sequencing and large genome assemblies  

PubMed Central

The next-generation sequencing (NGS) revolution has drastically reduced time and cost requirements for sequencing of large genomes, and also qualitatively changed the problem of assembly. This article reviews the state of the art in de novo genome assembly, paying particular attention to mammalian-sized genomes. The strengths and weaknesses of the main sequencing platforms are highlighted, leading to a discussion of assembly and the new challenges associated with NGS data. Current approaches to assembly are outlined and the various software packages available are introduced and compared. The question of whether quality assemblies can be produced using short-read NGS data alone, or whether it must be combined with more expensive sequencing techniques, is considered. Prospects for future assemblers and tests of assembly performance are also discussed. PMID:22676195

Henson, Joseph; Tischler, German; Ning, Zemin

2012-01-01

123

Automated Assembly Using Feature Localization  

E-print Network

Automated assembly of mechanical devices is studies by researching methods of operating assembly equipment in a variable manner; that is, systems which may be configured to perform many different assembly operations ...

Gordon, Steven Jeffrey

1986-12-01

124

Resolution and measurement of heteronuclear dipolar couplings of a noncrystalline protein immobilized in a biological supramolecular assembly by proton-detected MAS solid-state NMR spectroscopy  

NASA Astrophysics Data System (ADS)

Two-dimensional 15N chemical shift/1H chemical shift and three-dimensional 1H-15N dipolar coupling/15N chemical shift/1H chemical shift MAS solid-state NMR correlation spectra of the filamentous bacteriophage Pf1 major coat protein show single-site resolution in noncrystalline, intact-phage preparations. The high sensitivity and resolution result from 1H detection at 600 MHz under 50 kHz magic angle spinning using ˜0.5 mg of perdeuterated and uniformly 15N-labeled protein in which the exchangeable amide sites are partially or completely back-exchanged (reprotonated). Notably, the heteronuclear 1H-15N dipolar coupling frequency dimension is shown to select among 15N resonances, which will be useful in structural studies of larger proteins where the resonances exhibit a high degree of overlap in multidimensional chemical shift correlation spectra.

Park, Sang Ho; Yang, Chen; Opella, Stanley J.; Mueller, Leonard J.

2013-12-01

125

Dual flapper valve assembly  

SciTech Connect

This patent describes a dual flapper valve assembly for limiting the loss of completion fluid in connection with a well service operation. The valve assembly consists of: tubular support means defining a flow passage; a first flapper valve assembly connected in series flow relation with the support means, the first flapper valve assembly having a valve closure member movable between first and second positions for closing and opening the flow passage; a second flapper valve assembly connected in series flow relation in the support means, the second flapper valve assembly having a valve closure member movable between open and closed passage positions for closing and opening the flow passage; a prop sleeve mounted within the support means, the prop sleeve being movable from an extended position in which it props the closure member of one flapper valve in the open passage position to a retracted position in which the closure member is disengaged and released for movement to the closed passage position, the valve closure member of one of the flapper valve assemblies being engageable by a wash pipe extending through the flow passage to prop the valve closure member in the open passage position, and being movable to the closed passage position upon retraction of the wash pipe out of the flow passage.

Clary, S.R.; Giusti, F. Jr.; Sproul, R.M.

1989-07-11

126

TPX assembly plan  

SciTech Connect

The TPX machine will be assembled in the TFTR Test Cell at the Plasma Physics Laboratory, utilizing the existing TFTR machine foundation. Preparation of the area for assembly will begin after completion of the decontamination and decommissioning phase on TFTR and certification that the radiation levels remaining, if any, are consistent with the types of operations planned. Assembly operations begin with the arrival of the first components, and conclude, approximately 24 months later, with the successful completion of the integrated systems tests and the achievement of a first plasma.

Knutson, D.

1993-11-01

127

United Nations General Assembly  

NSDL National Science Digital Library

The UN Department of Public Information has recently created a site which features comprehensive information on its General Assembly. The core of the site is a collection of facts and documents relating to the current (52nd) meeting of the General Assembly. Users find the Agenda and Programme of Work, recent press releases, links to documents, and information on committees, elections, and appointments. Information and documents from previous regular and special sessions are also available. An added feature is a general description of the Assembly itself: its background, functions, sessions, and main committees.

128

Lock mandrel latch assembly  

SciTech Connect

This patent describes a latch assembly for preliminarily latching a lock mandrel into a locking annulus in a landing nipple in a wellbore. The latch assembly being disposed in a window in a sidewall of the lock mandrel; the latch assembly further comprises a pawl rotatably mounted about an axis traversing the window, a shear pin traversing the window below the pawl, and means for biasing the pawl against the shear pin; the pawl being further adapted to extend radially outward through the window in the sidewall of the lock mandrel to engage the locking annulus in the landing nipple when the pawl is biased against the shear pin.

Welch, W.R.

1991-03-05

129

Predicting the self-assembly of a model colloidal crystal  

Microsoft Academic Search

We investigate the self-assembly (crystallisation) of particles with hard cores and isotropic, square-well interactions, using a Monte Carlo scheme to simulate overdamped Langevin dynamics. We measure correlation and response functions during the early stages of assembly, and we analyse the results using fluctuation-dissipation theorems, aiming to predict which systems will self-assemble successfully and which will get stuck in disordered states.

Daphne Klotsa; Robert L. Jack

2011-01-01

130

Theory and experiments of transport at channel microband electrodes under laminar flows. 2. Electrochemical regimes at double microband assemblies under steady state.  

PubMed

The development of any particular analytical or preparative applications using electrochemical techniques in microfluidic devices requires integration of microelectrodes. This involves detailed predictions for optimizing the design of devices and selecting the best hydrodynamic conditions. For this purpose, we undertook a series of works aimed at a precise investigation of mass transport near electrodes with focus on analytical measurements. Part I of this series (Anal. Chem. 2007, 79, 8502-8510) evaluated the common case of a single microband electrode embedded within a microchannel under laminar flow. The present work (Part 2) investigated the case of a pair of microband electrodes operating either in generator-generator or generator-collector modes. The influence of the confining effect and flow velocity on the amperometric responses was examined on the basis of numerical simulations under steady-state regime. Several situations were identified, each of them corresponding to specific interactions taking place between the electrodes. Related conditions were extracted to establish a zone diagram describing all the situations. These predictions were systematically validated by experimental measurements. The results show that amperometric detections within microchannels can be performed at dual electrodes with higher analytical performances than at single ones. PMID:19007242

Amatore, Christian; Da Mota, Nicolas; Lemmer, Célia; Pebay, Cécile; Sella, Catherine; Thouin, Laurent

2008-12-15

131

Modifications under irradiation of a self-assembled monolayer grafted on a nano-porous silica glass: a solid-state NMR characterization  

SciTech Connect

Controlled pore glasses with a pore size of 8 nm are grafted with chlorodimethylsilane (ClSi(CH{sub 3}){sub 2}H). The surface of the glass is carefully characterized before and after irradiation with 10 MeV electrons by solid-state NMR measurements. {sup 1}H MAS NMR experiments in one and two dimensions (2D double quantum and 2D exchange) have been used to reveal the grafting of the chlorodimethylsilane at the silica surface and evidence the formation of a homogeneous layer on the surface. Irradiation leads to a high H{sub 2} yield (3.3 * 10{sup -7} mol/J) due to the efficient cleavage of the Si H bond. Methane is detected in smaller quantities (5.5 * 10{sup -8} mol/J), indicating that the Si-H bond is preferentially cleaved over the Si-C bond. The H{sub 2} production arising from OH groups on the surface is very minor in comparison to the S- H and Si-C radiolysis. (authors)

Le Caer, S.; Chatelain, C.; Renault, J.Ph. [CEA, CNRS, Inst Rayonnement Mat Saclay, Lab Radiolyse, SIS2M, Serv Interdisciplinaire Syst Mol et Mat, UMR 3299, F-91191 Gif Sur Yvette, (France); Brunet, F.; Charpentier, T. [CEA, Lab Struct et Dynam Resonance Magnet, CNRS, Inst Rayonnement Mat Saclay, SIS2M, Serv Interdisciplinaire Syst Mol et Mat, UMR 3299, F-91191 Gif Sur Yvette, (France); Durand, D.; Dauvois, V. [CEA Saclay, DEN, DANS, DPC, SECR, LSRM, F-91191 Gif Sur Yvette, (France)

2012-02-15

132

Swipe transfer assembly  

DOEpatents

The swipe transfer assembly is a mechanical assembly which is used in conjunction with glove boxes and other sealed containments. It is used to pass small samples into or out of glove boxes without an open breach of the containment, and includes a rotational cylinder inside a fixed cylinder, the inside cylinder being rotatable through an arc of approximately 240.degree. relative to the outer cylinder. An offset of 120.degree. from end to end allows only one port to be opened at a time. The assembly is made of stainless steel or aluminum and clear acrylic plastic to enable visual observation. The assembly allows transfer of swipes and smears from radiological and other specially controlled environments.

Christiansen, Robert M. (Blackfoot, ID); Mills, William C. (McKeesport, PA)

1992-01-01

133

Flexseal Insulator Test Assembly  

NASA Technical Reports Server (NTRS)

Small-scale version of solid-fuel rocket motor flexseal nozzle bearing assembly instrumented and tested in compression-testing fixture simulating conditions during rocket motor operation described in report.

Buchanan, Eric

1995-01-01

134

Magnetic assisted statistical assembly  

E-print Network

The objective of this thesis is to develop a process using magnetic forces to assemble micro-components into recesses on silicon based integrated circuits. Patterned SmCo magnetic thin films at the bottom of recesses are ...

Cheng, Diana I

2008-01-01

135

Steam separator latch assembly  

DOEpatents

A latch assembly removably joins a steam separator assembly to a support flange disposed at a top end of a tubular shroud in a nuclear reactor pressure vessel. The assembly includes an annular head having a central portion for supporting the steam separator assembly thereon, and an annular head flange extending around a perimeter thereof for supporting the head to the support flange. A plurality of latches are circumferentially spaced apart around the head flange with each latch having a top end, a latch hook at a bottom end thereof, and a pivot support disposed at an intermediate portion therebetween and pivotally joined to the head flange. The latches are pivoted about the pivot supports for selectively engaging and disengaging the latch hooks with the support flange for fixedly joining the head to the shroud or for allowing removal thereof.

Challberg, Roy C. (Livermore, CA); Kobsa, Irvin R. (San Jose, CA)

1994-01-01

136

Rnnotator Assembly Pipeline  

SciTech Connect

Jeff Martin of the DOE Joint Genome Institute discusses a de novo transcriptome assembly pipeline from short RNA-Seq reads on June 3, 2010 at the "Sequencing, Finishing, Analysis in the Future" meeting in Santa Fe, NM

Martin, Jeff [DOE Joint Genome Institute

2010-06-03

137

Magnetostrictive valve assembly  

NASA Technical Reports Server (NTRS)

A magnetostrictive valve assembly includes a housing that defines a passage with a seat being formed therein. A magnetically-biased and axially-compressed magnetostrictive assembly slidingly fitted in the passage is configured as a hollow and open-ended conduit adapted to support a flow of a fluid therethrough. Current-carrying coil(s) disposed about the passage in the region of the magnetostrictive assembly generate a magnetic field in the passage when current flows through the coil(s). A hollow valve body with side ports is coupled on one end thereof to an axial end of the magnetostrictive assembly. The other end of the valve body is designed to seal with the seat formed in the housing's passage when brought into contact therewith.

Richard, James A. (Inventor)

2008-01-01

138

High speed door assembly  

SciTech Connect

This invention is comprised of a high speed door assembly, comprising an actuator cylinder and piston rods, a pressure supply cylinder and fittings, an electrically detonated explosive bolt, a honeycomb structured door, a honeycomb structured decelerator, and a structural steel frame encasing the assembly to close over a 3 foot diameter opening within 50 milliseconds of actuation, to contain hazardous materials and vapors within a test fixture.

Shapiro, C.

1991-12-31

139

VIRUS instrument collimator assembly  

NASA Astrophysics Data System (ADS)

The Visual Integral-Field Replicable Unit Spectrograph (VIRUS) instrument is a baseline array 150 identical fiber fed optical spectrographs designed to support observations for the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX). The collimator subassemblies of the instrument have been assembled in a production line and are now complete. Here we review the design choices and assembly practices used to produce a suite of identical low-cost spectrographs in a timely fashion using primarily unskilled labor.

Marshall, Jennifer L.; DePoy, Darren L.; Prochaska, Travis; Allen, Richard D.; Williams, Patrick; Rheault, Jean-Philippe; Li, Ting; Nagasawa, Daniel Q.; Akers, Christopher; Baker, David; Boster, Emily; Campbell, Caitlin; Cook, Erika; Elder, Alison; Gary, Alex; Glover, Joseph; James, Michael; Martin, Emily; Meador, Will; Mondrik, Nicholas; Rodriguez-Patino, Marisela; Villanueva, Steven; Hill, Gary J.; Tuttle, Sarah; Vattiat, Brian; Lee, Hanshin; Chonis, Taylor S.; Dalton, Gavin B.; Tacon, Mike

2014-07-01

140

Genome assembly forensics: finding the elusive mis-assembly  

PubMed Central

We present the first collection of tools aimed at automated genome assembly validation. This work formalizes several mechanisms for detecting mis-assemblies, and describes their implementation in our automated validation pipeline, called amosvalidate. We demonstrate the application of our pipeline in both bacterial and eukaryotic genome assemblies, and highlight several assembly errors in both draft and finished genomes. The software described is compatible with common assembly formats and is released, open-source, at . PMID:18341692

Phillippy, Adam M; Schatz, Michael C; Pop, Mihai

2008-01-01

141

Complete Genome Assembly of Staphylococcus epidermidis AmMS 205.  

PubMed

Staphylococcus epidermidis causes a large number of catheter-related sepsis infections annually in the United States. We present the 2.54-Mbp complete genome assembly of reference strain S. epidermidis AmMS 205, including a single 37.7-kbp plasmid. The annotated assembly is available in GenBank under accession numbers CP009046 and CP009047. PMID:25377697

Davenport, K W; Daligault, H E; Minogue, T D; Bishop-Lilly, K A; Broomall, S M; Bruce, D C; Chain, P S; Coyne, S R; Frey, K G; Gibbons, H S; Jaissle, J; Redden, C L; Rosenzweig, C N; Scholz, M B; Teshima, H; Johnson, S L

2014-01-01

142

Complete Genome Assembly of Staphylococcus epidermidis AmMS 205  

PubMed Central

Staphylococcus epidermidis causes a large number of catheter-related sepsis infections annually in the United States. We present the 2.54-Mbp complete genome assembly of reference strain S. epidermidis AmMS 205, including a single 37.7-kbp plasmid. The annotated assembly is available in GenBank under accession numbers CP009046 and CP009047. PMID:25377697

Davenport, K. W.; Daligault, H. E.; Minogue, T. D.; Bishop-Lilly, K. A.; Broomall, S. M.; Bruce, D. C.; Chain, P. S.; Coyne, S. R.; Frey, K. G.; Gibbons, H. S.; Jaissle, J.; Redden, C. L.; Rosenzweig, C. N.; Scholz, M. B.; Teshima, H.

2014-01-01

143

Energy Distribution of Cluster Assemble with Isomers  

Microsoft Academic Search

The internal energy of cluster assemble without isomers will be a single-peak distribution in thermal equilibrium. However, if it has several isomers and each isomer has different state density distribution, the internal energy distribution will be structured in certain circumstance. By destroying the equilibrium of isomer populations and observing the building-up of the new equilibrium, we can gain information of

Songbai Ye; Louis Bloomfield

2006-01-01

144

Assemblies of Conformal Tanks  

NASA Technical Reports Server (NTRS)

Assemblies of tanks having shapes that conform to each other and/or conform to other proximate objects have been investigated for use in storing fuels and oxidizers in small available spaces in upper stages of spacecraft. Such assemblies might also prove useful in aircraft, automobiles, boats, and other terrestrial vehicles in which space available for tanks is limited. The basic concept of using conformal tanks to maximize the utilization of limited space is not new in itself: for example, conformal tanks are used in some automobiles to store windshield -washer liquid and coolant that overflows from radiators. The novelty of the present development lies in the concept of an assembly of smaller conformal tanks, as distinguished from a single larger conformal tank. In an assembly of smaller tanks, it would be possible to store different liquids in different tanks. Even if the same liquid were stored in all the tanks, the assembly would offer an advantage by reducing the mechanical disturbance caused by sloshing of fuel in a single larger tank: indeed, the requirement to reduce sloshing is critical in some applications. The figure shows a prototype assembly of conformal tanks. Each tank was fabricated by (1) copper plating a wax tank mandrel to form a liner and (2) wrapping and curing layers of graphite/epoxy composite to form a shell supporting the liner. In this case, the conformal tank surfaces are flat ones where they come in contact with the adjacent tanks. A band of fibers around the outside binds the tanks together tightly in the assembly, which has a quasi-toroidal shape. For proper functioning, it would be necessary to maintain equal pressure in all the tanks.

DeLay, Tom

2009-01-01

145

Assembly Test Article (ATA)  

NASA Technical Reports Server (NTRS)

The assembly test article (ATA) consisted of two live loaded redesigned solid rocket motor (RSRM) segments which were assembled and disassembled to simulate the actual flight segment stacking process. The test assembly joint was flight RSRM design, which included the J-joint insulation design and metal capture feature. The ATA test was performed mid-November through 24 December 1987, at Kennedy Space Center (KSC), Florida. The purpose of the test was: certification that vertical RSRM segment mating and separation could be accomplished without any damage; verification and modification of the procedures in the segment stacking/destacking documents; and certification of various GSE to be used for flight assembly and inspection. The RSRM vertical segment assembly/disassembly is possible without any damage to the insulation, metal parts, or seals. The insulation J-joint contact area was very close to the predicted values. Numerous deviations and changes to the planning documents were made to ensure the flight segments are effectively and correctly stacked. Various GSE were also certified for use on flight segments, and are discussed in detail.

Ricks, Glen A.

1988-01-01

146

Superconducting radiofrequency window assembly  

DOEpatents

The present invention is a superconducting radiofrequency window assembly for use in an electron beam accelerator. The srf window assembly (20) has a superconducting metal-ceramic design. The srf window assembly (20) comprises a superconducting frame (30), a ceramic plate (40) having a superconducting metallized area, and a superconducting eyelet (50) for sealing plate (40) into frame (30). The plate (40) is brazed to eyelet (50) which is then electron beam welded to frame (30). A method for providing a ceramic object mounted in a metal member to withstand cryogenic temperatures is also provided. The method involves a new metallization process for coating a selected area of a ceramic object with a thin film of a superconducting material. Finally, a method for assembling an electron beam accelerator cavity utilizing the srf window assembly is provided. The procedure is carried out within an ultra clean room to minimize exposure to particulates which adversely affect the performance of the cavity within the electron beam accelerator.

Phillips, Harry L. (Seaford, VA); Elliott, Thomas S. (Yorktown, VA)

1997-01-01

147

Superconductive radiofrequency window assembly  

DOEpatents

The present invention is a superconducting radiofrequency window assembly for use in an electron beam accelerator. The srf window assembly (20) has a superconducting metal-ceramic design. The srf window assembly (20) comprises a superconducting frame (30), a ceramic plate (40) having a superconducting metallized area, and a superconducting eyelet (50) for sealing plate (40) into frame (30). The plate (40) is brazed to eyelet (50) which is then electron beam welded to frame (30). A method for providing a ceramic object mounted in a metal member to withstand cryogenic temperatures is also provided. The method involves a new metallization process for coating a selected area of a ceramic object with a thin film of a superconducting material. Finally, a method for assembling an electron beam accelerator cavity utilizing the srf window assembly is provided. The procedure is carried out within an ultra clean room to minimize exposure to particulates which adversely affect the performance of the cavity within the electron beam accelerator.

Phillips, Harry Lawrence (Seaford, VA); Elliott, Thomas S. (Yorktown, VA)

1998-01-01

148

Constrained space camera assembly  

DOEpatents

A constrained space camera assembly which is intended to be lowered through a hole into a tank, a borehole or another cavity is disclosed. The assembly includes a generally cylindrical chamber comprising a head and a body and a wiring-carrying conduit extending from the chamber. Means are included in the chamber for rotating the body about the head without breaking an airtight seal formed therebetween. The assembly may be pressurized and accompanied with a pressure sensing means for sensing if a breach has occurred in the assembly. In one embodiment, two cameras, separated from their respective lenses, are installed on a mounting apparatus disposed in the chamber. The mounting apparatus includes means allowing both longitudinal and lateral movement of the cameras. Moving the cameras longitudinally focuses the cameras, and moving the cameras laterally away from one another effectively converges the cameras so that close objects can be viewed. The assembly further includes means for moving lenses of different magnification forward of the cameras. 17 figs.

Heckendorn, F.M.; Anderson, E.K.; Robinson, C.W.; Haynes, H.B.

1999-05-11

149

VideoLab: Assembling a Nanowheel  

NSDL National Science Digital Library

Self-assembly is a powerful means of preparing structurally intricate nanomaterials. However, the challenge of forming large, ring-shaped nanomolecules this way is entropically steep. By using a flow reactor system, Miras et al. observed how (3.5 nm in diameter) form with the help of temporary template molecules. These transient templates form, help assemble the ring-shaped molecules around them, and then leave once the wheel is fully formed and reduced to its final electronic state. This animation shows a model of the templating process.

Haralampos N. Miras (The University of Glasgow, Glasgow;WestCHEM, Department of Chemistry); Geoffrey J. T. Cooper (The University of Glasgow, Glasgow;WestCHEM, Department of Chemistry); De-Liang Long (The University of Glasgow, Glasgow;WestCHEM, Department of Chemistry); Hartmut Bogge (Fakultät für Chemie, Universität Bielefeld, Postfach ;); Achim Muller (Fakultät für Chemie, Universität Bielefeld, Postfach ;); Carsten Streb (The University of Glasgow, Glasgow;WestCHEM, Department of Chemistry)

2010-01-01

150

Perceptions and viewpoints on proceedings of the Fifteenth Assembly of Heads of State and Government of the African Union Debate on Maternal, Newborn and Child Health and Development, 25-27 July 2010, Kampala, Uganda  

PubMed Central

Background Out of 358000 maternal deaths that occurred globally in 2008, 57.8% occurred in continental Africa. Africa had a maternal mortality ratio of 590 compared to 14 in developed regions, 68 in Latin America and Caribbean, and 190 in Asia. This article reflects on the discussions held during the Fifteenth Assembly of the Heads of State and Government of the African Union on the reasons why the maternal mortality ratio is so high in Africa and what can be done to reduce it. Methods Methods employed included panel and open public discussions among the Heads of State and Government of the African Union. The article uses the WHO health systems strengthening framework, which consists of six pillars (information systems, leadership and governance, health workforce, financing, and medical products, vaccines and technologies, and health services) to describe the proceedings of the discussions. Discussion The high maternal mortality ratios in countries were attributed to weak national health information systems; leadership and governance challenges related to poverty, health illiteracy, poor transport networks and communications infrastructure, risky cultural practices, armed conflicts and domestic violence, dearth of women empowerment; inadequate levels of skilled birth attendants; inadequate domestic and external funding; stock-outs of consumable inputs; and limited coverage of maternal and child health interventions. In order to accelerate progress towards MDGs 4 and 5, the Heads of State and Government recommended that countries should make maternal deaths notifiable and institutionalize maternal death audits; develop, fund and implement policies and strategies geared at improving maternal, newborn and child health; accelerate inter-sectoral action to address the broad health determinants; increase the number of skilled birth attendants; fulfil commitment to allocate at least 15% of the national budget to the health sector and allocate adequate resources to prevent stock-outs of essential medicines and reproductive health commodities; leverage health promotion approaches to raise national awareness; and ensure that there is a health centre within a radius of four kilometres equipped to provide good quality integrated maternal, newborn and child health services. Conclusions There was consensus among the discussants that there was urgent need to speed up actions for strengthening health systems to improve coverage of maternal, newborn and child health services; and to address broad determinants of women, newborn and children’s health for sustained improvements in health and other development goals. PMID:21810211

2011-01-01

151

Power module assembly  

DOEpatents

A power module assembly of the type suitable for deployment in a vehicular power inverter, wherein the power inverter has a grounded chassis, is provided. The power module assembly comprises a conductive base layer electrically coupled to the chassis, an insulating layer disposed on the conductive base layer, a first conductive node disposed on the insulating layer, a second conductive node disposed on the insulating layer, wherein the first and second conductive nodes are electrically isolated from each other. The power module assembly also comprises a first capacitor having a first electrode electrically connected to the conductive base layer, and a second electrode electrically connected to the first conductive node, and further comprises a second capacitor having a first electrode electrically connected to the conductive base layer, and a second electrode electrically connected to the second conductive node.

Campbell, Jeremy B. (Torrance, CA); Newson, Steve (Redondo Beach, CA)

2011-11-15

152

Liaison based assembly design  

SciTech Connect

Liaison Based Assembly Design extends the current information infrastructure to support design in terms of kinematic relationships between parts, or liaisons. These liaisons capture information regarding contact, degrees-of-freedom constraints and containment relationships between parts in an assembly. The project involved defining a useful collection of liaison representations, investigating their properties, and providing for maximum use of the data in downstream applications. We tested our ideas by implementing a prototype system involving extensions to Pro/Engineer and the Archimedes assembly planner. With an expanded product model, the design system is more able to capture design intent. When a product update is attempted, increased knowledge availability improves our ability to understand the effect of design changes. Manufacturing and analysis disciplines benefit from having liaison information available, so less time is wasted arguing over incomplete design specifications and our enterprise can be more completely integrated.

Ames, A.; Kholwadwala, D.; Wilson, R.H.

1996-12-01

153

International Space Station Carbon Dioxide Removal Assembly Testing  

NASA Technical Reports Server (NTRS)

Performance testing of the International Space Station Carbon Dioxide Removal Assembly flight hardware in the United States Laboratory during 1999 is described. The CDRA exceeded carbon dioxide performance specifications and operated flawlessly. Data from this test is presented.

Knox, James C.

2000-01-01

154

Low inductance connector assembly  

DOEpatents

A busbar connector assembly for coupling first and second terminals on a two-terminal device to first and second contacts on a power module is provided. The first terminal resides proximate the first contact and the second terminal resides proximate the second contact. The assembly comprises a first bridge having a first end configured to be electrically coupled to the first terminal, and a second end configured to be electrically coupled to the second contact, and a second bridge substantially overlapping the first bridge and having a first end electrically coupled to the first contact, and a second end electrically coupled to the second terminal.

Holbrook, Meghan Ann; Carlson, Douglas S

2013-07-09

155

Lightweight reflector assembly  

NASA Technical Reports Server (NTRS)

An inexpensive, lightweight reflective assembly member having good optical quality and particularly adaptable to accommodating temperature variations without providing destructive thermal stresses and reflective slope errors is described. The reflective assembly consists of a thin sheet of glass with appropriate reflective coating and a cellular glass block substrate bonded together. The method of fabrication includes abrading the cellular substrate with an abrasive master die to form an appropriate concave surface. An adhesive is applied to the abraded surface and a lamina reflective surface is placed under a uniform pressure to conform the reflective surface onto the desired abraded surface of the substrate.

Argoud, M. J.; Jolley, J.; Walker, W. L. (inventors)

1977-01-01

156

Modeling Self Assembly  

NSDL National Science Digital Library

This lesson, presented by the National Nanotechnology Infrastructure Network, covers self-assembly of molecules. Two activity are contained in this lesson. The first is "a hands-on modeling activity designed to introduce students to the area of nanotechnology and give them a basic understanding of how researchers build very small devices by the self-assembly of molecules." The second activity follows up on the first and gives "the students a chance to practice and demonstrate what they have learned." Two Teacher Preparation Guides and Two Student Guides are included. 

2014-08-26

157

Assembling an aesthetic.  

PubMed

Recent research informing and related to the study of three-dimensional scientific models is assembled here in a way that explores an aesthetic, specifically, of touch. I concentrate on the materiality of models, drawing on insights from the history and philosophy of science, design and metaphysics. This article chronicles the ways in which touch, or material interactions, operate in the world of 3D models, and its role in what models mean and do. I end with a call for greater attention to scientific process, described as assembly of and within science, which is revealed by this focus on touch. PMID:23176974

Candela, Emily

2012-12-01

158

OSIRIS-REx OCAMS detector assembly characterization  

NASA Astrophysics Data System (ADS)

The OSIRIS-REx asteroid sample return mission carries a suite of three cameras referred to as OCAMS. The Space Dynamics Laboratory (SDL) at Utah State University is providing the CCD-based detector assemblies for OCAMS to the Lunar Planetary Lab (LPL) at the University of Arizona. Working with the LPL, SDL has designed the electronics to operate a 1K by 1K frame transfer Teledyne DALSA Multi-Pinned Phase (MPP) CCD. The detector assembly electronics provides the CCD clocking, biasing, and digital interface with the OCAMS payload Command Control Module (CCM). A prototype system was built to verify the functionality of the detector assembly design and to characterize the detector system performance at the intended operating temperatures. The characterization results are described in this paper.

Hancock, J.; Crowther, B.; Whiteley, M.; Burt, R.; Watson, M.; Nelson, J.; Fellows, C.; Rizk, B.; Kinney-Spano, E.; Perry, M.; Hunten, M.

2013-09-01

159

Supramolecular Lego assembly towards three-dimensional multi-responsive hydrogels.  

PubMed

Inspired by the assembly of Lego toys, hydrogel building blocks with heterogeneous responsiveness are assembled utilizing macroscopic supramolecular recognition as the adhesion force. The Lego hydrogel provides 3D transformation upon pH variation. After disassembly of the building blocks by changing the oxidation state, they can be re-assembled into a completely new shape. PMID:24975743

Ma, Chunxin; Li, Tiefeng; Zhao, Qian; Yang, Xuxu; Wu, Jingjun; Luo, Yingwu; Xie, Tao

2014-08-27

160

Corner-cutting mining assembly  

DOEpatents

This invention resulted from a contract with the United States Department of Energy and relates to a mining tool. More particularly, the invention relates to an assembly capable of drilling a hole having a square cross-sectional shape with radiused corners. In mining operations in which conventional auger-type drills are used to form a series of parallel, cylindrical holes in a coal seam, a large amount of coal remains in place in the seam because the shape of the holes leaves thick webs between the holes. A higher percentage of coal can be mined from a seam by a means capable of drilling holes having a substantially square cross section. It is an object of this invention to provide an improved mining apparatus by means of which the amount of coal recovered from a seam deposit can be increased. Another object of the invention is to provide a drilling assembly which cuts corners in a hole having a circular cross section. These objects and other advantages are attained by a preferred embodiment of the invention.

Bradley, J.A.

1981-07-01

161

IFAS FACULTY ASSEMBLY MINUTESMINUTESMINUTESMINUTES  

E-print Network

to the Faculty Senate · B. Machen: Attempt to equalize the workload and have them understand the packets later. oIFAS FACULTY ASSEMBLY MINUTESMINUTESMINUTESMINUTES NOVEMBER 14, 2013 3:00 ­ 5:00 PM G001 MCCARTY D. BERNIE MACHEN · October 14th meeting at the faculty senate, Dr. Machen presented a proposal to add

Jawitz, James W.

162

Lageos assembly operation plan  

NASA Technical Reports Server (NTRS)

Guidelines and constraints procedures for LAGEOS assembly, operation, and design performance are given. Special attention was given to thermal, optical, and dynamic analysis and testing. The operation procedures illustrate the interrelation and sequence of tasks in a flow diagram. The diagram also includes quality assurance functions for verification of operation tasks.

Brueger, J.

1975-01-01

163

Corium protection assembly  

DOEpatents

A corium protection assembly includes a perforated base grid disposed below a pressure vessel containing a nuclear reactor core and spaced vertically above a containment vessel floor to define a sump therebetween. A plurality of layers of protective blocks are disposed on the grid for protecting the containment vessel floor from the corium.

Gou, Perng-Fei (Saratoga, CA); Townsend, Harold E. (Campbell, CA); Barbanti, Giancarlo (Sirtori, IT)

1994-01-01

164

Modeling Protein Self Assembly  

ERIC Educational Resources Information Center

Understanding the structure and function of proteins is an important part of the standards-based science curriculum. Proteins serve vital roles within the cell and malfunctions in protein self assembly are implicated in degenerative diseases. Experience indicates that this topic is a difficult one for many students. We have found that the concept…

Baker, William P.; Jones, Carleton Buck; Hull, Elizabeth

2004-01-01

165

Beyond the Assembly Line.  

ERIC Educational Resources Information Center

Describes how Hughes Aircraft trainers followed four steps in meeting the challenges of a flexible manufacturing environment: needs assessment, design strategy, pilot evaluation, and follow-through. Within this environment, 50 self-paced training products were developed for one of the company's wire and back plane harness assembly departments. (CT)

Weitz, Rebecca; Guild, Todd

1985-01-01

166

IFAS FACULTY ASSEMBLY MINUTESMINUTESMINUTESMINUTES  

E-print Network

to approve ASSEMBLY CHAIR REPORT ­ ART TEIXEIRA - Extension for TPS&P was approved by the faculty senate o supporters of IFAS T. Yoho - Look good on the house side, no major university wide budget cuts planned - Land Department Chair Working on a Ph.D. program o Agronomy Chair o Horticultural Sciences Chair o West Florida

Jawitz, James W.

167

The International Assembly.  

ERIC Educational Resources Information Center

Looks at the missions and goals of the International Assembly of the National Council of Teachers of English, a global multicultural network promoting communication and cooperation for international exchange of teaching practices, literature, literacy, curriculum development, and research in English. Suggests some criteria to look at when…

Gerlach, Jeanne Marcum, Ed.

2000-01-01

168

The European Assembly Worksheet  

Microsoft Academic Search

Assembly tasks are most common in industrialised countries. Even in highly automated and mechanised branches like the automotive, high or uniform load situations are common and result in high physical workload. In industrialised countries almost one-third of the total sick leave is due to musculo-skeletal complaints and disorders, which might result from poor ergonomic design. In order to tackle that

K. Schaub; G. Caragnano; B. Britzke; R. Bruder

2012-01-01

169

Assembling a primary cilium.  

PubMed

Cilia are evolutionarily conserved, membrane-bound, microtubular projections emanating from the cell surface. They are assembled on virtually all cell types in the human body, with very few exceptions, and several recent reviews have covered the topic in great detail. The cilium is assembled from mature (mother) centrioles or basal bodies, which serve to nucleate growth of axonemes that give rise to two structurally distinct variants, motile and nonmotile cilia. Whereas motile cilia are typically found in large bundles and beat synchronously to generate fluid flow, primary cilia (with the exception of those found at the embryonic node) are generally immotile and are found as solitary organelles. Remarkably, until recently, the primary cilium was considered a vestigial organelle without apparent biological function. However, research over the past decade has established that the primary cilium is capable of transducing essential signaling information from the extracellular milieu. Defects in the cilium, and the structure from which it arises, the basal body, have been shown to cause a spectrum of diseases, ranging from developmental defects to obesity, diabetes, and cancer. Many of these diseases, or ciliopathies, are manifested as genetic syndromes, such as Joubert syndrome, Bardet-Biedel (BBS), Meckel-Gruber (MKS), and Nephronophthisis (NPHP), illustrating the importance of understanding cilium structure and function and the mechanisms required for its assembly. This review focuses primarily on recent advances in our understanding of the regulatory controls governing the assembly and maintenance of the primary cilium. PMID:23747070

Kim, Sehyun; Dynlacht, Brian David

2013-08-01

170

Ran modulates spindle assembly by regulating a subset of TPX2 and Kid activities including Aurora A activation  

Microsoft Academic Search

Ran, a GTPase in the Ras superfamily, is proposed to be a spatial regulator of microtubule spindle assembly by maintaining key spindle assembly factors in an active state close to chromatin. RanGTP is hypothesized to maintain the spindle assembly factors in the active state by binding to importin ?, part of the nuclear transport receptor complex, thereby preventing the inhibitory

Nadia Trieselmann; Sheri Armstrong; Jennifer Rauw; Andrew Wilde

2003-01-01

171

HIV1 assembly in macrophages  

Microsoft Academic Search

The molecular mechanisms involved in the assembly of newly synthesized Human Immunodeficiency Virus (HIV) particles are poorly understood. Most of the work on HIV-1 assembly has been performed in T cells in which viral particle budding and assembly take place at the plasma membrane. In contrast, few studies have been performed on macrophages, the other major target of HIV-1. Infected

Philippe Benaroch; Elisabeth Billard; Raphaël Gaudin; Michael Schindler; Mabel Jouve

2010-01-01

172

A framework for geometric reasoning about tools in assembly  

SciTech Connect

When assembling a product, humans, robots, and other automation employ a variety of tools to manipulate, attach, and test parts and subassemblies. This paper proposes a framework lo represent and reason about geometric accessibility constraints for a wide variety of assembly tools. Central to the framework is a use volume encoding a minimum space that must be free in an assembly state to apply a given tool, and placement constraints on where that volume must be placed relative to the parts on which the tool acts. Determining whether a tool can be applied in a given assembly state is an instance of the FINDPLACE problem. In addition, we present more efficient methods lo integrate the framework into assembly planning. For tools that are applied either before or after their target parts are mated, one method preprocesses a single tool application for all possible states of assembly of a product. For tools applied after their target parts are mated, a complementary method guarantees polynomial-time assembly planning. We describe experiments with an initial implementation of the framework and a library of seven tools.

Wilson, R.H.

1995-12-31

173

An Assembly Funnel Makes Biomolecular Complex Assembly Efficient  

PubMed Central

Like protein folding and crystallization, the self-assembly of complexes is a fundamental form of biomolecular organization. While the number of methods for creating synthetic complexes is growing rapidly, most require empirical tuning of assembly conditions and/or produce low yields. We use coarse-grained simulations of the assembly kinetics of complexes to identify generic limitations on yields that arise because of the many simultaneous interactions allowed between the components and intermediates of a complex. Efficient assembly occurs when nucleation is fast and growth pathways are few, i.e. when there is an assembly “funnel”. For typical complexes, an assembly funnel occurs in a narrow window of conditions whose location is highly complex specific. However, by redesigning the components this window can be drastically broadened, so that complexes can form quickly across many conditions. The generality of this approach suggests assembly funnel design as a foundational strategy for robust biomolecular complex synthesis. PMID:25360818

Zenk, John; Schulman, Rebecca

2014-01-01

174

Desmosome assembly and dynamics  

PubMed Central

Desmosomes are intercellular junctions that anchor intermediate filaments to the plasma membrane, forming a supracellular scaffold that provides mechanical resilience to tissues. This anchoring function is accomplished by specialized members of the cadherin family and associated cytoskeletal linking proteins, which together form a highly organized membrane core flanked by mirror image cytoplasmic plaques. Due to the biochemical insolubility of desmosomes, the mechanisms that govern assembly of these components into a functional organelle remained elusive. Recently developed molecular reporters and live cell imaging approaches have provided powerful new tools to monitor this finely-tuned process in real time. Here we discuss studies that are beginning to decipher the machinery and regulation governing desmosome assembly and homeostasis in situ, and how these mechanisms are affected during disease pathogenesis. PMID:23891292

Nekrasova, Oxana; Green, Kathleen J.

2013-01-01

175

Hearing Aid Assembly  

NASA Technical Reports Server (NTRS)

Progress in hearing aids has come a long way. Yet despite such progress hearing aids are not the perfect answer to many hearing problems. Some adult ears cannot accommodate tightly fitting hearing aids. Mouth movements such as chewing, talking, and athletic or other active endeavors also lead to loosely fitting ear molds. It is well accepted that loosely fitting hearing aids are the cause of feedback noise. Since feedback noise is the most common complaint of hearing aid wearers it has been the subject of various patents. Herein a hearing aid assembly is provided eliminating feedback noise. The assembly includes the combination of a hearing aid with a headset developed to constrict feedback noise.

Grugel, Richard N. (Inventor)

2002-01-01

176

Infrared floodlight assembly  

DOEpatents

An infrared floodlight assembly (10) including a cast aluminum outer housing (11) defining a central chamber (15) therein. A floodlight (14), having a tungsten halogen lamp as the light source, is spacedly positioned within a heat conducting member (43) within chamber (15) such that the floodlight is securedly positioned in an aligned manner relative to the assembly's filter (35) and lens (12) components. The invention also includes venting means (51) to allow air passage between the interior of the member (43) and the adjacent chamber (15), as well as engagement means (85) for engaging a rear surface of the floodlight (14) to retain it firmly against an internal flange of the member (43). A reflector (61), capable of being compressed to allow insertion or removal, is located within the heat conducting member's interior between the floodlight (14) and filter (35) to reflect infrared radiation toward the filter (35) and spaced lens (12).

Wierzbicki, Julian J. (Peabody, MA); Chakrabarti, Kirti B. (Danvers, MA)

1987-09-22

177

Self-assembling cytotoxins.  

PubMed

Decanal and N-amino-N'-1-octylguanidine (AOG), combined at 28 microM each, mediated erythrocyte lysis within 80 minutes under physiological conditions. By contrast, no lysis was observed after 20 hours with either decanal (56 microM) or AOG (100 microM) alone. The pronounced synergism observed for these chemicals and similar reactive pairs of chemicals is due to the self-assembly of more cytotoxic hydrazones in situ. Decanal and AOG also exhibit synergistic activity against cultured human cells (HeLa) and bacteria (Escherichia coli J96). This synergism may be useful in the design of cytotoxins that would self-assemble selectively from nontoxic precursors within tumors, while sparing normal tissue. PMID:3523757

Rideout, D

1986-08-01

178

Low inductance busbar assembly  

SciTech Connect

A busbar assembly for electrically coupling first and second busbars to first and second contacts, respectively, on a power module is provided. The assembly comprises a first terminal integrally formed with the first busbar, a second terminal integrally formed with the second busbar and overlapping the first terminal, a first bridge electrode having a first tab electrically coupled to the first terminal and overlapping the first and second terminals, and a second tab electrically coupled to the first contact, a second bridge electrode having a third tab electrically coupled to the second terminal, and overlapping the first and second terminals and the first tab, and a fourth tab electrically coupled to the second contact, and a fastener configured to couple the first tab to the first terminal, and the third tab to the second terminal.

Holbrook, Meghan Ann (Manhattan Beach, CA)

2010-09-21

179

Turbine seal assembly  

DOEpatents

A seal assembly that limits gas leakage from a hot gas path to one or more disc cavities in a turbine engine. The seal assembly includes a seal apparatus that limits gas leakage from the hot gas path to a respective one of the disc cavities. The seal apparatus comprises a plurality of blade members rotatable with a blade structure. The blade members are associated with the blade structure and extend toward adjacent stationary components. Each blade member includes a leading edge and a trailing edge, the leading edge of each blade member being located circumferentially in front of the blade member's corresponding trailing edge in a direction of rotation of the turbine rotor. The blade members are arranged such that a space having a component in a circumferential direction is defined between adjacent circumferentially spaced blade members.

Little, David A.

2013-04-16

180

Pull rod assembly  

DOEpatents

A pull rod assembly comprising a pull rod having three peripheral grooves, a piston device including an adaptor ring and a seal ring, said piston device being mounted on the pull rod by a split ring retainer situated in one groove and extending into an interior groove in the adaptor and a resilient split ring retained in another groove and positioned to engage the piston device and to retain the seal on its adaptor.

Cioletti, Olisse C. (Pittsburgh, PA)

1990-01-01

181

Self-Assembling Cytotoxins  

Microsoft Academic Search

Decanal and N-amino-N'-1-octylguanidine (AOG), combined at 28 mu M each, mediated erythrocyte lysis within 80 minutes under physiological conditions. By contrast, no lysis was observed after 20 hours with either decanal (56 mu M) or AOG (100 mu M) alone. The pronounced synergism observed for these chemicals and similar reactive pairs of chemicals is due to the self-assembly of more

Darryl Rideout

1986-01-01

182

Combustor liner support assembly  

NASA Technical Reports Server (NTRS)

A support assembly for a gas turbine engine combustor includes an annular frame having a plurality of circumferentially spaced apart tenons, and an annular combustor liner disposed coaxially with the frame and including a plurality of circumferentially spaced apart tenons circumferentially adjoining respective ones of the frame tenons for radially and tangentially supporting the liner to the frame while allowing unrestrained differential thermal radial movement therebetween.

Halila, Ely E. (Inventor)

1994-01-01

183

Assembling a primary cilium  

PubMed Central

Summary Cilia are evolutionarily conserved, membrane-bound, microtubular projections emanating from the cell surface. They are assembled on virtually all cell types in the human body, with very few exceptions, and several recent reviews have covered the topic in great detail [1–3]. The cilium is assembled from mature (mother) centrioles or basal bodies, which serve to nucleate growth of axonemes that give rise to two structurally distinct variants, motile and non-motile cilia. Whereas motile cilia are typically found in large bundles and beat synchronously to generate fluid flow, primary cilia (with the exception of those found at the embryonic node) are generally immotile and are found as solitary organelles [3, 4]. Remarkably, until recently, the primary cilium was considered a vestigial organelle without apparent biological function. However, research over the past decade has established that the primary cilium is capable of transducing essential signaling information from the extracellular milieu [1, 5]. Defects in the cilium, and the structure from which it arises, the basal body, have been shown to cause a spectrum of diseases, ranging from developmental defects to obesity, diabetes, and cancer [6]. Many of these diseases, or ciliopathies, are manifested as genetic syndromes, such as Joubert syndrome, Bardet-Biedel (BBS), Meckel-Gruber (MKS), and Nephronophthisis (NPHP) [6], illustrating the importance of understanding cilium structure and function and the mechanisms required for its assembly. This review focuses primarily on recent advances in our understanding of the regulatory controls governing the assembly and maintenance of the primary cilium. PMID:23747070

Kim, Sehyun; Dynlacht, Brian David

2013-01-01

184

HSPES membrane electrode assembly  

NASA Technical Reports Server (NTRS)

An improved fuel cell electrode, as well as fuel cells and membrane electrode assemblies that include such an electrode, in which the electrode includes a backing layer having a sintered layer thereon, and a non-sintered free-catalyst layer. The invention also features a method of forming the electrode by sintering a backing material with a catalyst material and then applying a free-catalyst layer.

Kindler, Andrew (Inventor); Yen, Shiao-Ping (Inventor)

2000-01-01

185

In situ overlap and sequence synthesis during DNA assembly.  

PubMed

Modern cloning methods are independent from restriction enzyme recognition sites. However, nearly all current cloning methods still require the introduction of overlaps by PCR, which can introduce undesired mutations. Here, we investigated whether overlaps needed for DNA assembly can be synthesized in situ and we tested if the de novo synthesis of sequences can be simultaneously combined with the assembly of larger double-stranded DNA fragments. We showed in a set of 44 cloning experiments that overlaps of 20 bp needed for DNA assembly can be synthesized in situ from single-stranded oligonucleotides. Short sequences of 30-255 bp can be synthesized from single-stranded oligonucleotides concurrently with DNA assembly, and both techniques can be combined. The assembly of similar constructs by state-of-the-art techniques would have required multiple rounds of cloning or tedious sample preparations, whereas our approach is a one-step reaction. PMID:24161008

Paetzold, Bernhard; Carolis, Carlo; Ferrar, Tony; Serrano, Luis; Lluch-Senar, Maria

2013-12-20

186

Pathfinder aircraft being assembled - wing assembly  

NASA Technical Reports Server (NTRS)

Technicians easily lift a 20-foot-long wing section during assembly of the Pathfinder solar-powered research aircraft at NASA's Dryden Flight Research Center, Edwards, California. A number of upgrades were made to the unique aircraft prior to its successful checkout flight Nov. 19, 1996, among them the installation of stronger ultra-light wing ribs made of composite materials on two of the five wing panels. Pathfinder was a lightweight, solar-powered, remotely piloted flying wing aircraft used to demonstrate the use of solar power for long-duration, high-altitude flight. Its name denotes its mission as the 'Pathfinder' or first in a series of solar-powered aircraft that will be able to remain airborne for weeks or months on scientific sampling and imaging missions. Solar arrays covered most of the upper wing surface of the Pathfinder aircraft. These arrays provided up to 8,000 watts of power at high noon on a clear summer day. That power fed the aircraft's six electric motors as well as its avionics, communications, and other electrical systems. Pathfinder also had a backup battery system that could provide power for two to five hours, allowing for limited-duration flight after dark. Pathfinder flew at airspeeds of only 15 to 20 mph. Pitch control was maintained by using tiny elevators on the trailing edge of the wing while turns and yaw control were accomplished by slowing down or speeding up the motors on the outboard sections of the wing. On September 11, 1995, Pathfinder set a new altitude record for solar-powered aircraft of 50,567 feet above Edwards Air Force Base, California, on a 12-hour flight. On July 7, 1997, it set another, unofficial record of 71,500 feet at the Pacific Missile Range Facility, Kauai, Hawaii. In 1998, Pathfinder was modified into the longer-winged Pathfinder Plus configuration. (See the Pathfinder Plus photos and project description.)

1996-01-01

187

Self-assembly from milli- to nanoscales: methods and applications.  

PubMed

The design and fabrication techniques for microelectromechanical systems (MEMS) and nanodevices are progressing rapidly. However, due to material and process flow incompatibilities in the fabrication of sensors, actuators and electronic circuitry, a final packaging step is often necessary to integrate all components of a heterogeneous microsystem on a common substrate. Robotic pick-and-place, although accurate and reliable at larger scales, is a serial process that downscales unfavorably due to stiction problems, fragility and sheer number of components. Self-assembly, on the other hand, is parallel and can be used for device sizes ranging from millimeters to nanometers. In this review, the state-of-the-art in methods and applications for self-assembly is reviewed. Methods for assembling three-dimensional (3D) MEMS structures out of two-dimensional (2D) ones are described. The use of capillary forces for folding 2D plates into 3D structures, as well as assembling parts onto a common substrate or aggregating parts to each other into 2D or 3D structures, is discussed. Shape matching and guided assembly by magnetic forces and electric fields are also reviewed. Finally, colloidal self-assembly and DNA-based self-assembly, mainly used at the nanoscale, are surveyed, and aspects of theoretical modeling of stochastic assembly processes are discussed. PMID:20209016

Mastrangeli, M; Abbasi, S; Varel, C; Van Hoof, C; Celis, J-P; Böhringer, K F

2009-07-01

188

Spatially confined assembly of nanoparticles.  

PubMed

Conspectus The ability to assemble NPs into ordered structures that are expected to yield collective physical or chemical properties has afforded new and exciting opportunities in the field of nanotechnology. Among the various configurations of nanoparticle assemblies, two-dimensional (2D) NP patterns and one-dimensional (1D) NP arrays on surfaces are regarded as the ideal assembly configurations for many technological devices, for example, solar cells, magnetic memory, switching devices, and sensing devices, due to their unique transport phenomena and the cooperative properties of NPs in assemblies. To realize the potential applications of NP assemblies, especially in nanodevice-related applications, certain key issues must still be resolved, for example, ordering and alignment, manipulating and positioning in nanodevices, and multicomponent or hierarchical structures of NP assemblies for device integration. Additionally, the assembly of NPs with high precision and high levels of integration and uniformity for devices with scaled-down dimensions has become a key and challenging issue. Two-dimensional NP patterns and 1D NP arrays are obtained using traditional lithography techniques (top-down strategies) or interfacial assembly techniques (bottom-up strategies). However, a formidable challenge that persists is the controllable assembly of NPs in desired locations over large areas with high precision and high levels of integration. The difficulty of this assembly is due to the low efficiency of small features over large areas in lithography techniques or the inevitable structural defects that occur during the assembly process. The combination of self-assembly strategies with existing nanofabrication techniques could potentially provide effective and distinctive solutions for fabricating NPs with precise position control and high resolution. Furthermore, the synergistic combination of spatially mediated interactions between nanoparticles and prestructures on surfaces may play an increasingly important role in the controllable assembly of NPs. In this Account, we summarize our approaches and progress in fabricating spatially confined assemblies of NPs that allow for the positioning of NPs with high resolution and considerable throughput. The spatially selective assembly of NPs at the desired location can be achieved by various mechanisms, such as, a controlled dewetting process, electrostatically mediated assembly of particles, and confined deposition and growth of NPs. Three nanofabrication techniques used to produce prepatterns on a substrate are summarized: the Langmuir-Blodgett (LB) patterning technique, e-beam lithography (EBL), and nanoimprint lithography (NPL). The particle density, particle size, or interparticle distance in NP assemblies strongly depends on the geometric parameters of the template structure due to spatial confinement. In addition, with smart design template structures, multiplexed NPs can be assembled into a defined structure, thus demonstrating the structural and functional complexity required for highly integrated and multifunction applications. PMID:25244100

Jiang, Lin; Chen, Xiaodong; Lu, Nan; Chi, Lifeng

2014-10-21

189

On Constraints in Assembly Planning  

SciTech Connect

Constraints on assembly plans vary depending on product, assembly facility, assembly volume, and many other factors. Assembly costs and other measures to optimize vary just as widely. To be effective, computer-aided assembly planning systems must allow users to express the plan selection criteria that appIy to their products and production environments. We begin this article by surveying the types of user criteria, both constraints and quality measures, that have been accepted by assembly planning systems to date. The survey is organized along several dimensions, including strategic vs. tactical criteria; manufacturing requirements VS. requirements of the automated planning process itself and the information needed to assess compliance with each criterion. The latter strongly influences the efficiency of planning. We then focus on constraints. We describe a framework to support a wide variety of user constraints for intuitive and efficient assembly planning. Our framework expresses all constraints on a sequencing level, specifying orders and conditions on part mating operations in a number of ways. Constraints are implemented as simple procedures that either accept or reject assembly operations proposed by the planner. For efficiency, some constraints are supplemented with special-purpose modifications to the planner's algorithms. Fast replanning enables an interactive plan-view-constrain-replan cycle that aids in constraint discovery and documentation. We describe an implementation of the framework in a computer-aided assembly planning system and experiments applying the system to a number of complex assemblies, including one with 472 parts.

Calton, T.L.; Jones, R.E.; Wilson, R.H.

1998-12-17

190

Precision Robotic Assembly Machine  

ScienceCinema

The world's largest laser system is the National Ignition Facility (NIF), located at Lawrence Livermore National Laboratory. NIF's 192 laser beams are amplified to extremely high energy, and then focused onto a tiny target about the size of a BB, containing frozen hydrogen gas. The target must be perfectly machined to incredibly demanding specifications. The Laboratory's scientists and engineers have developed a device called the "Precision Robotic Assembly Machine" for this purpose. Its unique design won a prestigious R&D-100 award from R&D Magazine.

None

2010-09-01

191

Mitochondrial assembly in yeast.  

PubMed

The yeast Saccharomyces cerevisiae is likely to be the first organism for which a complete inventory of mitochondrial proteins and their functions can be drawn up. A survey of the 340 or so proteins currently known to be localised in yeast mitochondria reveals the considerable investment required to maintain the organelle's own genetic system, which itself contributes seven key components of the electron transport chain. Translation and respiratory complex assembly are particularly expensive processes, together requiring around 150 of the proteins so far known. Recent developments in both areas are reviewed and approaches to the identification of novel mitochondrial proteins are discussed. PMID:10376678

Grivell, L A; Artal-Sanz, M; Hakkaart, G; de Jong, L; Nijtmans, L G; van Oosterum, K; Siep, M; van der Spek, H

1999-06-01

192

Nuclear fuel assembly  

SciTech Connect

A fuel assembly for a nuclear reactor including a plurality of fuel rods held in spaced, parallel position between upper and lower tie plates and retained in lateral position by intermediate spacers and having a water tube in lieu of a fuel element in one or more of the rod positions, the water tubes having an outside diameter greater than that of the fuel rods and the spacer springs in the spacer cells of the water tubes being modified to accommodate the larger diameter of the water tubes.

Fanning, A.W.; Hazel, V.E.; Jameson, W.G.

1982-02-09

193

Liner mounting assembly  

NASA Technical Reports Server (NTRS)

A mounting assembly includes an annular supporting flange disposed coaxially about a centerline axis which has a plurality of circumferentially spaced apart supporting holes therethrough. An annular liner is disposed coaxially with the supporting flange and includes a plurality of circumferentially spaced apart mounting holes aligned with respective ones of the supporting holes. Each of a plurality of mounting pins includes a proximal end fixedly joined to the supporting flange through a respective one of the supporting holes, and a distal end disposed through a respective one of the liner mounting holes for supporting the liner to the supporting flange while unrestrained differential thermal movement of the liner relative to the supporting flange.

Halila, Ely E. (Inventor)

1994-01-01

194

Assembling the bacterial segrosome.  

PubMed

Genome segregation in prokaryotes is a highly ordered process that integrates with DNA replication, cytokinesis and other fundamental facets of the bacterial cell cycle. The segrosome is the nucleoprotein complex that mediates DNA segregation in bacteria, its assembly and organization is best understood for plasmid partition. The recent elucidation of structures of the ParB plasmid segregation protein bound to centromeric DNA, and of the tertiary structures of other segregation proteins, are key milestones in the path to deciphering the molecular basis of bacterial DNA segregation. PMID:16584885

Hayes, Finbarr; Barillà, Daniela

2006-05-01

195

Precision Robotic Assembly Machine  

SciTech Connect

The world's largest laser system is the National Ignition Facility (NIF), located at Lawrence Livermore National Laboratory. NIF's 192 laser beams are amplified to extremely high energy, and then focused onto a tiny target about the size of a BB, containing frozen hydrogen gas. The target must be perfectly machined to incredibly demanding specifications. The Laboratory's scientists and engineers have developed a device called the "Precision Robotic Assembly Machine" for this purpose. Its unique design won a prestigious R&D-100 award from R&D Magazine.

2009-08-14

196

Controlling plasmon coupling in biomolecule-linked metal nanoparticle assemblies  

NASA Astrophysics Data System (ADS)

Molecular control of plasmon coupling is investigated in biomolecule-linked nanoparticle assemblies in two-particle, small cluster, and extended network formats. The relationship between structure and optical properties is explored through comparison of measured spectra with simulated spectra calculated using structural models based upon measured structural parameters. A variety of techniques are used to characterize nanoparticle assemblies, including ensemble extinction and elastic scattering spectroscopy, single-assembly scattering spectroscopy, transmission electron microscopy, and dynamic light scattering. Initially, molecular control of plasmon coupling is investigated in ˜100 nm assemblies composed of 13 nm gold "satellite" particles tethered by duplex DNA to a 50 nm gold "core" particle. Comparison of core-satellite assemblies formed with duplex DNA tethers of varying length demonstrates that, while core-satellite separation is controlled by the number of base pairs in the DNA tether, structural properties such as core:satellite ratio and yield are independent of DNA tether length. Thus, plasmon coupling within these assemblies is determined by the number of base pairs in the duplex DNA tether; compact assemblies in which tethers are composed of fewer base pairs exhibit plasmon bands that are red-shifted relative to the bands of extended assemblies, indicating increased plasmon coupling in the compact assemblies. Subsequently, core-satellite assemblies are formed with reconfigurable DNA nanostructure tethers that modulate interparticle separation in response to a molecular stimulus. Assembly reconfiguration from a compact to an extended state results in blue-shifting of the assembly plasmon resonance, indicating reduced interparticle coupling and lengthening of the core-satellite tether. Comparison between measured and simulated spectra revealed a close correspondence and provided validation of the structural models that link assembly plasmonic properties with DNA control of interparticle separation. Plasmon coupling is investigated also in binary metal systems. A new method for forming stable oligonucleotide-silver conjugates is presented, and controlled plasmon coupling is observed in reconfigurable core-satellite assemblies composed of 20 nm silver satellites linked to a 50 nm gold core by DNA tethers. Reconfiguration of the DNA linkers from a compact to an extended state results in decreased plasmon coupling and a blue-shift of the gold core plasmon resonance, similar to the response observed in analogous structures formed with gold satellites. Simulations of structures composed of gold and silver cores and satellites are performed to determine how the optical properties of binary metal assemblies may differ from those composed of a single metal. It appears that gold plasmons are systematically red shifted by silver particles, whereas plasmons supported by silver particles appear differentially sensitive to gold particles according to whether the silver particle is in a core position or a satellite shell. Next, the plasmonic properties of immobilized binary nanoparticle assemblies that incorporate a single strongly scattering component that acts as a template for assembly of weakly scattering plasmonic particles are investigated. Assemblies are composed of a streptavidin-coated gold "core" nanoparticle and BSA-biotin-coated gold or silver "satellite" particles. Through correlation of measured and simulated spectra, the dependence of assembly optical properties upon satellite coverage and satellite orientation about the core is addressed. It appears that plasmon coupling in gold core-gold satellite structures depends upon satellite orientation about the core and can manifest as either peak shifting or peak splitting, while the gold plasmon response to silver satellite assembly appears to be independent of satellite orientation. Finally, binary coupling is studied in one-dimensional particle pairs and three-dimensional extended networks composed of gold and silver particl

Sebba, David S.

197

Parallel De Bruijn Graph Construction and Traversal for De Novo Genome Assembly  

E-print Network

biomedical model and agricultural species. Meraculous [1] is a state-of-the-art de novo assembler for short, a state- of-the-art production assembler. First, we present a new par- allel algorithm for k-mer analysis sequences in species for which reference genomes do not exist. This advantage, however, comes at a cost

California at Berkeley, University of

198

Microchannel heat sink assembly  

DOEpatents

The present invention provides a microchannel heat sink with a thermal range from cryogenic temperatures to several hundred degrees centigrade. The heat sink can be used with a variety of fluids, such as cryogenic or corrosive fluids, and can be operated at a high pressure. The heat sink comprises a microchannel layer preferably formed of silicon, and a manifold layer preferably formed of glass. The manifold layer comprises an inlet groove and outlet groove which define an inlet manifold and an outlet manifold. The inlet manifold delivers coolant to the inlet section of the microchannels, and the outlet manifold receives coolant from the outlet section of the microchannels. In one embodiment, the manifold layer comprises an inlet hole extending through the manifold layer to the inlet manifold, and an outlet hole extending through the manifold layer to the outlet manifold. Coolant is supplied to the heat sink through a conduit assembly connected to the heat sink. A resilient seal, such as a gasket or an O-ring, is disposed between the conduit and the hole in the heat sink in order to provide a watertight seal. In other embodiments, the conduit assembly may comprise a metal tube which is connected to the heat sink by a soft solder. In still other embodiments, the heat sink may comprise inlet and outlet nipples. The present invention has application in supercomputers, integrated circuits and other electronic devices, and is suitable for cooling materials to superconducting temperatures. 13 figs.

Bonde, W.L.; Contolini, R.J.

1992-03-24

199

Measuring electrode assembly  

DOEpatents

A pH measuring electrode assembly for immersion in a solution includes an enclosed cylindrical member having an aperture at a lower end thereof. An electrolyte is located in the cylindrical member above the level of the aperture and an electrode is disposed in this electrolyte. A ring formed of an ion porous material is mounted relative to the cylindrical member so that a portion of this ring is rotatable relative to and is covering the aperture in the cylindrical member. A suitable mechanism is also provided for indicating which one of a plurality of portions of the ring is covering the aperture and to keep track of which portions of the ring have already been used and become clogged. Preferably, the electrode assembly also includes a glass electrode member in the center thereof including a second electrolyte and electrode disposed therein. The cylindrical member is resiliently mounted relative to the glass electrode member to provide for easy rotation of the cylindrical member relative to the glass electrode member for changing of the portion of the ring covering the aperture.

Bordenick, John E. (West Mifflin, PA)

1989-01-01

200

Microchannel heat sink assembly  

DOEpatents

The present invention provides a microchannel heat sink with a thermal range from cryogenic temperatures to several hundred degrees centigrade. The heat sink can be used with a variety of fluids, such as cryogenic or corrosive fluids, and can be operated at a high pressure. The heat sink comprises a microchannel layer preferably formed of silicon, and a manifold layer preferably formed of glass. The manifold layer comprises an inlet groove and outlet groove which define an inlet manifold and an outlet manifold. The inlet manifold delivers coolant to the inlet section of the microchannels, and the outlet manifold receives coolant from the outlet section of the microchannels. In one embodiment, the manifold layer comprises an inlet hole extending through the manifold layer to the inlet manifold, and an outlet hole extending through the manifold layer to the outlet manifold. Coolant is supplied to the heat sink through a conduit assembly connected to the heat sink. A resilient seal, such as a gasket or an O-ring, is disposed between the conduit and the hole in the heat sink in order to provide a watetight seal. In other embodiments, the conduit assembly may comprise a metal tube which is connected to the heat sink by a soft solder. In still other embodiments, the heat sink may comprise inlet and outlet nipples. The present invention has application in supercomputers, integrated circuits and other electronic devices, and is suitable for cooling materials to superconducting temperatures.

Bonde, Wayne L. (Livermore, CA); Contolini, Robert J. (Pleasanton, CA)

1992-01-01

201

Measuring electrode assembly  

DOEpatents

A pH measuring electrode assembly for immersion in a solution includes an enclosed cylindrical member having an aperture at a lower end thereof. An electrolyte is located in the cylindrical member above the level of the aperture and an electrode is disposed in this electrolyte. A ring formed of an ion porous material is mounted relative to the cylindrical member so that a portion of this ring is rotatable relative to and is covering the aperture in the cylindrical member. A suitable mechanism is also provided for indicating which one of a plurality of portions of the ring is covering the aperture and to keep track of which portions of the ring have already been used and become clogged. Preferably, the electrode assembly also includes a glass electrode member in the center thereof including a second electrolyte and electrode disposed therein. The cylindrical member is resiliently mounted relative to the glass electrode member to provide for easy rotation of the cylindrical member relative to the glass electrode member for changing of the portion of the ring covering the aperture. 2 figs.

Bordenick, J.E.

1988-04-26

202

Gas separation membrane module assembly  

DOEpatents

A gas-separation membrane module assembly and a gas-separation process using the assembly. The assembly includes a set of tubes, each containing gas-separation membranes, arranged within a housing. The housing contains a tube sheet that divides the space within the housing into two gas-tight spaces. A permeate collection system within the housing gathers permeate gas from the tubes for discharge from the housing.

Wynn, Nicholas P (Palo Alto, CA); Fulton, Donald A. (Fairfield, CA)

2009-03-31

203

Great Basin Center for Geothermal Energy Proposal for DOE Geothermal Funding for Research to Increase Utilization of Geothermal Resources in the Western United States Assembly of a Crustal Seismic Velocity Database for the Western Great Basin  

Microsoft Academic Search

This project will assemble a three-dimensional reference seismic velocity model for the western Great Basin region of Nevada and eastern California. Exploration for hidden resources requires a realistic three-dimensional crustal model to understand the deep sources of geothermal heat in the crust. The type of rule-based representations developed by the Southern California Earthquake Center (SCEC) are very appropriate to defining

John N. Louie

204

Airfoil nozzle and shroud assembly  

DOEpatents

An airfoil and nozzle assembly are disclosed including an outer shroud having a plurality of vane members attached to an inner surface and having a cantilevered end. The assembly further includes a inner shroud being formed by a plurality of segments. Each of the segments having a first end and a second end and having a recess positioned in each of the ends. The cantilevered end of the vane member being positioned in the recess. The airfoil and nozzle assembly being made from a material having a lower rate of thermal expansion than that of the components to which the airfoil and nozzle assembly is attached. 5 figs.

Shaffer, J.E.; Norton, P.F.

1997-06-03

205

Airfoil nozzle and shroud assembly  

DOEpatents

An airfoil and nozzle assembly including an outer shroud having a plurality of vane members attached to an inner surface and having a cantilevered end. The assembly further includes a inner shroud being formed by a plurality of segments. Each of the segments having a first end and a second end and having a recess positioned in each of the ends. The cantilevered end of the vane member being positioned in the recess. The airfoil and nozzle assembly being made from a material having a lower rate of thermal expansion than that of the components to which the airfoil and nozzle assembly is attached.

Shaffer, James E. (Maitland, FL); Norton, Paul F. (San Diego, CA)

1997-01-01

206

Multi-position photovoltaic assembly  

DOEpatents

The invention is directed to a PV assembly, for use on a support surface, comprising a base, a PV module, a multi-position module support assembly, securing the module to the base at shipping and inclined-use angles, a deflector, a multi-position deflector support securing the deflector to the base at deflector shipping and deflector inclined-use angles, the module and deflector having opposed edges defining a gap therebetween. The invention permits transport of the PV assemblies in a relatively compact form, thus lowering shipping costs, while facilitating installation of the PV assemblies with the PV module at the proper inclination.

Dinwoodie, Thomas L. (Piedmont, CA)

2003-03-18

207

Automated precision assembly through neurovision  

NASA Astrophysics Data System (ADS)

In this study an intelligent control architecture is proposed for recognition and diagnosis of digital images captured by the vision system to control the robot manipulator in automated precision assembly. The architecture proposed provides enough flexibility to the assembly cell in processing a wide variety of products that require precision assembly. The system uses ART paradigm for part recognition and backpropagation for calibration. System architecture is tested using an IBM 7547 robot with a CCD camera for precision assembly of a printed circuit board (PCB) and satisfactory results are obtained.

Vellanki, Mahesh K.; Dagli, Cihan H.

1992-09-01

208

Next-generation transcriptome assembly  

SciTech Connect

Transcriptomics studies often rely on partial reference transcriptomes that fail to capture the full catalog of transcripts and their variations. Recent advances in sequencing technologies and assembly algorithms have facilitated the reconstruction of the entire transcriptome by deep RNA sequencing (RNA-seq), even without a reference genome. However, transcriptome assembly from billions of RNA-seq reads, which are often very short, poses a significant informatics challenge. This Review summarizes the recent developments in transcriptome assembly approaches - reference-based, de novo and combined strategies-along with some perspectives on transcriptome assembly in the near future.

Martin, Jeffrey A.; Wang, Zhong

2011-09-01

209

Supramolecular Assembly of Biohybrid Photoconversion Systems  

SciTech Connect

Self-assembled membrane architectures have great potential for the development of materials for the conversion of solar energy into electricity or fuels. Discovering the design principles that promote self-assembly in natural photosynthetic systems may provide inspiration for the development of synthetic solar conversion systems. We report for the first time that naturally occurring light harvesting antennae can alter the phase behavior of a poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) (PEO-PPO-PEO) block copolymer system from micellar to lamellar structures mimicking their role in maintaining the supramolecular architecture of the photosynthetic membrane. Small-angle neutron scattering shows that PEO{sub 43}-PPO{sub 16}-PEO{sub 43} micelles undergo a phase transition from a micellar state to a lamellar structure with a {approx}60 {angstrom} spatial repetition in the presence of plant light harvesting complex II (LHCII). In addition, spectrophotometric analysis indicates that the protein self-assembles in the synthetic membrane structure. Photodependent hydrogen production mediated by LHCII embedded in the block copolymer had a maximum rate of 6.4 {micro}mol h{sup -1} per mg chlorophyll. The production of H{sub 2} was sustained for greater than 100 hours showing the potential of this approach for the development of self-assembled bioinspired photoconversion systems. Although excited energy transfer is the primary function of LHCII, this work provides evidence that the protein complex can also perform electron transfer, a role not known to occur in vivo. The significance of this work is that it provides a novel approach for developing a new class of membrane-based smart material with a well-controlled architecture that is dependent on the assembly of interacting components, and it could also have important implications in self-repair and control of energy transfer in photoconversion devices.

Cardoso, Mateus B [ORNL; Smolensky, Dmitriy [ORNL; Heller, William T [ORNL; Hong, Kunlun [ORNL; O'Neill, Hugh Michael [ORNL

2011-01-01

210

32 CFR 644.104 - Procurement of deed and title assembly.  

Code of Federal Regulations, 2011 CFR

...Acquisition Involuntary Acquisition by the United States § 644.104 Procurement of deed and title assembly. In any case in which the Court determines that the United States has taken an interest in real...

2011-07-01

211

32 CFR 644.104 - Procurement of deed and title assembly.  

Code of Federal Regulations, 2013 CFR

...Acquisition Involuntary Acquisition by the United States § 644.104 Procurement of deed and title assembly. In any case in which the Court determines that the United States has taken an interest in real...

2013-07-01

212

32 CFR 644.104 - Procurement of deed and title assembly.  

Code of Federal Regulations, 2012 CFR

...Acquisition Involuntary Acquisition by the United States § 644.104 Procurement of deed and title assembly. In any case in which the Court determines that the United States has taken an interest in real...

2012-07-01

213

Method and apparatus for assembling a permanent magnet pole assembly  

DOEpatents

A pole assembly for a rotor, the pole assembly includes a permanent magnet pole including at least one permanent magnet block, a plurality of laminations including a pole cap mechanically coupled to the pole, and a plurality of laminations including a base plate mechanically coupled to the pole.

Carl, Jr., Ralph James (Clifton Park, NY); Bagepalli, Bharat Sampathkumaran (Niskayuna, NY); Jansen, Patrick Lee (Scotia, NY); Dawson, Richard Nils (Voorheesville, NY); Qu, Ronghai (Clifton Park, NY); Avanesov, Mikhail Avramovich (Moscow, RU)

2009-08-11

214

Clean then Assemble Versus Assemble then Clean: Several Comparisons  

NASA Technical Reports Server (NTRS)

Cleanliness of manufactured parts and assemblies is a significant issue in many industries including disk drives, semiconductors, aerospace, and medical devices. Clean manufacturing requires cleanroom floor space and cleaning technology that are both expensive to own and expensive to operate. Strategies to reduce these costs are an important consideration. One strategy shown to be effective at reducing costs is to assemble parts into subassemblies and then clean the subassembly, rather than clean the individual parts first and then assemble them. One advantage is that assembly outside of the cleanroom reduces the amount of cleanroom floor space and its associated operating cost premium. A second advantage is that this strategy reduces the number of individual parts that must be cleaned prior to assembly, reducing the number of cleaning baskets, handling and, possibly, reducing the number of cleaners. The assemble then clean strategy also results in a part that is significantly cleaner because contamination generated during the assembly steps are more effectively removed that normally can be achieved by hand wiping after assembly in the cleanroom.

Welker, Roger W.

2004-01-01

215

Flexible cloth seal assembly  

DOEpatents

A seal assembly is described having a flexible cloth seal which includes a shim assemblage surrounded by a cloth assemblage. A first tubular end portion, such as a gas turbine combustor, includes a longitudinal axis and has smooth and spaced-apart first and second surface portions defining a notch there between which is wider at its top than at its bottom and which extends outward from the axis. The second surface portion is outside curved, and a first edge of the cloth seal is positioned in the bottom of the notch. A second tubular end portion, such as a first stage nozzle, is located near, spaced apart from, and coaxially aligned with, the first tubular end portion. The second tubular end portion has a smooth third surface portion which surrounds at least a portion of the first tubular end portion and which is contacted by the cloth seal. 7 figs.

Bagepalli, B.S.; Taura, J.C.; Aksit, M.F.; Demiroglu, M.; Predmore, D.R.

1999-06-29

216

Photovoltaic cell assembly  

DOEpatents

A photovoltaic assembly for converting high intensity solar radiation into lectrical energy in which a solar cell is separated from a heat sink by a thin layer of a composite material which has excellent dielectric properties and good thermal conductivity. This composite material is a thin film of porous Al.sub.2 O.sub.3 in which the pores have been substantially filled with an electrophoretically-deposited layer of a styrene-acrylate resin. This composite provides electrical breakdown strengths greater than that of a layer consisting essentially of Al.sub.2 O.sub.3 and has a higher thermal conductivity than a layer of styrene-acrylate alone.

Beavis, Leonard C. (Albuquerque, NM); Panitz, Janda K. G. (Edgewood, NM); Sharp, Donald J. (Albuquerque, NM)

1990-01-01

217

Rotatable seal assembly  

DOEpatents

An assembly is provided for rotatably supporting a rotor on a stator so that vacuum chambers in the rotor and stator remain in communication while the chambers are sealed from ambient air, which enables the use of a ball bearing or the like to support most of the weight of the rotor. The apparatus includes a seal device mounted on the rotor to rotate therewith, but shiftable in position on the rotor while being sealed to the rotor as by an O-ring. The seal device has a flat face that is biased towards a flat face on the stator, and pressurized air is pumped between the faces to prevent contact between them while spacing them a small distance apart to avoid the inflow of large amounts of air between the faces and into the vacuum chambers.

Logan, Clinton M. (Pleasanton, CA); Garibaldi, Jack L. (Livermore, CA)

1982-01-01

218

Assembly sequencing with toleranced parts  

SciTech Connect

The goal of assembly sequencing is to plan a feasible series of operations to construct a product from its individual parts. Previous research has thoroughly investigated assembly sequencing under the assumption that parts have nominal geometry. This paper considers the case where parts have toleranced geometry. Its main contribution is an efficient procedure that decides if a product admits an assembly sequence with infinite translations that is feasible for all possible instances of the components within the specified tolerances. If the product admits one such sequence, the procedure can also generate it. For the cases where there exists no such assembly sequence, another procedure is proposed which generates assembly sequences that are feasible only for some values of the toleranced dimensions. If this procedure produces no such sequence, then no instance of the product is assemblable. Finally, this paper analyzes the relation between assembly and disassembly sequences in the presence of toleranced parts. This work assumes a simple, but non-trivial tolerance language that falls short of capturing all imperfections of a manufacturing process. Hence, it is only one step toward assembly sequencing with toleranced parts.

Latombe, J.C. [Stanford Univ., CA (United States). Robotics Lab.; Wilson, R.H. [Sandia National Labs., Albuquerque, NM (United States). Intelligent Systems and Robotics Center

1995-02-21

219

Space assembled entry systems certification  

NASA Technical Reports Server (NTRS)

The approach taken to the issue, that 'How do you say you're 'good for go' if you space assemble an entry vehicle?', are: (1) shuttle orbiter thermal protection certification; (2) shuttle thermal protection system flight experience; and (3) space assembled entry system certification.

Curry, Donald M.

1993-01-01

220

Moisture Research - Optimizing Wall Assemblies  

SciTech Connect

The Consortium for Advanced Residential Buildings (CARB) evaluated several different configurations of wall assemblies to determine the accuracy of moisture modeling and make recommendations to ensure durable, efficient assemblies. WUFI and THERM were used to model the hygrothermal and heat transfer characteristics of these walls.

Arena, L.; Mantha, P.

2013-05-01

221

A Virtual Assembly Design Environment  

Microsoft Academic Search

The Virtual Assembly Design Environment (VADE) is a Virtual Reality (VR)-based engineering application that allows engineers to evaluate, analyze, and plan the assembly of mechanical systems. This system focuses on utilizing an immersive, virtual environment tightly coupled with commercial computer aided design (CAD) systems. Salient features of VADE include: 1) data integration (two-way) with a parametric CAD system, 2) realistic

Sankar Jayaram; Yong Wang; Uma Jayaram; Kevin W. Lyons; Peter Hart

1999-01-01

222

Solar energy collecting panel assembly  

Microsoft Academic Search

A solar energy collector is disclosed having panel assemblies for absorbing solar energy and transferring heat to moving air. Each panel assembly has a heat insulated housing carrying a plurality of side-by-side solar energy collector units. Each unit has a base plate carrying upwardly directed longitudinal ribs providing solar energy collector surfaces and downwardly directed longitudinal fins providing heat dissipating

1981-01-01

223

Assembly strategies for chamferless parts  

Microsoft Academic Search

The authors illustrate the need for planning in assembly and describe a set of modeling and planning techniques developed to generate robust force-control strategies for a certain class of assemblies. Specifically, they develop strategies for the chamferless insertion of a planar peg into a hole and the insertion of a three-dimensional rectangular peg into a rectangular hole. The complexity of

Michael E. Caine; T. Lozano-Perez; W. P. Seering

1989-01-01

224

GCRE CRITICAL-ASSEMBLY STUDIES  

Microsoft Academic Search

Critical-assembly studies were made to provide engineering and physics ; data to aid in developing the Gas Cooled Reactor Experiment-1 (GCRE-l). ; Measurements of critical mass, flux and power distributions, and shutdown worth ; of the GCRE-1 mock-up safety and control blades were obtained. The critical ; assembly consists of aluminum tubes containing four concentric stainless steel ; cylinders wrapped

D. A. Dingee; W. C. Ballowe; R. W. Klingensmith; R. A. Egen; F. J. Jankowski; J. W. Chastain

1958-01-01

225

Three dimensional colorimetric assay assemblies  

DOEpatents

A direct assay is described using novel three-dimensional polymeric assemblies which change from a blue to red color when exposed to an analyte, in one case a flu virus. The assemblies are typically in the form of liposomes which can be maintained in a suspension, and show great intensity in their color changes. Their method of production is also described.

Charych, Deborah (Albany, CA); Reichart, Anke (Albany, CA)

2000-01-01

226

Three dimensional colorimetric assay assemblies  

SciTech Connect

A direct assay is described using novel three-dimensional polymeric assemblies which change from a blue to red color when exposed to an analyte, in one case a flu virus. The assemblies are typically in the form of liposomes which can be maintained in a suspension, and show great intensity in their color changes. Their method of production is also described.

Charych, D.; Reichart, A.

2000-06-27

227

Assembly Language Tools User's Guide  

E-print Network

or relating to any combination, machine, or process in which such products or services might be or are usedTMS320C55x Assembly Language Tools User's Guide Literature Number: SPRU280D June 2001 Printed Incorporated #12;iii Preface Read This First About This Manual The TMS320C55x Assembly Language Tools User

Reisslein, Martin

228

Locking Centrifuge Rotor Cover Assembly  

Microsoft Academic Search

A centrifuge rotor cover assembly for use with a centrifuge having a rotor and a housing enclosing the rotor and including a lid movable between a closed position overlying the rotor and an open position providing access to the rotor. The cover assembly includes a rotor cover removably coupled to the lid. Means are provided for engaging the rotor cover

Benjamin Linder; Don Lee; Amy Battles; David M. Otten

2000-01-01

229

Small Angle X-Ray Scattering Studies of Mitochondrial Glutaminase C Reveal Extended Flexible Regions, and Link Oligomeric State with Enzyme Activity  

PubMed Central

Glutaminase C is a key metabolic enzyme, which is unregulated in many cancer systems and believed to play a central role in the Warburg effect, whereby cancer cells undergo changes to an altered metabolic profile. A long-standing hypothesis links enzymatic activity to the protein oligomeric state, hence the study of the solution behavior in general and the oligomer state in particular of glutaminase C is important for the understanding of the mechanism of protein activation and inhibition. In this report, this is extensively investigated in correlation to enzyme concentration or phosphate level, using a high-throughput microfluidic-mixing chip for the SAXS data collection, and we confirm that the oligomeric state correlates with activity. The in-depth solution behavior analysis further reveals the structural behavior of flexible regions of the protein in the dimeric, tetrameric and octameric state and investigates the C-terminal influence on the enzyme solution behavior. Our data enable SAXS-based rigid body modeling of the full-length tetramer states, thereby presenting the first ever experimentally derived structural model of mitochondrial glutaminase C including the N- and C-termini of the enzyme. PMID:24098668

Møller, Magda; Nielsen, Søren S.; Ramachandran, Sekar; Li, Yuxing; Tria, Giancarlo; Streicher, Werner; Petoukhov, Maxim V.; Cerione, Richard A.; Gillilan, Richard E.; Vestergaard, Bente

2013-01-01

230

Advanced gray rod control assembly  

DOEpatents

An advanced gray rod control assembly (GRCA) for a nuclear reactor. The GRCA provides controlled insertion of gray rod assemblies into the reactor, thereby controlling the rate of power produced by the reactor and providing reactivity control at full power. Each gray rod assembly includes an elongated tubular member, a primary neutron-absorber disposed within the tubular member said neutron-absorber comprising an absorber material, preferably tungsten, having a 2200 m/s neutron absorption microscopic capture cross-section of from 10 to 30 barns. An internal support tube can be positioned between the primary absorber and the tubular member as a secondary absorber to enhance neutron absorption, absorber depletion, assembly weight, and assembly heat transfer characteristics.

Drudy, Keith J; Carlson, William R; Conner, Michael E; Goldenfield, Mark; Hone, Michael J; Long, Jr., Carroll J; Parkinson, Jerod; Pomirleanu, Radu O

2013-09-17

231

Assembly of surface engineered nanoparticles for functional materials  

NASA Astrophysics Data System (ADS)

Nanoparticles are regarded as exciting new building blocks for functional materials due to their fascinating physical properties because of the nano-confinement. Organizing nanoparticles into ordered hierarchical structures are highly desired for constructing novel optical and electrical artificial materials that are different from their isolated state or thermodynamics random ensembles. My research integrates the surface chemistry of nanoparticles, interfacial assembly and lithography techniques to construct nanoparticle based functional structures. We designed and synthesized tailor-made ligands for gold, semiconductor and magnetic nanoparticle, to modulate the assembly process and collective properties of the assembled structures, by controlling the key parameters such as particle-interface interaction, dielectric environments and inter-particle coupling etc. Top-down technologies such as micro contact printing, photolithography and nanoimprint lithography are used to guide the assembly into arbitrarily predesigned structures for potential device applications.

Yu, Xi

232

AND/OR graph representation of assembly plans  

NASA Technical Reports Server (NTRS)

A compact representation of all possible assembly plans of a product using AND/OR graphs is presented as a basis for efficient planning algorithms that allow an intelligent robot to pick a course of action according to instantaneous conditions. The AND/OR graph is equivalent to a state transition graph but requires fewer nodes and simplifies the search for feasible plans. Three applications are discussed: (1) the preselection of the best assembly plan, (2) the recovery from execution errors, and (3) the opportunistic scheduling of tasks. An example of an assembly with four parts illustrates the use of the AND/OR graph representation in assembly-plan preselection, based on the weighting of operations according to complexity of manipulation and stability of subassemblies. A hypothetical error situation is discussed to show how a bottom-up search of the AND/OR graph leads to an efficient recovery.

Homem De Mello, Luiz S.; Sanderson, Arthur C.

1990-01-01

233

De novo assembly of highly diverse viral populations  

PubMed Central

Background Extensive genetic diversity in viral populations within infected hosts and the divergence of variants from existing reference genomes impede the analysis of deep viral sequencing data. A de novo population consensus assembly is valuable both as a single linear representation of the population and as a backbone on which intra-host variants can be accurately mapped. The availability of consensus assemblies and robustly mapped variants are crucial to the genetic study of viral disease progression, transmission dynamics, and viral evolution. Existing de novo assembly techniques fail to robustly assemble ultra-deep sequence data from genetically heterogeneous populations such as viruses into full-length genomes due to the presence of extensive genetic variability, contaminants, and variable sequence coverage. Results We present VICUNA, a de novo assembly algorithm suitable for generating consensus assemblies from genetically heterogeneous populations. We demonstrate its effectiveness on Dengue, Human Immunodeficiency and West Nile viral populations, representing a range of intra-host diversity. Compared to state-of-the-art assemblers designed for haploid or diploid systems, VICUNA recovers full-length consensus and captures insertion/deletion polymorphisms in diverse samples. Final assemblies maintain a high base calling accuracy. VICUNA program is publicly available at: http://www.broadinstitute.org/scientific-community/science/projects/viral-genomics/ viral-genomics-analysis-software. Conclusions We developed VICUNA, a publicly available software tool, that enables consensus assembly of ultra-deep sequence derived from diverse viral populations. While VICUNA was developed for the analysis of viral populations, its application to other heterogeneous sequence data sets such as metagenomic or tumor cell population samples may prove beneficial in these fields of research. PMID:22974120

2012-01-01

234

Building polyhedra by self-assembly: theory and experiment.  

PubMed

Abstract We investigate the utility of a mathematical framework based on discrete geometry to model biological and synthetic self-assembly. Our primary biological example is the self-assembly of icosahedral viruses; our synthetic example is surface-tension-driven self-folding polyhedra. In both instances, the process of self-assembly is modeled by decomposing the polyhedron into a set of partially formed intermediate states. The set of all intermediates is called the configuration space, pathways of assembly are modeled as paths in the configuration space, and the kinetics and yield of assembly are modeled by rate equations, Markov chains, or cost functions on the configuration space. We review an interesting interplay between biological function and mathematical structure in viruses in light of this framework. We discuss in particular: (i) tiling theory as a coarse-grained description of all-atom models; (ii) the building game-a growth model for the formation of polyhedra; and (iii) the application of these models to the self-assembly of the bacteriophage MS2. We then use a similar framework to model self-folding polyhedra. We use a discrete folding algorithm to compute a configuration space that idealizes surface-tension-driven self-folding and analyze pathways of assembly and dominant intermediates. These computations are then compared with experimental observations of a self-folding dodecahedron with side 300 ?m. In both models, despite a combinatorial explosion in the size of the configuration space, a few pathways and intermediates dominate self-assembly. For self-folding polyhedra, the dominant intermediates have fewer degrees of freedom than comparable intermediates, and are thus more rigid. The concentration of assembly pathways on a few intermediates with distinguished geometric properties is biologically and physically important, and suggests deeper mathematical structure. PMID:25148546

Kaplan, Ryan; Klobušický, Joseph; Pandey, Shivendra; Gracias, David H; Menon, Govind

2014-01-01

235

Viral Quasispecies Assembly via Maximal Clique Enumeration  

PubMed Central

Virus populations can display high genetic diversity within individual hosts. The intra-host collection of viral haplotypes, called viral quasispecies, is an important determinant of virulence, pathogenesis, and treatment outcome. We present HaploClique, a computational approach to reconstruct the structure of a viral quasispecies from next-generation sequencing data as obtained from bulk sequencing of mixed virus samples. We develop a statistical model for paired-end reads accounting for mutations, insertions, and deletions. Using an iterative maximal clique enumeration approach, read pairs are assembled into haplotypes of increasing length, eventually enabling global haplotype assembly. The performance of our quasispecies assembly method is assessed on simulated data for varying population characteristics and sequencing technology parameters. Owing to its paired-end handling, HaploClique compares favorably to state-of-the-art haplotype inference methods. It can reconstruct error-free full-length haplotypes from low coverage samples and detect large insertions and deletions at low frequencies. We applied HaploClique to sequencing data derived from a clinical hepatitis C virus population of an infected patient and discovered a novel deletion of length 357±167 bp that was validated by two independent long-read sequencing experiments. HaploClique is available at https://github.com/armintoepfer/haploclique. A summary of this paper appears in the proceedings of the RECOMB 2014 conference, April 2-5. PMID:24675810

Topfer, Armin; Marschall, Tobias; Bull, Rowena A.; Luciani, Fabio

2014-01-01

236

Flexible Foot Test Assembly  

SciTech Connect

A test model of the flexible foot support was constructed early in the design stages to check its reactions to applied loads. The prototype was made of SS 304 and contained four vertical plates as opposed to the fourteen Inconel 718 plates which comprise the actual structure. Due to the fact that the prototype was built before the design of the support was finalized, the plate dimensions are different from those of the actual proposed design (i.e. model plate thickness is approximately one-half that of the actual plates). See DWG. 3740.210-MC-222376 for assembly details of the test model and DWG. 3740.210-MB-222377 for plate dimensions. This stanchion will be required to not only support the load of the inner vessel of the cryostat and its contents, but it must also allow for the movement of the vessel due to thermal contraction. Assuming that each vertical plate acts as a column, then the following formula from the Manual of Steel Construction (American Institute of Steel Construction, Inc., Eigth edition, 1980) can be applied to determine whether or not such columns undergoing simultaneous axial compression and transverse loading are considered safe for the given loading. The first term is representative of the axially compressive stress, and the second term, the bending stress. If the actual compressive stress is greater than 15% of the allowable compressive stress, then there are additional considerations which must be accounted for in the bending stress term.

Kurita, C.H.; /Fermilab

1987-04-27

237

Subsea wellhead assembly  

SciTech Connect

A subsea wellhead assembly for areas subject to iceberg scouring including an upper conductor in a well bore and a lower conductor in the well bore with the upper end of the lower conductor being within the lower end of the upper conductor and connected thereto by a weak connection and the upper end of the lower conductor being below the maximum iceberg scour depth and means for connecting said conductors, said connecting means having sufficient strength to withstand bending loads during drilling and being removable for installation of production equipment. Additionally production equipment in the well bore includes a block valve supported within the second conductor and a production string extending upward from the block valve and having a weak point within the upper end of the second conductor whereby the well control is not lost by deep iceberg scouring since the production control equipment is within the second conductor which is not damaged by the scouring and the production equipment extending thereabove fails without damage to the lower control equipment or loss of the well.

Kelly, T. P.

1984-12-11

238

Concentric tube support assembly  

DOEpatents

An assembly (45) includes a plurality of separate pie-shaped segments (72) forming a disk (70) around a central region (48) for retaining a plurality of tubes (46) in a concentrically spaced apart configuration. Each segment includes a support member (94) radially extending along an upstream face (96) of the segment and a plurality of annularly curved support arms (98) transversely attached to the support member and radially spaced apart from one another away from the central region for receiving respective upstream end portions of the tubes in arc-shaped spaces (100) between the arms. Each segment also includes a radial passageway (102) formed in the support member for receiving a fluid segment portion (106) and a plurality of annular passageways (104) formed in the support arms for receiving respective arm portions (108) of the fluid segment portion from the radial passageway and for conducting the respective arm portions into corresponding annular spaces (47) formed between the tubes retained by the disk.

Rubio, Mark F.; Glessner, John C.

2012-09-04

239

IFAS FACULTY ASSEMBLY MINUTESMINUTESMINUTESMINUTES  

E-print Network

Kaufman · Bob Hochmuth · Nicole Stedman · Bill Lindberg · Mercy Olmstead Priorities for the 2013 Report in October ­ State of the Institution COMMITTEE REPORTS IRC ­ DR. KEITH SCHNEIDER · Professor

Jawitz, James W.

240

Drive piston assembly for a valve actuator assembly  

DOEpatents

A drive piston assembly is provided that is operable to selectively open a poppet valve. The drive piston assembly includes a cartridge defining a generally stepped bore. A drive piston is movable within the generally stepped bore and a boost sleeve is coaxially disposed with respect to the drive piston. A main fluid chamber is at least partially defined by the generally stepped bore, drive piston, and boost sleeve. First and second feedback chambers are at least partially defined by the drive piston and each are disposed at opposite ends of the drive piston. At least one of the drive piston and the boost sleeve is sufficiently configured to move within the generally stepped bore in response to fluid pressure within the main fluid chamber to selectively open the poppet valve. A valve actuator assembly and engine are also provided incorporating the disclosed drive piston assembly.

Sun, Zongxuan (Troy, MI)

2010-02-23

241

Curved conveyor section guide assembly  

SciTech Connect

A guide assembly for a curved conveyor section of a scraperchain conveyor guides the scraper assembly from a first straight conveyor portion round the curved conveyor section to a second straight conveyor portion. This guiding is accomplished by a pair of independently rotatable pulley wheels. A further pair of independently rotatable pulley wheels are provided to guide the drive chain of a plough round the curved conveyor section. This enables the plough to be driven to and fro along the first straight conveyor portion by a drive station attached to the second straight conveyor portion adjacent to the guide assembly.

Truszczinski, H.

1981-02-03

242

PEPC LRU: Ball Support Assembly  

SciTech Connect

The PEPC LRU upper ball support assembly consists of a ball and a pneumatic air cylinder/conical seat latching mechanism to be attached to the optics support frame,and a ball attached to the PEPC LRU. Both components are designed to allow manual positioning in three axes. Upon insertion of the PEPC LRU into the structure, the upper pneumatic cylinder is actuated to latch the two assemblies together through the conical seat device to grab the lower ball to support the LRU weight. To be conservative, the design load for the assembly is 1500 pounds (the prototype PEPC LRU weight was measured to be near 1380 pounds).

Alger, T

1999-05-14

243

Cooling assembly for fuel cells  

DOEpatents

A cooling assembly for fuel cells having a simplified construction whereby coolant is efficiently circulated through a conduit arranged in serpentine fashion in a channel within a member of such assembly. The channel is adapted to cradle a flexible, chemically inert, conformable conduit capable of manipulation into a variety of cooling patterns without crimping or otherwise restricting of coolant flow. The conduit, when assembled with the member, conforms into intimate contact with the member for good thermal conductivity. The conduit is non-corrodible and can be constructed as a single, manifold-free, continuous coolant passage means having only one inlet and one outlet.

Kaufman, Arthur (West Orange, NJ); Werth, John (Princeton, NJ)

1990-01-01

244

Additive assembly of digital materials  

E-print Network

This thesis develops the use of additive assembly of press-fit digital materials as a new rapid-prototyping process. Digital materials consist of a finite set of parts that have discrete connections and occupy discrete ...

Ward, Jonathan (Jonathan Daniel)

2010-01-01

245

IFAS FACULTY ASSEMBLY EXECUTIVE COMMITTEE  

E-print Network

IFAS FACULTY ASSEMBLY EXECUTIVE COMMITTEE MARCH 5, 2013 1:00 PM ­ 3:00 PM 122 FRASIER ROGERS HALL a presentation to that effect 2. IRC (Infrastructure and Resources Committee) ­ Steve Futch a. IFAS business hubs

Jawitz, James W.

246

IFAS FACULTY ASSEMBLY EXECUTIVE COMMITTEE  

E-print Network

IFAS FACULTY ASSEMBLY EXECUTIVE COMMITTEE AUGUST 9, 2012 1:15 ­ 3:15 PM 122 FRASIER ROGERS HALL yet. - Steve Futch is potential leader ­ IRC committee needs to nominate chair. 2. PWC Committee (Gene

Jawitz, James W.

247

IFAS FACULTY ASSEMBLY EXECUTIVE COMMITTEE  

E-print Network

IFAS FACULTY ASSEMBLY EXECUTIVE COMMITTEE NOVEMBER 13, 2012 1:30 ­ 3:00 PM 122 FRASIER ROGERS HALL COMMITTEE REPORTS 1. PWC Committee - Gene McAvoy 2. IRC (Infrastructure and Resources Committee) ­ Steve

Jawitz, James W.

248

Automated Solar Panel Assembly Line.  

National Technical Information Service (NTIS)

The initial stage of the automated solar panel assembly line program was devoted to concept development and proof of approach through simple experimental verification. In this phase, laboratory bench models were built to demonstrate and verify concepts. F...

H. Somberg

1981-01-01

249

Gravity Probe B Assembled  

NASA Technical Reports Server (NTRS)

In this photo, the Gravity Probe B (GP-B) space vehicle is being assembled at the Sunnyvale, California location of the Lockheed Martin Corporation. The GP-B is the relativity experiment developed at Stanford University to test two extraordinary predictions of Albert Einstein's general theory of relativity. The experiment will measure, very precisely, the expected tiny changes in the direction of the spin axes of four gyroscopes contained in an Earth-orbiting satellite at a 400-mile altitude. So free are the gyroscopes from disturbance that they will provide an almost perfect space-time reference system. They will measure how space and time are very slightly warped by the presence of the Earth, and, more profoundly, how the Earth's rotation very slightly drags space-time around with it. These effects, though small for the Earth, have far-reaching implications for the nature of matter and the structure of the Universe. GP-B is among the most thoroughly researched programs ever undertaken by NASA. This is the story of a scientific quest in which physicists and engineers have collaborated closely over many years. Inspired by their quest, they have invented a whole range of technologies that are already enlivening other branches of science and engineering. Launched April 20, 2004 , the GP-B program was managed for NASA by the Marshall Space Flight Center. Development of the GP-B is the responsibility of Stanford University along with major subcontractor Lockheed Martin Corporation. (Image credit to Russ Underwood, Lockheed Martin Corporation).

2000-01-01

250

Hear Exchange Assembly  

DOEpatents

A heat exchange assembly comprises a plurality of plates disposed in a spaced-apart arrangement, each of the plurality of plates includes a plurality of passages extending internally from a first end to a second end for directing flow of a heat transfer fluid in a first plane, a plurality of first end-piece members equaling the number of plates and a plurality of second end-piece members also equaling the number of plates, each of the first and second end-piece members including a recessed region adapted to fluidly connect and couple with the first and second ends of the plate, respectively, and further adapted to be affixed to respective adjacent first and second end-piece members in a stacked formation, and each of the first and second end-piece members further including at least one cavity for enabling entry of the heat transfer fluid into the plate, exit of the heat transfer fluid from the plate, or 180.degree. turning of the fluid within the plate to create a serpentine-like fluid flow path between points of entry and exit of the fluid, and at least two fluid conduits extending through the stacked plurality of first and second end-piece members for providing first fluid connections between the parallel fluid entry points of adjacent plates and a fluid supply inlet, and second fluid connections between the parallel fluid exit points of adjacent plates and a fluid discharge outlet so that the heat transfer fluid travels in parallel paths through each respective plate.

Lowenstein, Andrew (Princeton, NJ); Sibilia, Marc (Princeton, NJ); Miller, Jeffrey (Rocky Hill, NJ); Tonon, Thomas S. (Princeton, NJ)

2003-05-27

251

Wafer scale micromachine assembly method  

DOEpatents

A method for fusing together, using diffusion bonding, micromachine subassemblies which are separately fabricated is described. A first and second micromachine subassembly are fabricated on a first and second substrate, respectively. The substrates are positioned so that the upper surfaces of the two micromachine subassemblies face each other and are aligned so that the desired assembly results from their fusion. The upper surfaces are then brought into contact, and the assembly is subjected to conditions suited to the desired diffusion bonding.

Christenson, Todd R. (Albuquerque, NM)

2001-01-01

252

Developmental self-assembly of a DNA tetrahedron.  

PubMed

Kinetically controlled isothermal growth is fundamental to biological development, yet it remains challenging to rationally design molecular systems that self-assemble isothermally into complex geometries via prescribed assembly and disassembly pathways. By exploiting the programmable chemistry of base pairing, sophisticated spatial and temporal control have been demonstrated in DNA self-assembly, but largely as separate pursuits. By integrating temporal with spatial control, here we demonstrate the "developmental" self-assembly of a DNA tetrahedron, where a prescriptive molecular program orchestrates the kinetic pathways by which DNA molecules isothermally self-assemble into a well-defined three-dimensional wireframe geometry. In this reaction, nine DNA reactants initially coexist metastably, but upon catalysis by a DNA initiator molecule, navigate 24 individually characterizable intermediate states via prescribed assembly pathways, organized both in series and in parallel, to arrive at the tetrahedral final product. In contrast to previous work on dynamic DNA nanotechnology, this developmental program coordinates growth of ringed substructures into a three-dimensional wireframe superstructure, taking a step toward the goal of kinetically controlled isothermal growth of complex three-dimensional geometries. PMID:24720462

Sadowski, John P; Calvert, Colby R; Zhang, David Yu; Pierce, Niles A; Yin, Peng

2014-04-22

253

Patchy particles by self assembly  

NASA Astrophysics Data System (ADS)

Patchy particles offer novel means for colloidal assembly or clustering of functional groups but are generally made by batch processes rather than self-assembly. Selective binding of multivalent ligands within a mixture of polyvalent amphiphiles provides, in principle, a mechanism for driving domain formation in self-assemblies. Divalent cations are shown here to crossbridge polyanionic amphiphiles, which thereby demix from neutral amphiphiles and form spots or rafts within vesicles as well as stripes within cylindrical micelles. Calcium- and copper-crossbridged domains of synthetic block copolymers or natural lipid (phosphatidylinositol-4,5-bisphosphate) possess tunable sizes, shapes and/or spacings that can last for years. Lateral segregation in these `responsive Janus assemblies' couples weakly to curvature and proves to be restricted within phase diagrams to narrow regimes of pH and cation concentration that are centred near the characteristic binding constants for polyacid interactions. Remixing at high pH is surprising, but a theory for strong lateral segregation shows that counterion entropy dominates electrostatic crossbridges, thus illustrating the insights gained into ligand-induced pattern formation within self-assemblies. REFERENCES - [1] D.A. Christian, A. Tian, W.G. Ellenbroek, I. Levental, P.A. Janmey, A.J. Liu, T. Baumgart, D.E. Discher. Spotted vesicles, striped micelles, and Janus assemblies induced by ligand binding. Nature Materials 8: 843--849 (2009).

Discher, Dennis; Christian, David

2010-03-01

254

Occupational Education in the Large Five Cities. Statement before the New York State Assembly Education Committee (Albany, New York, March 2, 1988). Capsule Report 88-11-CR-A.  

ERIC Educational Resources Information Center

This document reports the policy statement of the President of the University of the State of New York regarding vocational education in the five largest cities in the state. The statement provides background on how changes in the economy and the organization of work will affect the skills needed by the work force of the future. It also indicates…

Sobol, Thomas

255

Synthesis and Self-Assembly of Amphiphilic Dendrimers Based on Aliphatic Polyether-Type Dendritic Cores  

E-print Network

Synthesis and Self-Assembly of Amphiphilic Dendrimers Based on Aliphatic Polyether-Type Dendritic Manuscript Received February 22, 2004 ABSTRACT: We have prepared a series of amphiphilic dendrimers-angle X-ray scattering (WAXS) experiments. Amphiphilic dendrimer self-assembly in the solid state

Gruner, Sol M.

256

8. INTERIOR VIEW OF ASSEMBLY ROOM (REAR FACADE), UNTANKING TOWER, ...  

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

8. INTERIOR VIEW OF ASSEMBLY ROOM (REAR FACADE), UNTANKING TOWER, SHOWING PREVIOUS MODIFICATIONS (INSTALLATION OF METAL ROLL-UP DOOR, LEFT FOREGROUND). 125-TON LIFTING CRANE (TOP FOREGROUND), AND ORIGINAL FLOOR-TO-CEILING MULTI-PANE, METAL-CASED WINDOWS - Bonneville Power Administration Chehalis Substation, Untanking Tower, State Route 603, West of Interstate 5, Napavine, Lewis County, WA

257

Supramolecular hydrogen-bonding assembly of silanediols with bifunctional heterocycles.  

PubMed

X-ray crystallography showcases the distinct self-association and hydrogen-bonding patterns of organic silanediols, R2Si(OH)2, with bifunctional heterocycles for supramolecular assembly. Diffusion-ordered spectroscopy (DOSY) studies identify the dominant hydrogen-bonding patterns and structures in solution, which correlate with solid-state patterns at high concentrations. PMID:24577634

Tran, Ngon T; Wilson, Sean O; Franz, Annaliese K

2014-04-11

258

Pneumatic Power Drive Wheel and related assembly for Turntable, with ...  

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

Pneumatic Power Drive Wheel and related assembly for Turntable, with scale. Not in use August 1994. Turntable rotated with engine and tender on balance by two persons, one on either side at ground level - East Broad Top Railroad & Coal Company, Roundhouse, State Route 994, West of U.S. Route 522, Rockhill Furnace, Huntingdon County, PA

259

Templated self-assembly for complex pattern fabrication  

E-print Network

The long-term goal of my Ph.D. study has been controlling the self-assembly of various materials using state-of-the-art nanofabrication techniques. Electron-beam lithography has been used for decades to generate nanoscale ...

Chang, Jae-Byum

2014-01-01

260

Electric field mediated colloidal assembly and control  

NASA Astrophysics Data System (ADS)

This dissertation presents video microscopy measurements and computer simulations of colloidal particle interactions in inhomogeneous, high-frequency AC electric fields. The interactions of particles with each other and inhomogeneous electric fields are quantified as a function of concentration, field amplitude, and frequency. Visual state diagrams show that these interactions in concentrated systems produce quasi-two dimensional microstructures including confined hard disk fluids, oriented dipolar chains, and oriented hexagonal close packed crystals. The interaction of a particle interacting with an electric field is directly measured with analyses of a single diffusing colloid within electric fields in the absence of many body effects. Concentrated systems are characterized in terms of density profiles across the electrode gap and angular pair distribution functions. An inverse Monte Carlo analysis extracted the induced dipole-induced dipole interaction from concentrated measurements. A single adjustable parameter consistently modified the induced dipole-field potential and the induced dipole-induced dipole potential to account for modification of the local electric field as the result of the local particle concentration, frequency and configuration. Confocal laser scanning microscopy (CLSM) perform sensitive measurements of internal three dimensional structure of crystals assembled in an interfacial quadrupole electrode device. Radial distributions as functions of elevation are used to characterize the equilibrium structure. A single adjustable parameter modified known potentials to match Monte Carlo simulations with experiment. The local density from experiment and simulation matched the expected density calculated from a balance of osmotic pressure and dielectrophoretic compression. Simulations qualitatively matched experimental observations of microstructure as a function of field amplitude. Programmable assembly for colloidal crystals is implemented in the quadrupole electrode device by guiding the dynamic evolution of a colloidal ensemble. A feedback method is used to control electric field mediated assembly based on real-time sensing and actuation single and multiple electrokinetic mechanisms. Sensing is achieved using particle tracking and order parameter computation to quantify the degree of order during the assembly process. A geometrical parameter for hexagonal close packing and radius of gyration are investigated as order parameters for quantifying condensation and crystallization. Colloidal crystal assembly and disassembly is actuated using electroosmosis and negative and positive dielectrophoresis (i.e. dipole-field interactions).

Juarez, Jaime Javier

261

Reproducible EnzymeReproducible Enzyme Assembly and CatalyticAssembly and Catalytic  

E-print Network

Reproducible EnzymeReproducible Enzyme Assembly and CatalyticAssembly and Catalytic Activity Accomplishments #12;Reproducible Enzyme Assembly and CatalyticReproducible Enzyme Assembly and Catalytic Activity in Reusable BioMEMSActivity in Reusable BioMEMS Accomplishment Pro-tagged Pfs enzymes are spatially assembled

Rubloff, Gary W.

262

Meta assembler enhancements and generalized linkage editor  

NASA Technical Reports Server (NTRS)

A meta Assembler for NASA was developed. The initial development of the Meta Assembler for the SUMC was performed. The capabilities included assembly for both main and micro level programs. A period of checkout and utilization to verify the performance of the Meta Assembler was undertaken. Additional enhancements were made to the Meta Assembler which expanded the target computer family to include architectures represented by the PDP-11, MODCOMP 2, and Raytheon 706 computers.

1979-01-01

263

Assembling pieces of the centromere epigenetics puzzle  

PubMed Central

The centromere is a key region for cell division where the kinetochore assembles, recognizes and attaches to microtubules so that each sister chromatid can segregate to each daughter cell. The centromeric chromatin is a unique rigid chromatin state promoted by the presence of the histone H3 variant CENP-A, in which epigenetic histone modifications of both heterochromatin or euchromatin states and associated protein elements are present. Although DNA sequence is not regarded as important for the establishment of centromere chromatin, it has become clear that this structure is formed as a result of a highly regulated epigenetic event that leads to the recruitment and stability of kinetochore proteins. We describe an integrative model for epigenetic processes that conform regional chromatin interactions indispensable for the recruitment and stability of kinetochore proteins. If alterations of these chromatin regions occur, chromosomal instability is promoted, although segregation may still take place. PMID:22207360

Gonzalez-Barrios, Rodrigo; Soto-Reyes, Ernesto; Herrera, Luis A.

2012-01-01

264

Buckling instability of self-assembled colloidal columns.  

PubMed

Suspended, slender self-assembled domains of magnetically responsive colloids are observed to buckle in microgravity. Upon cessation of the magnetic field that drives their assembly, these columns expand axially and buckle laterally. This phenomenon resembles the buckling of long beams due to thermal expansion; however, linear stability analysis predicts that the colloidal columns are inherently susceptible to buckling because they are freely suspended in a Newtonian fluid. The dominant buckling wavelength increases linearly with column thickness and is quantitatively described using an elastohydrodynamic model and the suspension thermodynamic equation of state. PMID:25302919

Swan, James W; Vasquez, Paula A; Furst, Eric M

2014-09-26

265

Buckling Instability of Self-Assembled Colloidal Columns  

NASA Astrophysics Data System (ADS)

Suspended, slender self-assembled domains of magnetically responsive colloids are observed to buckle in microgravity. Upon cessation of the magnetic field that drives their assembly, these columns expand axially and buckle laterally. This phenomenon resembles the buckling of long beams due to thermal expansion; however, linear stability analysis predicts that the colloidal columns are inherently susceptible to buckling because they are freely suspended in a Newtonian fluid. The dominant buckling wavelength increases linearly with column thickness and is quantitatively described using an elastohydrodynamic model and the suspension thermodynamic equation of state.

Swan, James W.; Vasquez, Paula A.; Furst, Eric M.

2014-09-01

266

Hydrodynamic assembly for Fast Ignition  

NASA Astrophysics Data System (ADS)

We present directly and indirectly driven implosion designs for Fast Ignition. Directly driven designs using various laser illumination wavelengths are described. We compare these designs with simple hydrodynamic efficiency models. Capsules illuminated with less than 1 MJ of light with perfect zooming at low intensity and low contrast ratio in power can assemble 4 mg of fuel to column density in excess of 3 g/cm^2. We contrast these designs with more optimized designs that lead to Guderley-style self similar implosions. Indirectly driven capsules absorbing 75 kJ of xrays can assemble 0.7 mg to column density 2.7 g/cm^2 in 1D simulations. We describe 2-D simulations including both capsules and attached cones driven by radiation. We describe issues in assembling fuel near the cone tip and cone disruption.

Tabak, Max; Clark, Daniel; Town, Richard; Hatchett, Stephen

2007-11-01

267

The elegans of spindle assembly  

PubMed Central

The Caenorhabditis elegans one-cell embryo is a powerful system in which to study microtubule organization because this large cell assembles both meiotic and mitotic spindles within the same cytoplasm over the course of 1 h in a stereotypical manner. The fertilized oocyte assembles two consecutive acentrosomal meiotic spindles that function to reduce the replicated maternal diploid set of chromosomes to a single-copy haploid set. The resulting maternal DNA then unites with the paternal DNA to form a zygotic diploid complement, around which a centrosome-based mitotic spindle forms. The early C. elegans embryo is amenable to live-cell imaging and electron tomography, permitting a detailed structural comparison of the meiotic and mitotic modes of spindle assembly. PMID:20339898

Greenan, Garrett; O'Toole, Eileen

2010-01-01

268

FUEL ASSEMBLY SHAKER TEST SIMULATION  

SciTech Connect

This report describes the modeling of a PWR fuel assembly under dynamic shock loading in support of the Sandia National Laboratories (SNL) shaker test campaign. The focus of the test campaign is on evaluating the response of used fuel to shock and vibration loads that a can occur during highway transport. Modeling began in 2012 using an LS-DYNA fuel assembly model that was first created for modeling impact scenarios. SNL’s proposed test scenario was simulated through analysis and the calculated results helped guide the instrumentation and other aspects of the testing. During FY 2013, the fuel assembly model was refined to better represent the test surrogate. Analysis of the proposed loads suggested the frequency band needed to be lowered to attempt to excite the lower natural frequencies of the fuel assembly. Despite SNL’s expansion of lower frequency components in their five shock realizations, pretest predictions suggested a very mild dynamic response to the test loading. After testing was completed, one specific shock case was modeled, using recorded accelerometer data to excite the model. Direct comparison of predicted strain in the cladding was made to the recorded strain gauge data. The magnitude of both sets of strain (calculated and recorded) are very low, compared to the expected yield strength of the Zircaloy-4 material. The model was accurate enough to predict that no yielding of the cladding was expected, but its precision at predicting micro strains is questionable. The SNL test data offers some opportunity for validation of the finite element model, but the specific loading conditions of the testing only excite the fuel assembly to respond in a limited manner. For example, the test accelerations were not strong enough to substantially drive the fuel assembly out of contact with the basket. Under this test scenario, the fuel assembly model does a reasonable job of approximating actual fuel assembly response, a claim that can be verified through direct comparison of model results to recorded test results. This does not offer validation for the fuel assembly model in all conceivable cases, such as high kinetic energy shock cases where the fuel assembly might lift off the basket floor to strike to basket ceiling. This type of nonlinear behavior was not witnessed in testing, so the model does not have test data to be validated against.a basis for validation in cases that substantially alter the fuel assembly response range. This leads to a gap in knowledge that is identified through this modeling study. The SNL shaker testing loaded a surrogate fuel assembly with a certain set of artificially-generated time histories. One thing all the shock cases had in common was an elimination of low frequency components, which reduces the rigid body dynamic response of the system. It is not known if the SNL test cases effectively bound all highway transportation scenarios, or if significantly greater rigid body motion than was tested is credible. This knowledge gap could be filled through modeling the vehicle dynamics of a used fuel conveyance, or by collecting acceleration time history data from an actual conveyance under highway conditions.

Klymyshyn, Nicholas A.; Sanborn, Scott E.; Adkins, Harold E.; Hanson, Brady D.

2013-05-30

269

49 CFR 393.93 - Seats, seat belt assemblies, and seat belt assembly anchorages.  

Code of Federal Regulations, 2010 CFR

...belt assemblies, and seat belt assembly anchorages. 393.93 Section 393.93 Transportation Other Regulations Relating to...SAFE OPERATION Miscellaneous Parts and Accessories § 393.93 Seats, seat belt assemblies, and seat belt...

2010-10-01

270

The Archimedes 2 mechanical assembly planning system  

SciTech Connect

We describe the implementation and performance of Archimedes 2, an integrated mechanical assembly planning system. Archimedes 2 includes two planners, two assembly sequence animation facilities, and an associated robotic workcell. Both planners use full 3 dimensional data. A rudimentary translator from high level assembly plans to control code for the robotic workcell has also been implemented. We can translate data from a commercial CAD system into input data for the system, which has allowed us to plan assembly sequences for many industrial assemblies. Archimedes 2 has been used to plan sequences for assemblies consisting of 5 to 109 parts. We have also successfully taken a CAD model of an assembly, produced an optimized assembly sequence for it, and translated the plan into robot code, which successfully assembles the device specified in the model.

Kaufman, S.G.; Wilson, R.H.; Jones, R.E.; Calton, T.L.; Ames, A.L.

1996-03-01

271

Geometric and elastic properties and mechanical phase separation phenomena in self-assembling mesoscopic helical springs  

E-print Network

Helical ribbons with pitch angles of either 11? or 54? self-assemble in a wide variety of quaternary surfactant-phospholipid/fatty acid-sterol-water systems. In all of the systems studied, the thermodynamically stable state ...

Smith, Brice Christopher, 1976-

2003-01-01

272

Magnetically suspended reaction wheel assembly  

NASA Technical Reports Server (NTRS)

The magnetically suspended reaction wheel assembly (MSRWA) is the product of a development effort funded by the Air Force Materials Laboratory (AFML) at Wright Patterson AFB. The specific objective of the project was to establish the manufacturing processes for samarium cobalt magnets and demonstrate their use in a space application. The development was successful on both counts. The application portion of the program, which involves the magnetically suspended reaction wheel assembly, is emphasized. The requirements for the reaction wheel were based on the bias wheel requirements of the DSP satellite. The tasks included the design, fabrication, and test of the unit to the DSP program qualification requirements.

Stocking, G.

1984-01-01

273

DNA-guided nanoparticle assemblies  

DOEpatents

In some embodiments, DNA-capped nanoparticles are used to define a degree of crystalline order in assemblies thereof. In some embodiments, thermodynamically reversible and stable body-centered cubic (bcc) structures, with particles occupying <.about.10% of the unit cell, are formed. Designs and pathways amenable to the crystallization of particle assemblies are identified. In some embodiments, a plasmonic crystal is provided. In some aspects, a method for controlling the properties of particle assemblages is provided. In some embodiments a catalyst is formed from nanoparticles linked by nucleic acid sequences and forming an open crystal structure with catalytically active agents attached to the crystal on its surface or in interstices.

Gang, Oleg; Nykypanchuk, Dmytro; Maye, Mathew; van der Lelie, Daniel

2013-07-16

274

TIGRA: a targeted iterative graph routing assembler for breakpoint assembly.  

PubMed

Recent progress in next-generation sequencing has greatly facilitated our study of genomic structural variation. Unlike single nucleotide variants and small indels, many structural variants have not been completely characterized at nucleotide resolution. Deriving the complete sequences underlying such breakpoints is crucial for not only accurate discovery, but also for the functional characterization of altered alleles. However, our current ability to determine such breakpoint sequences is limited because of challenges in aligning and assembling short reads. To address this issue, we developed a targeted iterative graph routing assembler, TIGRA, which implements a set of novel data analysis routines to achieve effective breakpoint assembly from next-generation sequencing data. In our assessment using data from the 1000 Genomes Project, TIGRA was able to accurately assemble the majority of deletion and mobile element insertion breakpoints, with a substantively better success rate and accuracy than other algorithms. TIGRA has been applied in the 1000 Genomes Project and other projects and is freely available for academic use. PMID:24307552

Chen, Ken; Chen, Lei; Fan, Xian; Wallis, John; Ding, Li; Weinstock, George

2014-02-01

275

D0 Silicon Upgrade: Ladder Assembly Sequences  

SciTech Connect

This is an abridged version of the assembly sequence described by the DO assembly subgroup of Cooper, Hrycyk, Kowalski, Rapidis, and Ratzmann. This primarily is used to indicate major steps during the sequence and to list fixturing requirements. Assembly - (1) Place support rails in (1) 3 Chip Ladder Construction fixture. The two rails get held under vacuum. (2) Apply adhesive to the region where contact will be made with the beryllium substrates. (3) Place underside beryllium pieces (active and dummy ends) into the (1) 3 Chip Ladder Construction fixture. These pieces get placed in the fixture against the appropriate pins to mimic final positioning in the bulkhead. Apply vacuum to the beryllium pieces. Allow to cure? (4) Align silicon in (1) 3 Chip Ladder Construction fixture. Reference features on the fixture will be parameterized. Holes in the fixture near the silicon center line will be targeted to set the silicon axis relative to the beryllium slot edge. Z positioning of the detectors will be achieved by shimming between the detectors and butting up the end of the silicon against the fixture. (5) Remove silicon detectors and apply adhesive to the rails and upper surfaces of the beryllium. (6) Replace silicon and check final position of the detectors. (7) Release vacuum on the rails so they cure in a stress-free state. Allow adhesive to cure. (8) Apply adhesive and align HDI to the silicon using (2) 3 Chip HDI Gluing fixture. The HDI will have tabs which are held by the fixture for location relative to the detectors. Allow adhesive to cure. (9) Move ladder to (3) 3 Chip Wirebonding Fixture. Transfer fixture to the wirebonder and bond chip-silicon and silicon-silicon.

Ratzmann, Paul; /Fermilab

1994-08-17

276

Enthalpy changes in microtubule assembly from pure tubulin.  

PubMed

The enthalpy changes that occur in the self-assembly of tubulin into microtubules were examined by adiabatic differential heat capacity microcalorimetry and by isothermal batch microcalorimetry. Tubulin solutions at concentrations between 7 and 17 mg/mL were heated from 0 to 40 degrees C at heating rates of 1 or 2 deg/min in pH 6.8 or 7.0 assembly buffers containing 20 mM MES, 100 mM glutamic acid, 5 mM MgCl2, 3.4 M glycerol, and either 0.5 mM GMP-PCP or 1 mM GTP. The assembly reaction in the presence of GTP was characterized by a complex heat-uptake pattern consisting of a broad endotherm with a sharper exotherm superimposed on it, similar to assembly in a GTP phosphate buffer [Hinz, H.-J., Gorbunoff, M.J., Price, B., & Timasheff, S.N. (1979) Biochemistry 18,3084]. Replacement of GTP by the nonhydrolyzable analogue resulted in a pattern typical for an endothermic reaction only. These results have permitted the assignment of the endothermic process to microtubule assembly and of the exothermic process to the resultant GTP hydrolysis. In these studies equilibration was found to be slow, several hours of cooling being required for the system to return to its original state. Turbidity scans also revealed hysteresis between consecutive scans and a displacement of the depolymerization transition midpoint to a lower temperature than that of assembly. The disassembly of microtubules was examined in batch calorimetry experiments in pH 7.0 phosphate, 1 mM GTP, 16 mM MgCl2, and 3.4 M glycerol, in which tubulin assembled into microtubules was diluted to below the critical concentration.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3814584

Hinz, H J; Timasheff, S N

1986-12-16

277

Calixarene-encapsulated nanoparticles: self-assembly into functional nanomaterials†  

PubMed Central

Calixarenes are excellent surfactants for enhancing the dispersion and self-assembly of metal nanoparticles into well-defined structures, particularly those with unit length scales in the 10–100 nm size range. Particles within these ensembles are strongly coupled, giving rise to unique collective optical or magnetic properties. The self-assembled nanostructures described in this feature article include 2D arrays of colloidal Au nanoparticles with size-dependent plasmonic responses, and sub-100 nm Co nanoparticle rings with chiral magnetic states. These nanoparticle assemblies may be further developed for applications in chemical sensing based on surface-enhanced Raman scattering (SERS) and as binary elements for nonvolatile memory, respectively. PMID:16582988

Wei, Alexander

2007-01-01

278

Comparing open and closed molecular self-assembly  

E-print Network

We study theoretically in the present work the self-assembly of molecules in an open system, which is fed by monomers and depleted in partial or complete clusters. Such a scenario is likely to occur for example in the context of viral self-assembly. We provide a general formula for the mean-field size distribution which is valid both at equilibrium in a closed system, and in the stationary state in an open system. This allows us to explore in a simple way out-of-equilibrium features for self-assembly and compare them to equilibrium properties. In particular, we identify a region of parameter space for which the out-of-equilibrium size distribution in the presence of external fluxes is equal to the equilibrium size distribution in the absence of external fluxes, up to a constant renormalization factor. The range of validity of this result and its consequences are discussed.

Martin Castelnovo; Timothée Verdier; Lionel Foret

2014-02-17

279

Final data report for the instrumented fuel assembly (IFA)-432  

SciTech Connect

This report presents the in-reactor data collected during the irradiation of the six-rod instrumented fuel assembly (IFA)-432 in the Halden Boiling Water Reactor (HBWR) from June 1980 through June 1981. This Pacific Northwest Laboratory (PNL)-designed assembly was one of a series of US Nuclear Regulatory Commission (NRC)-sponsored tests to obtain data for the development and verification of steady-state fuel performance computer codes. IFA-432 operated from December 1975 until June 1981, when it was removed from the reactor. Two of the rods were removed for examination, and the assembly was reinserted in December 1981 to obtain additional data. Fuel centerline temperatures, cladding elongations, internal fuel rod pressures, and local powers at thermocouple positions were monitored during the irradiation of IFA-432; and the resulting data are presented in this report.

Bradley, E.R.; Cunningham, M.E.; Lanning, D.D.

1982-06-01

280

Supramolecular Assembly of Amelogenin Nanospheres into Birefringent Microribbons  

NASA Astrophysics Data System (ADS)

Although both tooth enamel and bone are composed of organized assemblies of carbonated apatite crystals, enamel is unusual in that it does not contain collagen nor does it remodel. Self-assembly of amelogenin protein into nanospheres has been recognized as a key factor in controlling the oriented and elongated growth of carbonated apatite crystals during dental enamel biomineralization. We report the in vitro formation of birefringent microribbon structures that were generated through the supramolecular assembly of amelogenin nanospheres. These microribbons have diffraction patterns that indicate a periodic structure of crystalline units along the long axis. The growth of apatite crystals orientated along the c axis and parallel to the long axes of the microribbons was observed in vitro. The linear arrays (chains) of nanospheres observed as intermediate states before the microribbon formation give an important indication as to the function of amelogenin in controlling the oriented growth of apatite crystals during enamel mineralization.

Du, Chang; Falini, Giuseppe; Fermani, Simona; Abbott, Christopher; Moradian-Oldak, Janet

2005-03-01

281

Comments on the Report of the California State University on the Potential Effects of Its 1988 Course Requirements. A Report to the Legislature in Response to Assembly Concurrent Resolution 158 (Chapter 165 of the Statutes of 1986).  

ERIC Educational Resources Information Center

The potential effects of California State University's (CSU) 1988 freshman admission requirements are evaluated in a CSU's report and in commentary on the report by the California Postsecondary Education Commission. Attention is directed to eight concerns expressed by the California Legislature regarding the potential impact of the new course…

California State Postsecondary Education Commission, Sacramento.

282

Connecticut Task Force on Charter Schools Report. Prepared for the Education Committee of the Connecticut General Assembly and the Connecticut State Board of Education Pursuant to Public Act 91-285.  

ERIC Educational Resources Information Center

In this report, Connecticut's Task Force on Charter Schools recommends enacting legislation to establish six pilot charter schools to begin operation in fall 1994. As public schools or educational programs operating under a State Board of Education charter, charter schools would be: committed to quality student outcomes; staffed and controlled by…

Connecticut State Dept. of Education, Hartford.

283

Two criteria for the selection of assembly plans - Maximizing the flexibility of sequencing the assembly tasks and minimizing the assembly time through parallel execution of assembly tasks  

NASA Technical Reports Server (NTRS)

The authors introduce two criteria for the evaluation and selection of assembly plans. The first criterion is to maximize the number of different sequences in which the assembly tasks can be executed. The second criterion is to minimize the total assembly time through simultaneous execution of assembly tasks. An algorithm that performs a heuristic search for the best assembly plan over the AND/OR graph representation of assembly plans is discussed. Admissible heuristics for each of the two criteria introduced are presented. Some implementation issues that affect the computational efficiency are addressed.

Homem De Mello, Luiz S.; Sanderson, Arthur C.

1991-01-01

284

Synthesis and assembly of nanomaterials under magnetic fields.  

PubMed

Traditionally, magnetic field has long been regarded as an important means for studying the magnetic properties of materials. With the development of synthesis and assembly methods, magnetic field, similar to conventional reaction conditions such as temperature, pressure, and surfactant, has been developed as a new parameter for synthesizing and assembling special structures. To date, magnetic fields have been widely employed for materials synthesis and assembly of one-dimensional (1D), two-dimensional (2D) or three-dimensional (3D) aggregates. In this review, we aim to provide a summary on the applications of magnetic fields in this area. Overall, the objectives of this review are: (1) to theoretically discuss several factors that refer to magnetic field effects (MFEs); (2) to review the magnetic-field-induced synthesis of nanomaterials; the 1D structure of various nanomaterials, such as metal oxides/sulfide, metals, alloys, and carbon, will be described in detail. Moreover, the MFEs on spin states of ions, magnetic domain and product phase distribution will be also involved; (3) to review the alignment of carbon nanotubes, assembly of magnetic nanomaterials and photonic crystals with the help of magnetic fields; and (4) to sketch the future opportunities that magnetic fields can face in the area of materials synthesis and assembly. PMID:25338267

Hu, Lin; Zhang, Ruirui; Chen, Qianwang

2014-11-01

285

DNA-templated assembly of droplet-derived PEG microtissues  

PubMed Central

Patterning multiple cell types is a critical step for engineering functional tissues, but few methods provide three-dimensional positioning at the cellular length scale. Here, we present a “bottom-up” approach for fabricating multicellular tissue constructs that utilizes DNA-templated assembly of 3D cell-laden hydrogel microtissues. A flow focusing-generated emulsion of photopolymerizable prepolymer is used to produce 100 ?m monodisperse microtissues at rates of 100 Hz (105/hr). Multiple cell types, including suspension and adherently cultured cells, can be encapsulated into the microtissues with high viability (~97%). We then use a DNA coding scheme to self-assemble microtissues “bottom-up” from a template that is defined using “top-down” techniques. The microtissues are derivatized with single-stranded DNA using a biotin-streptavidin linkage to the polymer network, and are assembled by sequence-specific hybridization onto spotted DNA microarrays. Using orthogonal DNA codes, we achieve multiplexed patterning of multiple microtissue types with high binding efficiency and >90% patterning specificity. Finally, we demonstrate the ability to organize multicomponent constructs composed of epithelial and mesenchymal microtissues while preserving each cell type in a 3D microenvironment. The combination of high throughput microtissue generation with scalable surface-templated assembly offers the potential to dissect mechanisms of cell-cell interaction in three dimensions in healthy and diseased states as well as provides a framework for templated assembly of larger structures for implantation. PMID:21776518

Li, Cheri Y.; Wood, David K.; Hsu, Caroline M.; Bhatia, Sangeeta N.

2012-01-01

286

Self-assembling holographic biosensors and biocomputers.  

SciTech Connect

We present concepts for self-assembly of diffractive optics with potential uses in biosensors and biocomputers. The simplest such optics, diffraction gratings, can potentially be made from chemically-stabilized microtubules migrating on nanopatterned tracks of the motor protein kinesin. We discuss the fabrication challenges involved in patterning sub-micron-scale structures with proteins that must be maintained in aqueous buffers to preserve their activity. A novel strategy is presented that employs dry contact printing onto glass-supported amino-silane monolayers of heterobifunctional crosslinkers, followed by solid-state reactions of these cross-linkers, to graft patterns of reactive groups onto the surface. Successive solution-phase addition of cysteine-mutant proteins and amine-reactive polyethylene glycol allows assembly of features onto the printed patterns. We present data from initial experiments showing successful micro- and nanopatterning of lines of single-cysteine mutants of kinesin interleaved with lines of polyethylene, indicating that this strategy can be employed to arrays of features with resolutions suitable for gratings.

Light, Yooli Kim; Bachand, George David (Sandia National Laboratories, Albuquerque, NM); Schoeniger, Joseph S.; Trent, Amanda M. (Sandia National Laboratories, Albuquerque, NM)

2006-05-01

287

Danforth Campus Emergency Assembly Points  

E-print Network

21 Danforth Campus Emergency Assembly Points 0 0.1 0.2 Miles EAP 51 50 0 0.1 0.2 Miles West Campus 64 EAP #: Location Description: Buildings to use this EAP: 1 Grassy area north of Beaumont Dorm Beaumont Dorm 2 Grassy area between Shepley Dorm & the basketball court Danforth Dorm(178), Shepley Dorm(177

Larson-Prior, Linda

288

Assembly of quasicrystalline photonic heterostructures  

DOEpatents

A method and system for assembling a quasicrystalline heterostructure. A plurality of particles is provided with desirable predetermined character. The particles are suspended in a medium, and holographic optical traps are used to position the particles in a way to achieve an arrangement which provides a desired property.

Grier, David G.; Roichman, Yael; Man, Weining; Chaikin, Paul Michael; Steinhardt, Paul Joseph

2013-03-12

289

Detection of galaxy assembly bias  

NASA Astrophysics Data System (ADS)

Assembly bias describes the finding that the clustering of dark matter haloes depends on halo formation time at fixed halo mass. In this paper, we analyse the influence of assembly bias on galaxy clustering using both semi-analytic galaxy formation models (SAMs) and observational data. At fixed stellar mass, SAMs predict that the clustering of central galaxies depends on the specific star formation rate (sSFR), with more passive galaxies having a higher clustering amplitude. We find similar trends using the Sloan Digital Sky Survey (SDSS) group catalogues, and verify that these are not affected by possible biases due to the group finding algorithm. Low-mass central galaxies reside in narrow bins of halo mass, so the observed trends of higher clustering amplitude for galaxies with lower sSFR is not driven by variations of the parent halo mass. We argue that the clustering dependence on sSFR represent a direct detection of assembly bias. In addition, contrary to what expected based on clustering of dark matter haloes, we find that low-mass central galaxies in SAMs with larger host halo mass have a lower clustering amplitude than their counter-parts residing in lower mass haloes. This results from the fact that, at fixed stellar mass, assembly bias has a stronger influence on clustering than the dependence on the parent halo mass.

Wang, Lan; Weinmann, Simone M.; De Lucia, Gabriella; Yang, Xiaohu

2013-07-01

290

In vitro assembly of catalase.  

PubMed

Most aerobic organisms contain catalase, which functions to decompose hydrogen peroxide. Typical catalases are structurally complex homo-tetrameric enzymes with one heme prosthetic group buried in each subunit. It is not known how catalase in the cell is assembled from its constituents. The bacterium Enterococcus faecalis cannot synthesize heme but can acquire it from the environment to form a cytoplasmic catalase. We have in E. faecalis monitored production of the enzyme polypeptide (KatA) depending on the availability of heme and used our findings to devise a procedure for the purification of preparative amounts of in vivo-synthesized apocatalase. We show that fully active catalase can be obtained in vitro by incubating isolated apoprotein with hemin. We have characterized features of the assembly process and describe a temperature-trapped hemylated intermediate of the enzyme maturation process. Hemylation of apocatalase does not require auxiliary cell components, but rapid assembly of active enzyme seemingly is assisted in the cell. Our findings provide insight about catalase assembly and offer new experimental possibilities for detailed studies of this process. PMID:25148685

Baureder, Michael; Barane, Elisabeth; Hederstedt, Lars

2014-10-10

291

Ultrasonic Assembly of Thermoplastic Parts  

Microsoft Academic Search

Four ultrasonic methods were evaluated for assembly of experimental plastic parts for detonators: (1) welding, (2) crimping and staking, (3) insertion, and (4) reactivation of adhesives. For welding, staking and insertion, plastics with low elastic moduli, such as acrylics and polycarbonate, produced the best results. Thermosetting, hot-melt, and solution adhesives could all be activated ultrasonically to form good bonds on

Schurman

1970-01-01

292

Closure fixture and assembly cap  

Microsoft Academic Search

A closure fixture has a slide member or valve for radioactive and toxic media, a fixture housing, a housing cover connected to the housing via a first sealing surface and a closure device with a drive mechanism arranged on the housing cover. The housing fixture comprises an additional sealing surface and an assembly cap has an interior configured to receive

L. Grein; U. Reimpell; R. Reiter

1981-01-01

293

A Bill of Rights Assembly.  

ERIC Educational Resources Information Center

Presents a student- and community-produced assembly program in which several Supreme Court cases are reenacted. Focuses on student rights concerning search and seizure, freedom of speech, and freedom of of the press. Provides a 40- to 50-minute script with roles for narrators, administrators, police officers, reporters, lawyers, and students. (CH)

Kenny, Maureen; Reilley, Margaret

1991-01-01

294

Simulated nuclear reactor fuel assembly  

DOEpatents

An apparatus for electrically simulating a nuclear reactor fuel assembly. It includes a heater assembly having a top end and a bottom end and a plurality of concentric heater tubes having electrical circuitry connected to a power source, and radially spaced from each other. An outer target tube and an inner target tube is concentric with the heater tubes and with each other, and the outer target tube surrounds and is radially spaced from the heater tubes. The inner target tube is surrounded by and radially spaced from the heater tubes and outer target tube. The top of the assembly is generally open to allow for the electrical power connection to the heater tubes, and the bottom of the assembly includes means for completing the electrical circuitry in the heater tubes to provide electrical resistance heating to simulate the power profile in a nuclear reactor. The embedded conductor elements in each heater tube is split into two halves for a substantial portion of its length and provided with electrical isolation such that each half of the conductor is joined at one end and is not joined at the other end.

Berta, Victor T. (Idaho Falls, ID)

1993-01-01

295

Simulated nuclear reactor fuel assembly  

DOEpatents

An apparatus for electrically simulating a nuclear reactor fuel assembly. It includes a heater assembly having a top end and a bottom end and a plurality of concentric heater tubes having electrical circuitry connected to a power source, and radially spaced from each other. An outer target tube and an inner target tube is concentric with the heater tubes and with each other, and the outer target tube surrounds and is radially spaced from the heater tubes. The inner target tube is surrounded by and radially spaced from the heater tubes and outer target tube. The top of the assembly is generally open to allow for the electrical power connection to the heater tubes, and the bottom of the assembly includes means for completing the electrical circuitry in the heater tubes to provide electrical resistance heating to simulate the power profile in a nuclear reactor. The embedded conductor elements in each heater tube is split into two halves for a substantial portion of its length and provided with electrical isolation such that each half of the conductor is joined at one end and is not joined at the other end.

Berta, V.T.

1993-04-06

296

In Vitro Assembly of Catalase*  

PubMed Central

Most aerobic organisms contain catalase, which functions to decompose hydrogen peroxide. Typical catalases are structurally complex homo-tetrameric enzymes with one heme prosthetic group buried in each subunit. It is not known how catalase in the cell is assembled from its constituents. The bacterium Enterococcus faecalis cannot synthesize heme but can acquire it from the environment to form a cytoplasmic catalase. We have in E. faecalis monitored production of the enzyme polypeptide (KatA) depending on the availability of heme and used our findings to devise a procedure for the purification of preparative amounts of in vivo-synthesized apocatalase. We show that fully active catalase can be obtained in vitro by incubating isolated apoprotein with hemin. We have characterized features of the assembly process and describe a temperature-trapped hemylated intermediate of the enzyme maturation process. Hemylation of apocatalase does not require auxiliary cell components, but rapid assembly of active enzyme seemingly is assisted in the cell. Our findings provide insight about catalase assembly and offer new experimental possibilities for detailed studies of this process. PMID:25148685

Baureder, Michael; Barane, Elisabeth; Hederstedt, Lars

2014-01-01

297

Fellows Celebrated at Joint Assembly  

NASA Astrophysics Data System (ADS)

The 2007 AGU Fellows were presented at the recent Joint Assembly in Acapulco, Mexico. A formal ceremony was held on 25 May 2007, where President Tim Killeen introduced each Fellow and read a brief statement of the achievements for which each had been selected. The presentations were followed by an honors fiesta at which family members and close colleagues further feted the honorees.

2007-06-01

298

Muscle assembly: a titanic achievement?  

Microsoft Academic Search

The formation of perfectly aligned myofibrils in striated muscle represents a dramatic example of supramolecular assembly in eukaryotic cells. Recently, considerable progress has been made in deciphering the roles that titin, the third most abundant protein in muscle, has in this process. An increasing number of sarcomeric proteins (ligands) are being identified that bind to specific titin domains. Titin may

Carol C Gregorio; Henk Granzier; Hiroyuki Sorimachi; Siegfried Labeit

1999-01-01

299

Corner-cutting mining assembly  

DOEpatents

A mining assembly includes a primary rotary cutter mounted on one end of a support shaft and four secondary rotary cutters carried on the same support shaft and positioned behind the primary cutters for cutting corners in the hole cut by the latter.

Bradley, John A. (San Antonio, TX)

1983-01-01

300

IFAS FACULTY ASSEMBLY EXECUTIVE COMMITTEE  

E-print Network

Members Present: Art Teixeira, Mike Kane, Bill Lindberg, Phil Kaufman, Nicole Stedman, Keith Schneider) ­ Keith Schneider gave report for Steve Futch. The IRC Committee has not met since the last FA meeting prior to the next assembly meeting on October 30. 3. Curriculum Committee (Phil Kaufman

Jawitz, James W.

301

IFAS FACULTY ASSEMBLY EXECUTIVE COMMITTEE  

E-print Network

IFAS FACULTY ASSEMBLY EXECUTIVE COMMITTEE JANUARY 10, 2013 3:30 ­ 4:30 PM 122 FRASIER ROGERS HALL Members Present: Art Teixeira, Mike Kane, Bill Lindberg, Phil Kaufman, Nicole Stedman, Steve Futch committee. #12;STANDING COMMITTEE REPORTS 1. IRC (Infrastructure and Resources Committee)­Steve Futch 2

Jawitz, James W.

302

IFAS FACULTY ASSEMBLY EXECUTIVE COMMITTEE  

E-print Network

IFAS FACULTY ASSEMBLY EXECUTIVE COMMITTEE AUGUST 30, 2012 1:30 ­ 3:00 PM 122 FRASIER ROGERS HALL (Infrastructure and Resources Committee) ­ Steve Futch - IRC discussed and accepted minutes of IRC meeting as submitted - Steve will present a brief report of the annual activities from last year (B. Lindberg chair

Jawitz, James W.

303

Pattern fuel assembly loading system  

SciTech Connect

This patent describes an interactive system for facilitating preloading of fuel rods into magazines, which comprises: an operator work station adapted for positioning between a supply of fuel rods of predetermined types, and the magazine defining grid locations for a predetermined fuel assembly; display means associated with the work station; scanner means associated with the work station and adapted for reading predetermined information accompanying the fuel rods; a rectangular frame adapted for attachment to one end of the fuel assembly loading magazine; prompter/detector means associated with the frame for detecting insertion of a fuel rod into the magazine; and processing means responsive to the scanner means and the sensing means for prompting the operator via the display means to pre-load the fuel rods into desired grid locations in the magazine. An apparatus is described for facilitating pre-loading of fuel rods in predetermined grid locations of a fuel assembly loading magazine, comprising: a rectangular frame adapted for attachment to one end of the fuel assembly loading magazine; and means associated with the frame for detecting insertion of fuel rods into the magazine.

Ahmed, H.J.; Gerkey, K.S.; Miller, T.W.; Wylie, M.E.

1986-12-02

304

49 CFR 572.112 - Head assembly.  

Code of Federal Regulations, 2011 CFR

...HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES Side Impact Hybrid Dummy 50th Percentile Male § 572.112 Head assembly. The head assembly consists of the head (drawing...

2011-10-01

305

49 CFR 572.113 - Neck assembly.  

Code of Federal Regulations, 2011 CFR

...HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES Side Impact Hybrid Dummy 50th Percentile Male § 572.113 Neck assembly. The head/neck assembly consists of the parts...

2011-10-01

306

Solder self-assembly for MEMS fabrication  

E-print Network

This thesis examines and demonstrates self-assembly of MEMS components on the 25 micron scale onto substrates using the capillary force of solder. This is an order of magnitude smaller than current solder self-assembly in ...

Au, Hin Meng, 1977-

2004-01-01

307

Varactor diode assembly with low parasitic reactances  

NASA Technical Reports Server (NTRS)

Development of varactor diode assembly overcomes parasitic reactances of conventional varactor packages. In specially constructed assembly very high idler-frequency to signal-frequency ratios are used to obtain low-noise operation over maximum bandwidth.

Dickens, L. E.

1975-01-01

308

Transplanting assembly of individual carbon nanotubes  

E-print Network

Handling and assembling individual nanostructures to bigger scale systems such as MEMS have been the biggest challenge. A deterministic assembly of individual carbon nanotubes by transplanting them to MEMS structures is ...

Kim, Soohyung

2009-01-01

309

Timelapse: Webb's Ambient Optical Assembly Stand  

NASA Video Gallery

The clean room at NASA's Goddard Space Flight Center in Greenbelt, Md., has received a giant structural steel frame called "AOAS," the Ambient Optical Assembly Stand that will be used to assemble t...

310

Development of Audio Transducer Helmet Assembly.  

National Technical Information Service (NTIS)

The program objective is the development of an Audio Transducer Helmet Assembly to be used in the Army Air Crewman Helmet. The Assembly includes earphones mounted in attenuating earcups along with auxiliary hardware, wiring and ancillary devices. A furthe...

A. J. Rosenheck, A. L. DiMattia

1967-01-01

311

In-space assembly-servicing requirements  

NASA Technical Reports Server (NTRS)

A method for developing the requirements for in-space assembly, servicing, and checkout of the proposed Mars space transfer vehicles is discussed. Required in-space operations and functions are identified in relation to various Earth to Orbit (ETO) vehicles by looking at the manifesting options of baseline Mars Space Transfer Vehicles (STV). Each operation is then reduced to a minimum complexity state resulting in a set of operational primitive functions. These primitive functions are used to assess the tradeoffs between robotic, telerobotic, and EVA operations. The study demonstrates that the complexity of the in-space operations remains stable with ETO vehicle size, and therefore the functions, and ultimately the infrastructure required to support proposed missions, are relatively unaffected by varying the ETO vehicle size within the range considered for this study.

Cockrell, Charles E.

1993-01-01

312

Subunit composition of a bicomponent toxin: Staphylococcal leukocidin forms an octameric transmembrane pore  

Microsoft Academic Search

Staphylococcal leukocidin pores are formed by the obligatory interaction of two distinct polypeptides, one of class F and one of class S, making them unique in the family of -barrel pore-forming toxins (-PFTs). By contrast, other -PFTs form homo-oligomeric pores; for example, the staphylococcal -hemolysin (HL) pore is a homoheptamer. Here, we deduce the subunit composition of a leukocidin pore

GEORGE MILES; LIVIU MOVILEANU; HAGAN BAYLEY

2002-01-01

313

Synthesis and solid-state study of supramolecular host-guest assemblies: Bis[6-O,6-O'-(1,2:3,4-diisopropylidene-alpha-D-galactopyranosyl)thiophosphoryl] dichalcogenides.  

PubMed

A complementary approach for studying structural details of complex solid materials formed by symmetrical and unsymmetrical dichalcogenides, which employs both X-ray diffraction (XRD) and solid-state NMR (SS NMR), is presented. The new diagnostic technique allows reversible crystallographic space group change and very subtle distortion of host geometry to be followed during guest migration in the crystal lattice. Bis[6-O,6-O'-(1,2:3,4-diisopropylidene-alpha-D-galactopyranosyl)]thiophosphoryl selenenyl sulfide, a representative of wheel-and-axle host (WAAH) molecules, can be synthesized in the solid state by grinding and gentle heating of disulfide 1 and diselenide 2. Full characterization of disulfide 1 in the solid phase has been reported (J. Org. Chem. 1995, 60, 2549). In the current work, the synthesis and both XRD and SS NMR studies of the isostructural diselenide substrate 2 are presented. A (31)P cross polarization magic angle spinning experiment is employed to follow the progress of synthesis of selenenyl sulfide 3 in the solid state. It is concluded that selenenyl sulfide exists in equilibrium with disulfide and diselenide in a 1:1:1 ratio in both the liquid and the powdered solid. A mixture of isostructural dichalcogenides crystallized from different solvents form three-component host-guest inclusion complexes with columnar architecture. In the host-guest complex of diselenide 2 with toluene (space group C2), columns of host molecules are in parallel orientations along all the axes, whereas in the structures of diselenide 2 with propan-2-ol and propan-1-ol (space group P3 2), the columns of host molecules lay along the 3-fold symmetry axis. Thermal processes effecting structural changes in the host lattice and the kinetics of reversible guest molecule diffusion were investigated using SS NMR spectroscopy. Finally, the Se/S scrambling phenomenon and limitations in the X-ray structure refinement of organic compounds containing selenium and sulfur in chains are discussed. PMID:18507446

Potrzebowski, Marek J; Potrzebowski, Wojciech M; Jeziorna, Agata; Ciesielski, Wlodzimierz; Gajda, Jaros?aw; Bujacz, Grzegorz D; Chruszcz, Maksymilian; Minor, Wladek

2008-06-20

314

Assembling DNA fragments with parallel algorithms  

Microsoft Academic Search

As more research centers embark on sequencing new genomes, the problem of DNA fragment assembly for shotgun sequencing is growing in importance and complexity. Accurate and fast assembly is a crucial part of any sequencing project and since the DNA fragment assembly problem is NP-hard, exact solutions are very difficult to obtain. Various heuristics, including genetic algorithms, were designed for

Enrique Alba; Gabriel Luque; Sami Khuri

2005-01-01

315

Algorithm for genome contig assembly. Final report  

SciTech Connect

An algorithm was developed for genome contig assembly which extended the range of data types that could be included in assembly and which ran on the order of a hundred times faster than the algorithm it replaced. Maps of all existing cosmid clone and YAC data at the Human Genome Information Resource were assembled using ICA. The resulting maps are summarized.

NONE

1995-09-01

316

Self-Assembly: How Nature Builds  

ERIC Educational Resources Information Center

Self-assembly or spontaneous assembly is a process in which materials build themselves without assistance. This process plays a central role in the construction of biological structures and materials such as cells, viruses, and bone, and also in abiotic processes like phase transitions and crystal formation. The principles of self-assembly help…

Jones, M. Gail; Falvo, Michael R.; Broadwell, Bethany; Dotger, Sharon

2006-01-01

317

Mini-Brayton heat source assembly development  

NASA Technical Reports Server (NTRS)

The work accomplished on the Mini-Brayton Heat Source Assembly program is summarized. Required technologies to design, fabricate and assemble components for a high temperature Heat Source Assembly (HSA) which would generate and transfer the thermal energy for a spaceborne Brayton Isotope Power System (BIPS) were developed.

Wein, D.; Zimmerman, W. F.

1978-01-01

318

Nuclear control rod position indicating assembly  

Microsoft Academic Search

The position of a control rod located within a nuclear reactor is sensed by an externally located position indicating assembly. The assembly includes a reed switch voltage divider circuit in which the individual reed switches are actuated in a 2-3-2-3 sequence by the magnetic field of a permanent magnet mounted to the control rod. The assembly averages the signals from

M. K. Foxworthy; J. T. Houston; B. D. Ziels

1977-01-01

319

The Archimedes 2 mechanical assembly planning system  

Microsoft Academic Search

We describe the implementation and performance of Archimedes 2, an integrated mechanical assembly planning system. Archimedes 2 includes two planners, two assembly sequence animation facilities, and an associated robotic workcell. Both planners use fully 3 dimensional data. A rudimentary translator from high level assembly plans to control code for the robotic workcell has also been implemented. We can translate data

S. G. Kaufmann; R. H. Wilson; R. E. Jones; T. L. Calton; A. L. Ames

1996-01-01

320

UNC Faculty Assembly Reports to the Faculty Senate Andrew Morehead, Faculty Assembly Delegate  

E-print Network

Model for Enrollment Expansion, Delaware Study on Teaching Workload and Delaware Faculty TeachingUNC Faculty Assembly Reports to the Faculty Senate Andrew Morehead, Faculty Assembly Delegate Report on January 17, 2014, UNC Faculty Assembly Meeting. Andrew Morehead, Faculty Assembly Delegate

321

Self-Assembling Behavior and Inhibition Effect of Dodecanethiol Self-Assembled Monolayers on Copper Surface  

NASA Astrophysics Data System (ADS)

The self-assembling behavior and inhibition effect of dodecanethiol self-assembled monolayers (SAMs) on copper surface were investigated by atomic force microscopy (AFM) and electrochemical methods. The assembling process was monitored by AFM phase images. The assembling time influences the corrosion protection efficiency of dodecanethiol SAMs. Surface friction significantly decreases when the copper surface is covered by SAMs.

Zhang, Xiulan; Zhang, Heng; Yang, Yihong; Chen, Zhenyu

2013-08-01

322

Free energy profile and mechanism of self-assembly of peptide amphiphiles based on a collective assembly coordinate.  

PubMed

By combining targeted molecular dynamics (TMD) simulations, umbrella sampling, and the weighted histogram analysis method (WHAM), we have calculated the potential of mean force (PMF) for the transition between the bound and free states of 90 peptide amphiphiles (PAs) in aqueous solution, with the bound state corresponding to a cylindrical micelle fiber. We specifically consider a collective reaction coordinate, the radius of gyration of the PAs, to describe assembly in this work. It is found that the free energy, enthalpy, and entropy differences between the free and bound states are -126 kcal/mol, -185 kcal/mol, and -190 cal/(mol K), respectively, for the self-assembly process. This indicates that the driving force to form the micelle structure is enthalpic. The enthalpic driving forces originate from several factors, including the conformational energy of PAs and the electrostatic and van der Waals interaction energy between solvent molecules and between solvent and PAs. Among these interactions, the solvent electrostatic interaction is the dominating one, contributing 54% of the total driving force. The PMF profile can be recognized as involving two stages of assembly: (1) PAs initially approach each other in mostly random configurations and loosely aggregate, resulting in significant desolvation and initiation of head-tail conformational reorganization; (2) PAs undergo a conformational disorder-to-order transition, including forming secondary structures that include more ?-sheets and fewer random coils, along with tail-head core-shell alignment and condensation that leads to total exclusion of water from the core. The PMF decreases slowly in the first stage, but rapidly in the second. This study demonstrates a hierarchy of assembly steps in which PA structural changes, solvation, and redistribution of solvent molecules play significant roles in the PA self-assembly process. PMID:23822638

Yu, Tao; Schatz, George C

2013-08-01

323

Assembly of synthetic cellulose I.  

PubMed Central

Cellulose microfibrils with an electron diffraction pattern characteristic of crystalline native cellulose I have been assembled abiotically by means of a cellulase-catalyzed polymerization of beta-cellobiosyl fluoride substrate monomer in acetonitrile/acetate buffer. Substantial purification of the Trichoderma viride cellulase enzyme was found to be essential for the formation of the synthetic cellulose I allomorph. Assembly of synthetic cellulose I appears to be a result of a micellar aggregation of the partially purified enzyme and the substrate in an organic/aqueous solvent system favoring the alignment of glucan chains with the same polarity and extended chain conformation, resulting in crystallization to form the metastable cellulose I allomorph. Images PMID:7519776

Lee, J H; Brown, R M; Kuga, S; Shoda, S; Kobayashi, S

1994-01-01

324

Automated array assembly, phase 2  

NASA Technical Reports Server (NTRS)

Tasks of scaling up the tandem junction cell (TJC) from 2 cm x 2 cm to 6.2 cm and the assembly of several modules using these large area TJC's are described. The scale-up of the TJC was based on using the existing process and doing the necessary design activities to increase the cell area to an acceptably large area. The design was carried out using available device models. The design was verified and sample large area TJCs were fabricated. Mechanical and process problems occurred causing a schedule slippage that resulted in contract expiration before enough large-area TJCs were fabricated to populate the sample tandem junction modules (TJM). A TJM design was carried out in which the module interconnects served to augment the current collecting buses on the cell. No sample TJMs were assembled due to a shortage of large-area TJCs.

Carbajal, B. G.

1979-01-01

325

BIOCHEMISTRY: An Enzyme Assembly Line  

NSDL National Science Digital Library

Access to the article is free, however registration and sign-in are required. Fatty acid synthases and related megaenzymes are highly adaptable to new functions as a result of their modular architecture. The fundamental polymers of biology--proteins, DNA, and RNA--are products of repetitive condensation of simple amino acid or nucleotide building blocks and are comparatively easy to assemble. However, other biomolecules require additional reactions beyond condensation of building blocks. Examples are the fatty acids and the polyketide and nonribosomal peptide secondary metabolites. These molecules are produced by complex enzyme assembly lines that include multiple catalytic domains. Two new crystal structures--one reported recently (1), the other by Maier et al. on page 1315 of this issue (2)--enrich our understanding of how these mega-enzymes function as efficient factories to produce a remarkable range of metabolic products.

Janet L. Smith (University of Michigan;Life Sciences Institute; Department of Biological Chemistry); David H. Sherman (University of Michigan;Life Sciences Institute; Departments of Medicinal Chemistry, Chemistry, and Microbiology and Immunology)

2008-09-05

326

Downhole tool inflatable packer assembly  

SciTech Connect

A downhole tool inflatable packer assembly includes an upper packer shoe having a bypass mandrel connected thereto. A packer mandrel adapter has an upper end connected to a lower end of the bypass mandrel. A mandrel cover tube extends downwardly from the packer mandrel adapter. A packer mandrel has an upper portion connected to the packer mandrel adapter. A flow connector and a lower packer adapter are connected in that order below the packer mandrel. A packer flow tube has an upper end received in the bypass mandrel and a lower end received in the flow connector. An inflatable bladder has an upper end connected to the upper packer shoe and a lower end connected to a floating packer shoe which slidably engages the mandrel cover tube. A central flow passage, a packer bypass passage, and an inflation passage are disposed in the packer assembly.

Brandell, J.T.

1984-07-10

327

Oxygen Generation Assembly Technology Development  

NASA Technical Reports Server (NTRS)

Hamilton Standard Space Systems International (HSSI) is under contract to NASA Marshall Space Flight Center (MSFC) to develop an Oxygen Generation Assembly (OGA) for the International Space Station (ISS). The International Space Station Oxygen Generation Assembly (OGA) electrolyzes potable water from the Water Recovery System (WRS) to provide gaseous oxygen to the Space Station module atmosphere. The OGA produces oxygen for metabolic consumption by crew and biological specimens. The OGA also replenishes oxygen lost by experiment ingestion, airlock depressurization, CO2 venting, and leakage. As a byproduct, gaseous hydrogen is generated. The hydrogen will be supplied at a specified pressure range above ambient to support future utilization. Initially, the hydrogen will be vented overboard to space vacuum. This paper describes the OGA integration into the ISS Node 3. It details the development history supporting the design and describes the OGA System characteristics and its physical layout.

Bagdigian, Robert; Cloud, Dale

1999-01-01

328

Nanobiocatalytic assemblies for artificial photosynthesis.  

PubMed

Natural photosynthesis, a solar-to-chemical energy conversion process, occurs through a series of photo-induced electron transfer reactions in nanoscale architectures that contain light-harvesting complexes, protein-metal clusters, and many redox biocatalysts. Artificial photosynthesis in nanobiocatalytic assemblies aims to reconstruct man-made photosensitizers, electron mediators, electron donors, and redox enzymes for solar synthesis of valuable chemicals through visible light-driven cofactor regeneration. The key requirement in the design of biocatalyzed artificial photosynthetic process is an efficient and forward electron transfer between each photosynthetic component. This review describes basic principles in combining redox biocatalysis with photocatalysis, and highlights recent research outcomes in the development of nanobiocatalytic assemblies that can mimic natural photosystems I and II, respectively. Current issues in biocatalyzed artificial photosynthesis and future perspectives will be briefly discussed. PMID:24832068

Kim, Jae Hong; Nam, Dong Heon; Park, Chan Beum

2014-08-01

329

AGORA: Assembly Guided by Optical Restriction Alignment  

PubMed Central

Background Genome assembly is difficult due to repeated sequences within the genome, which create ambiguities and cause the final assembly to be broken up into many separate sequences (contigs). Long range linking information, such as mate-pairs or mapping data, is necessary to help assembly software resolve repeats, thereby leading to a more complete reconstruction of genomes. Prior work has used optical maps for validating assemblies and scaffolding contigs, after an initial assembly has been produced. However, optical maps have not previously been used within the genome assembly process. Here, we use optical map information within the popular de Bruijn graph assembly paradigm to eliminate paths in the de Bruijn graph which are not consistent with the optical map and help determine the correct reconstruction of the genome. Results We developed a new algorithm called AGORA: Assembly Guided by Optical Restriction Alignment. AGORA is the first algorithm to use optical map information directly within the de Bruijn graph framework to help produce an accurate assembly of a genome that is consistent with the optical map information provided. Our simulations on bacterial genomes show that AGORA is effective at producing assemblies closely matching the reference sequences. Additionally, we show that noise in the optical map can have a strong impact on the final assembly quality for some complex genomes, and we also measure how various characteristics of the starting de Bruijn graph may impact the quality of the final assembly. Lastly, we show that a proper choice of restriction enzyme for the optical map may substantially improve the quality of the final assembly. Conclusions Our work shows that optical maps can be used effectively to assemble genomes within the de Bruijn graph assembly framework. Our experiments also provide insights into the characteristics of the mapping data that most affect the performance of our algorithm, indicating the potential benefit of more accurate optical mapping technologies, such as nano-coding. PMID:22856673

2012-01-01

330

Assembling the Skylab Orbital Workshop  

NASA Technical Reports Server (NTRS)

This photograph was taken during assembly of the bottom and upper floors of the Skylab Orbital Workshop (OWS). The OWS was divided into two major compartments. The lower level provided crew accommodations for sleeping, food preparation and consumption, hygiene, waste processing and disposal, and performance of certain experiments. The upper level consisted of a large work area and housed water storage tanks, a food freezer, storage vaults for film, scientific airlocks, mobility and stability experiment equipment, and other experimental equipment.

1970-01-01

331

Water Processor Assembly Technology Development  

NASA Technical Reports Server (NTRS)

The International Space Station (ISS) Water Processor Assembly (WPA) produces potable quality water from humidity condensate, carbon dioxide reduction water, water obtained from fuel cells, reclaimed urine distillate, shower, handwash and oral hygiene waste waters. This paper describes the WPA integration into the ISS Node 3. It details the substantial development history supporting the design and describes the WPA System characteristics and its physical layout.

Bagdigian, Robert; Parker, Dave; OConnor, Ed

1999-01-01

332

Vibrational spectroscopy of supermolecular assemblies  

Microsoft Academic Search

Vibrational spectroscopy as a tool for ultrathin organic film structural investigations is considered. The application of total-internal-reflection-excited surface Raman spectroscopy to self-assembled and Langmuir-Blodgett monolayers and multilayer structures is described. The substrate is fused silica upon which a metallic mask has been deposited. Laser excitation is on-coupled from the rear through the ~100-?m opening in the mask. A metal island

D. J. Walls; K. Hughes; P. W. Bohn

1989-01-01

333

Structural Assembly Demonstration Experiment (SADE)  

NASA Technical Reports Server (NTRS)

The purpose of the Structural Assembly Demonstration Experiment (SADE) was to create a near-term Shuttle flight experiment focusing on the deployment and erection of structural truss elements. The activities of the MIT Space Systems Laboratory consist of three major areas: preparing and conducting neutral buoyancy simulation test series; producing a formal SADE Experiment plan; and studying the structural dynamics issues of the truss structure. Each of these areas is summarized.

Akin, David L.; Mills, Raymond A.; Bowden, Mary L.

1987-01-01

334

Rotor assembly and assay method  

DOEpatents

A rotor assembly for carrying out an assay includes a rotor body which is rotatable about an axis of rotation, and has a central chamber and first, second, third, fourth, fifth, and sixth chambers which are in communication with and radiate from the central chamber. The rotor assembly further includes a shuttle which is movable through the central chamber and insertable into any of the chambers, the shuttle including a reaction cup carrying an immobilized antigen or an antibody for transport among the chambers. A method for carrying out an assay using the rotor assembly includes moving the reaction cup among the six chambers by passing the cup through the central chamber between centrifugation steps in order to perform the steps of: separating plasma from blood cells, binding plasma antibody or antigen, washing, drying, binding enzyme conjugate, reacting with enzyme substrate and optically comparing the resulting reaction product with unreacted enzyme substrate solution. The movement of the reaction cup can be provided by attaching a magnet to the reaction cup and supplying a moving magnetic field to the rotor.

Burtis, Carl A. (Oak Ridge, TN); Johnson, Wayne F. (Loudon, TN); Walker, William A. (Knoxville, TN)

1993-01-01

335

Automated solar module assembly line  

NASA Technical Reports Server (NTRS)

The solar module assembly machine which Kulicke and Soffa delivered under this contract is a cell tabbing and stringing machine, and capable of handling a variety of cells and assembling strings up to 4 feet long which then can be placed into a module array up to 2 feet by 4 feet in a series of parallel arrangement, and in a straight or interdigitated array format. The machine cycle is 5 seconds per solar cell. This machine is primarily adapted to 3 inch diameter round cells with two tabs between cells. Pulsed heat is used as the bond technique for solar cell interconnects. The solar module assembly machine unloads solar cells from a cassette, automatically orients them, applies flux and solders interconnect ribbons onto the cells. It then inverts the tabbed cells, connects them into cell strings, and delivers them into a module array format using a track mounted vacuum lance, from which they are taken to test and cleaning benches prior to final encapsulation into finished solar modules. Throughout the machine the solar cell is handled very carefully, and any contact with the collector side of the cell is avoided or minimized.

Bycer, M.

1980-01-01

336

Automated assembly of VECSEL components  

NASA Astrophysics Data System (ADS)

Due to the architectural advantage of an external cavity architecture that enables the integration of additional elements into the cavity (e.g. for mode control, frequency conversion, wavelength tuning or passive mode-locking) VECSELs are a rapidly developing laser technology. Nevertheless they often have to compete with direct (edge) emitting laser diodes which can have significant cost advantages thanks to their rather simple structure and production processes. One way to compensate the economical disadvantages of VECSELs is to optimize each component in terms of quality and costs and to apply more efficient (batch) production processes. In this context, the paper presents recent process developments for the automated assembly of VECSELs using a new type of desktop assembly station with an ultra-precise micromanipulator. The core concept is to create a dedicated process development environment from which implemented processes can be transferred fluently to production equipment. By now two types of processes have been put into operation on the desktop assembly station: 1.) passive alignment of the pump optics implementing a camera-based alignment process, where the pump spot geometry and position on the semiconductor chip is analyzed and evaluated; 2.) active alignment of the end mirror based on output power measurements and optimization algorithms. In addition to the core concept and corresponding hardware and software developments, detailed results of both processes are presented explaining measurement setups as well as alignment strategies and results.

Brecher, C.; Pyschny, N.; Haag, S.; Mueller, T.

2013-02-01

337

Genome Sequence Databases (Overview): Sequencing and Assembly  

SciTech Connect

From the date its role in heredity was discovered, DNA has been generating interest among scientists from different fields of knowledge: physicists have studied the three dimensional structure of the DNA molecule, biologists tried to decode the secrets of life hidden within these long molecules, and technologists invent and improve methods of DNA analysis. The analysis of the nucleotide sequence of DNA occupies a special place among the methods developed. Thanks to the variety of sequencing technologies available, the process of decoding the sequence of genomic DNA (or whole genome sequencing) has become robust and inexpensive. Meanwhile the assembly of whole genome sequences remains a challenging task. In addition to the need to assemble millions of DNA fragments of different length (from 35 bp (Solexa) to 800 bp (Sanger)), great interest in analysis of microbial communities (metagenomes) of different complexities raises new problems and pushes some new requirements for sequence assembly tools to the forefront. The genome assembly process can be divided into two steps: draft assembly and assembly improvement (finishing). Despite the fact that automatically performed assembly (or draft assembly) is capable of covering up to 98% of the genome, in most cases, it still contains incorrectly assembled reads. The error rate of the consensus sequence produced at this stage is about 1/2000 bp. A finished genome represents the genome assembly of much higher accuracy (with no gaps or incorrectly assembled areas) and quality ({approx}1 error/10,000 bp), validated through a number of computer and laboratory experiments.

Lapidus, Alla L.

2009-01-01

338

Dynamic pathways for viral capsid assembly  

SciTech Connect

We develop a class of models with which we simulate the assembly of particles into T1 capsid-like objects using Newtonian dynamics. By simulating assembly for many different values of system parameters, we vary the forces that drive assembly. For some ranges of parameters, assembly is facile, while for others, assembly is dynamically frustrated by kinetic traps corresponding to malformed or incompletely formed capsids. Our simulations sample many independent trajectories at various capsomer concentrations, allowing for statistically meaningful conclusions. Depending on subunit (i.e., capsomer) geometries, successful assembly proceeds by several mechanisms involving binding of intermediates of various sizes. We discuss the relationship between these mechanisms and experimental evaluations of capsid assembly processes.

Hagan, Michael F.; Chandler, David

2006-02-09

339

Deterministic nanoparticle assemblies: from substrate to solution  

NASA Astrophysics Data System (ADS)

The deterministic assembly of metallic nanoparticles is an exciting field with many potential benefits. Many promising techniques have been developed, but challenges remain, particularly for the assembly of larger nanoparticles which often have more interesting plasmonic properties. Here we present a scalable process combining the strengths of top down and bottom up fabrication to generate deterministic 2D assemblies of metallic nanoparticles and demonstrate their stable transfer to solution. Scanning electron and high-resolution transmission electron microscopy studies of these assemblies suggested the formation of nanobridges between touching nanoparticles that hold them together so as to maintain the integrity of the assembly throughout the transfer process. The application of these nanoparticle assemblies as solution-based surface-enhanced Raman scattering (SERS) materials is demonstrated by trapping analyte molecules in the nanoparticle gaps during assembly, yielding uniformly high enhancement factors at all stages of the fabrication process.

Barcelo, Steven J.; Kim, Ansoon; Gibson, Gary A.; Norris, Kate J.; Yamakawa, Mineo; Li, Zhiyong

2014-04-01

340

Constraint-based interactive assembly planning  

SciTech Connect

The constraints on assembly plans vary depending on the product, assembly facility, assembly volume, and many other factors. This paper describes the principles and implementation of a framework that supports a wide variety of user-specified constraints for interactive assembly planning. Constraints from many sources can be expressed on a sequencing level, specifying orders and conditions on part mating operations in a number of ways. All constraints are implemented as filters that either accept or reject assembly operations proposed by the planner. For efficiency, some constraints are supplemented with special-purpose modifications to the planner`s algorithms. Replanning is fast enough to enable a natural plan-view-constrain-replan cycle that aids in constraint discovery and documentation. We describe an implementation of the framework in a computer-aided assembly planning system and experiments applying the system to several complex assemblies. 12 refs., 2 figs., 3 tabs.

Jones, R.E.; Wilson, R.H.; Calton, T.L.

1997-03-01

341

Gel-to-fluid phase transformations in solid-supported phospholipid bilayers assembled by the Langmuir-Blodgett technique: effect of the Langmuir monolayer phase state and molecular density.  

PubMed

Planar-supported phospholipid bilayers are increasingly used as synthetic membranes for scientific and practical applications. The thermotropic phase properties of supported bilayers are important for recreating biologically relevant situations. Unlike free-standing lipid membranes that undergo one gel-to-fluid or main phase transition, mica-supported single bilayers have been found to undergo two separate leaflet transitions. Although the distinctive nature of the main transition in mica-supported bilayers has been attributed to different effects, determining their relevance has been problematic because vesicle fusion, the technique most widely used to prepare solid-supported bilayer membranes, does not allow one to readily control the lipid surface coverage and molecular density. To circumvent the limitations of the vesicle fusion method and systematically investigate the effects on the individual leaflet transitions of the lipid phase state and molecular density before deposition on the substrate, mica-supported single bilayers of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) were prepared using the Langmuir-Blodgett technique. The gel-to-fluid transitions of the bilayer leaflets were tracked by controlled-temperature atomic force microscopy to determine the relative fractions of the gel and fluid phases as a function of temperature. The fraction of solid versus temperature data was fit to the van't Hoff equation to determine the leaflet melting temperatures and transition enthalpies. The phase state and molecular density of the Langmuir monolayer precursor at the transfer pressure of 35 mN m(-1) was found to have a greater effect on the main transition temperature and width of the distal (upper) leaflet than that of the proximal (lower) one. The contributions of substrate-mediated condensation, asymmetric lipid densities, and surface area available for thermal expansion of the bilayer are addressed. This work demonstrates the potential of the Langmuir-Blodgett technique as a tool for identifying and manipulating the factors that govern the phase transition properties of surface-confined lipid bilayers. PMID:25059993

Ramkaran, Mohini; Badia, Antonella

2014-08-14

342

Assembly of Colloidal Materials Using Bioadhesive Interactions  

NASA Technical Reports Server (NTRS)

We have pursued the use of biological crosslinking molecules of several types to make colloidal materials at relatively low volume fraction of colloidal particles. The objective is to make binary alloys of colloidal particles, made of two different colloidal particles coated with complementary biological lock-and-key binding molecules, which assemble due to the biological specificity. The long-term goal is to use low affinity lock-and-key biological interactions, so that the can anneal to form crystalline states. We have used a variety of different surface chemistries in order to make colloidal materials. Our first system involved using selectin-carbohydrate (sialyl-Lewis) interactions; this chemistry is derived from immune system. This chemical interaction is of relatively low affinity, with timescales for dissociation of several seconds. Furthermore, the adhesion mediated by these molecules can be reversed by the chelation of calcium atoms; thus assembled structures can be disassembled reversibly. Our second system employed avidin-biotin chemistry. This well-studied system is of high affinity, and is generally irreversible on a laboratory time-scale. Thus, we would expect selectin-carbohydrate interactions at high molecular density and avidin-biotin interactions to give kinetically-trapped structures; however, at low densities, we would expect significant differences in the structure and dynamics of the two materials, owing to their very different release rates. We have also begun to use a third chemistry - DNA hybridization. By attaching single stranded DNA oligonucleotide chains to beads, we can drive the assembly of colloidal materials by hybridization of complementary DNA chains. It is well known that DNA adenosine-thymine (A-T) and guanine-cytosine (G-C) bases hybridize pairwise with a Gibbs free energy change of 1.7 kcal/mol per base; thus, the energy of the assembly can be modulated by altering the number of complementary bases in the DNA chains. Using these different crosslinking molecules, we have assembled colloidal materials from different-sized colloidal particles, A and B. In the first sets of experiment, we used high densities of adhesion molecules, and 0.96 micron (A) and 5.5 micron (B) diameter particles. The high density of adhesion molecules means that the structures are kinetically trapped in nonequilibrium configurations. The structure of the suspension can be varied by changing the number ratio of the two types of colloidal particles, NA and NB, where A is the smaller particle. With carbohydrate-selectin or avidin-biotin interactions, large NA/NB leads to the formation of colloidal micelles, with the large center B particle surrounded by many smaller A particles. As the ratio NA/NB decreases, the structures become more extended, approaching the formation of macro-Rouse polymers - extended linear chains where A beads are connected with intervening small B linkers.

Hammer, Daniel A.; Hiddessen, Amy L.; Tohver, Valeria; Crocker, John C.; Weitz, David A.

2002-01-01

343

Lighting up cells with lanthanide self-assembled helicates  

PubMed Central

Lanthanide bioprobes and bioconjugates are ideal luminescent stains in view of their low propensity to photobleaching, sharp emission lines and long excited state lifetimes permitting time-resolved detection for enhanced sensitivity. We show here how the interplay between physical, chemical and biochemical properties allied to microfluidics engineering leads to self-assembled dinuclear lanthanide luminescent probes illuminating live cells and selectively detecting biomarkers expressed by cancerous human breast cells. PMID:24511387

Bunzli, Jean-Claude G.

2013-01-01

344

Spatial Extent of Charge Repulsion Regulates Assembly Pathways for Lysozyme Amyloid Fibrils  

PubMed Central

Formation of large protein fibrils with a characteristic cross ?-sheet architecture is the key indicator for a wide variety of systemic and neurodegenerative amyloid diseases. Recent experiments have strongly implicated oligomeric intermediates, transiently formed during fibril assembly, as critical contributors to cellular toxicity in amyloid diseases. At the same time, amyloid fibril assembly can proceed along different assembly pathways that might or might not involve such oligomeric intermediates. Elucidating the mechanisms that determine whether fibril formation proceeds along non-oligomeric or oligomeric pathways, therefore, is important not just for understanding amyloid fibril assembly at the molecular level but also for developing new targets for intervening with fibril formation. We have investigated fibril formation by hen egg white lysozyme, an enzyme for which human variants underlie non-neuropathic amyloidosis. Using a combination of static and dynamic light scattering, atomic force microscopy and circular dichroism, we find that amyloidogenic lysozyme monomers switch between three different assembly pathways: from monomeric to oligomeric fibril assembly and, eventually, disordered precipitation as the ionic strength of the solution increases. Fibril assembly only occurred under conditions of net repulsion among the amyloidogenic monomers while net attraction caused precipitation. The transition from monomeric to oligomeric fibril assembly, in turn, occurred as salt-mediated charge screening reduced repulsion among individual charged residues on the same monomer. We suggest a model of amyloid fibril formation in which repulsive charge interactions are a prerequisite for ordered fibril assembly. Furthermore, the spatial extent of non-specific charge screening selects between monomeric and oligomeric assembly pathways by affecting which subset of denatured states can form suitable intermolecular bonds and by altering the energetic and entropic requirements for the initial intermediates emerging along the monomeric vs. oligomeric assembly path. PMID:21483680

Hill, Shannon E.; Miti, Tatiana; Richmond, Tyson; Muschol, Martin

2011-01-01

345

Combining Transcriptome Assemblies from Multiple De Novo Assemblers in the Allo-Tetraploid Plant Nicotiana benthamiana  

PubMed Central

Background Nicotiana benthamiana is an allo-tetraploid plant, which can be challenging for de novo transcriptome assemblies due to homeologous and duplicated gene copies. Transcripts generated from such genes can be distinct yet highly similar in sequence, with markedly differing expression levels. This can lead to unassembled, partially assembled or mis-assembled contigs. Due to the different properties of de novo assemblers, no one assembler with any one given parameter space can re-assemble all possible transcripts from a transcriptome. Results In an effort to maximise the diversity and completeness of de novo assembled transcripts, we utilised four de novo transcriptome assemblers, TransAbyss, Trinity, SOAPdenovo-Trans, and Oases, using a range of k-mer sizes and different input RNA-seq read counts. We complemented the parameter space biologically by using RNA from 10 plant tissues. We then combined the output of all assemblies into a large super-set of sequences. Using a method from the EvidentialGene pipeline, the combined assembly was reduced from 9.9 million de novo assembled transcripts to about 235,000 of which about 50,000 were classified as primary. Metrics such as average bit-scores, feature response curves and the ability to distinguish paralogous or homeologous transcripts, indicated that the EvidentialGene processed assembly was of high quality. Of 35 RNA silencing gene transcripts, 34 were identified as assembled to full length, whereas in a previous assembly using only one assembler, 9 of these were partially assembled. Conclusions To achieve a high quality transcriptome, it is advantageous to implement and combine the output from as many different de novo assemblers as possible. We have in essence taking the ‘best’ output from each assembler while minimising sequence redundancy. We have also shown that simultaneous assessment of a variety of metrics, not just focused on contig length, is necessary to gauge the quality of assemblies. PMID:24614631

Nakasugi, Kenlee; Crowhurst, Ross; Bally, Julia; Waterhouse, Peter

2014-01-01

346

MYBPH inhibits NM IIA assembly via direct interaction with NMHC IIA and reduces cell motility  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer MYBPH inhibits NMHC IIA assembly and cell motility. Black-Right-Pointing-Pointer MYBPH interacts to assembly-competent NM IIA. Black-Right-Pointing-Pointer MYBPH inhibits RLC and NMHC IIA, independent components of NM IIA. -- Abstract: Actomyosin filament assembly is a critical step in tumor cell migration. We previously found that myosin binding protein H (MYBPH) is directly transactivated by the TTF-1 lineage-survival oncogene in lung adenocarcinomas and inhibits phosphorylation of the myosin regulatory light chain (RLC) of non-muscle myosin IIA (NM IIA) via direct interaction with Rho kinase 1 (ROCK1). Here, we report that MYBPH also directly interacts with an additional molecule, non-muscle myosin heavy chain IIA (NMHC IIA), which was found to occur between MYBPH and the rod portion of NMHC IIA. MYBPH inhibited NMHC IIA assembly and reduced cell motility. Conversely, siMYBPH-induced increased motility was partially, yet significantly, suppressed by blebbistatin, a non-muscle myosin II inhibitor, while more profound effects were attained by combined treatment with siROCK1 and blebbistatin. Electron microscopy observations showed well-ordered paracrystals of NMHC IIA reflecting an assembled state, which were significantly less frequently observed in the presence of MYBPH. Furthermore, an in vitro sedimentation assay showed that a greater amount of NMHC IIA was in an unassembled state in the presence of MYBPH. Interestingly, treatment with a ROCK inhibitor that impairs transition of NM IIA from an assembly-incompetent to assembly-competent state reduced the interaction between MYBPH and NMHC IIA, suggesting that MYBPH has higher affinity to assembly-competent NM IIA. These results suggest that MYBPH inhibits RLC and NMHC IIA, independent components of NM IIA, and negatively regulates actomyosin organization at 2 distinct steps, resulting in firm inhibition of NM IIA assembly.

Hosono, Yasuyuki [Division of Molecular Carcinogenesis, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya 466-8550 (Japan)] [Division of Molecular Carcinogenesis, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya 466-8550 (Japan); Usukura, Jiro [Division of Integrated Project, EcoTopia Science Institute, Nagoya University, Chikusa-ku, Nagoya 464-8603 (Japan)] [Division of Integrated Project, EcoTopia Science Institute, Nagoya University, Chikusa-ku, Nagoya 464-8603 (Japan); Yamaguchi, Tomoya; Yanagisawa, Kiyoshi; Suzuki, Motoshi [Division of Molecular Carcinogenesis, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya 466-8550 (Japan)] [Division of Molecular Carcinogenesis, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya 466-8550 (Japan); Takahashi, Takashi, E-mail: tak@med.nagoya-u.ac.jp [Division of Molecular Carcinogenesis, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya 466-8550 (Japan)] [Division of Molecular Carcinogenesis, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya 466-8550 (Japan)

2012-11-09

347

Assemblathon 1: A competitive assessment of de novo short read assembly methods  

PubMed Central

Low-cost short read sequencing technology has revolutionized genomics, though it is only just becoming practical for the high-quality de novo assembly of a novel large genome. We describe the Assemblathon 1 competition, which aimed to comprehensively assess the state of the art in de novo assembly methods when applied to current sequencing technologies. In a collaborative effort, teams were asked to assemble a simulated Illumina HiSeq data set of an unknown, simulated diploid genome. A total of 41 assemblies from 17 different groups were received. Novel haplotype aware assessments of coverage, contiguity, structure, base calling, and copy number were made. We establish that within this benchmark: (1) It is possible to assemble the genome to a high level of coverage and accuracy, and that (2) large differences exist between the assemblies, suggesting room for further improvements in current methods. The simulated benchmark, including the correct answer, the assemblies, and the code that was used to evaluate the assemblies is now public and freely available from http://www.assemblathon.org/. PMID:21926179

Earl, Dent; Bradnam, Keith; St. John, John; Darling, Aaron; Lin, Dawei; Fass, Joseph; Yu, Hung On Ken; Buffalo, Vince; Zerbino, Daniel R.; Diekhans, Mark; Nguyen, Ngan; Ariyaratne, Pramila Nuwantha; Sung, Wing-Kin; Ning, Zemin; Haimel, Matthias; Simpson, Jared T.; Fonseca, Nuno A.; Birol, Inanc; Docking, T. Roderick; Ho, Isaac Y.; Rokhsar, Daniel S.; Chikhi, Rayan; Lavenier, Dominique; Chapuis, Guillaume; Naquin, Delphine; Maillet, Nicolas; Schatz, Michael C.; Kelley, David R.; Phillippy, Adam M.; Koren, Sergey; Yang, Shiaw-Pyng; Wu, Wei; Chou, Wen-Chi; Srivastava, Anuj; Shaw, Timothy I.; Ruby, J. Graham; Skewes-Cox, Peter; Betegon, Miguel; Dimon, Michelle T.; Solovyev, Victor; Seledtsov, Igor; Kosarev, Petr; Vorobyev, Denis; Ramirez-Gonzalez, Ricardo; Leggett, Richard; MacLean, Dan; Xia, Fangfang; Luo, Ruibang; Li, Zhenyu; Xie, Yinlong; Liu, Binghang; Gnerre, Sante; MacCallum, Iain; Przybylski, Dariusz; Ribeiro, Filipe J.; Yin, Shuangye; Sharpe, Ted; Hall, Giles; Kersey, Paul J.; Durbin, Richard; Jackman, Shaun D.; Chapman, Jarrod A.; Huang, Xiaoqiu; DeRisi, Joseph L.; Caccamo, Mario; Li, Yingrui; Jaffe, David B.; Green, Richard E.; Haussler, David; Korf, Ian; Paten, Benedict

2011-01-01

348

Solvent mediated self-assembly of solids  

SciTech Connect

Solvent-mediated crystallization represents a robust approach to self-assembly of nanostructures and microstructures. In organic systems, the relative ease with which the structure of hydrogen- bonded molecules can be manipulated allows for generation of a wide variety of nanoscale crystal structures. In living organisms, control over the micron-to-millimeter form of inorganic crystals is achieved through introduction of bio-organic molecules. The purpose of this proposal is to understand the interplay between solution chemistry, molecular structure, surface chemistry, and the processes of nucleation and crystal growth in solvent-mediated systems, with the goal of developing the atomic and molecular basis of a solvent-mediated self-assembly technology. We will achieve this purpose by: (1) utilizing an atomic force microscopy (AFM) approach that provides in situ, real time imaging during growth from solutions, (2) by modifying kinetic Monte Carlo (KMC) models to include solution-surface kinetics, (3) by introducing quantum chemistry (QC) calculations of the potentials of the relevant chemical species and the near-surface structure of the solution, and (4) by utilizing molecular dynamics (MD) simulations to identify the minimum energy pathways to the solid state. Our work will focus on two systems chosen to address both the manometer and micron-to-millimeter length scales of assembly, the family of 2,5- diketopiperazines (X-DKPs) and the system of CaCO{sub 3} with amino acids. Using AFM, we will record the evolution of surface morphology, critical lengths, step speeds, and step-step interactions as a function of supersaturation and temperature. In the case of the X-DKPs, these measurements will be repeated as the molecular structure of the growth unit is varied. In the case of CaCO{sub 3}, they will be performed as a function of solution chemistry including pH, ionic strength, and amino acid content. In addition, we will measure nucleation rates and orientations of CaCO{sub 3} on polyamino acid templates. From these measurements, we will extract fundamental growth parameters for input into KMC simulations whose predictions will in turn be compared to the experimental observations. The KMC simulations will incorporate atomic processes representing the minimum energy pathways as determined from the MD calculations. The interaction potentials of the relevant chemical species as well as the hydrated surface, including the electrochemical double layer, used in the MD simulations will be determined using coupled solutions to the Schrodinger and Poisson-Boltzmann equations which take account of electronic relaxation effects.

De Yoreo, J.; Wilson, W.D.; Palmore, T.

1997-12-12

349

Interfacial Assembly of Graphene Oxide Sheets  

NASA Astrophysics Data System (ADS)

Scientific interest in graphene oxide (GO) sheets, the product of chemical oxidation and exfoliation of graphite powder, has resurged in recent years because GO is considered a promising precursor for the bulk production of graphene-based sheets for a variety of applications. In addition, GO can be viewed as an unconventional type of soft material as it is characterized by two abruptly different length scales. Its thickness is of typical molecular dimensions, measured to be about 1 nm by atomic force microscopy, but its lateral dimensions are that of common colloidal particles, ranging from nanometers to tens of microns. This high anisotropy leads to interesting fundamental colloidal interactions between the soft sheets which have practical implications in the solution processing and assembly of the material. This research therefore aims to use a variety of techniques to control these inter-sheet interactions to gain an understanding of the processing-structure relationships which ultimately determine the overall properties of the bulk GO assembly. GO is identified as a two-dimensional amphiphile with a unique edge-to-center arrangement of hydrophilic and hydrophobic groups, which has led to the demonstration of its pH- and size-dependent surface activity. The water surface is then utilized, as in the Langmuir-Blodgett technique, as an ideal substrate to tile up the GO sheets and study the interactions between them. Sheet-sheet interaction morphologies were successfully altered between wrinkled and overlapped states by pH tuning of sheet charge density, and the resulting structure-property relationships are explored. In addition, a novel flash-reduction and assembly process is described in which a simple photographic camera flash can rapidly and cleanly turn an insulating, well-stacked GO paper to a more open and fluffy conducting film. Lastly, the use of these research results as educational outreach platforms is highlighted. A variety of outlets, such as YouTube videos, laboratory tours, e-mentoring, and module creation brought this research outside the scientific community to help inspire our next generation of scientists.

Cote, Laura J.

350

Self-Assembly of Collagen on Flat Surfaces: The Interplay of Collagen-Collagen and Collagen-Substrate Interactions  

E-print Network

Self-Assembly of Collagen on Flat Surfaces: The Interplay of Collagen-Collagen and Collagen, Washington 99352, United States ABSTRACT: Fibrillar collagens, common tissue scaffolds in live organisms, canH and the electrolyte concentration in solution largely control the collagen assembly, the physical reasons why

Ciobanu, Cristian

351

Design Parameters Influencing Reliability of CCGA Assembly: A Sensitivity Analysis  

NASA Technical Reports Server (NTRS)

Area Array microelectronic packages with small pitch and large I/O counts are now widely used in microelectronics packaging. The impact of various package design and materials/process parameters on reliability has been studied through extensive literature review. Reliability of Ceramic Column Grid Array (CCGA) package assemblies has been evaluated using JPL thermal cycle test results (-50(deg)/75(deg)C, -55(deg)/100(deg)C, and -55(deg)/125(deg)C), as well as those reported by other investigators. A sensitivity analysis has been performed using the literature da to study the impact of design parameters and global/local stress conditions on assembly reliability. The applicability of various life-prediction models for CCGA design has been investigated by comparing model's predictions with the experimental thermal cycling data. Finite Element Method (FEM) analysis has been conducted to assess the state of the stress/strain in CCGA assembly under different thermal cycling, and to explain the different failure modes and locations observed in JPL test assemblies.

Tasooji, Amaneh; Ghaffarian, Reza; Rinaldi, Antonio

2006-01-01

352

Self-Assembly of Globular Protein-Polymer Diblock Copolymers  

NASA Astrophysics Data System (ADS)

The self-assembly of globular protein-polymer diblock copolymers into nanostructured phases is demonstrated as an elegant and simple method for structural control in biocatalysis or bioelectronics. In order to fundamentally investigate self-assembly in these complex block copolymer systems, a red fluorescent protein was expressed in E. coli and site-specifically conjugated to a low polydispersity poly(N-isopropyl acrylamide) (PNIPAM) block using thiol-maleimide coupling to form a well-defined model globular protein-polymer diblock. Functional protein materials are obtained by solvent evaporation and solvent annealing above and below the lower critical solution temperature of PNIPAM in order to access different pathways toward self-assembly. Small angle x-ray scattering and microscopy are used to show that the diblock forms lamellar nanostructures and to explore dependence of nanostructure formation on processing conditions. Circular dichroism and UV-vis show that a large fraction of the protein remains in its folded state after conjugation, and wide angle x-ray scattering demonstrates that diblock copolymer self-assembly changes the protein packing symmetry.

Thomas, C. S.; Olsen, B. D.

2011-03-01

353

The dynamin middle domain is critical for tetramerization and higher-order self-assembly  

PubMed Central

The large multidomain GTPase dynamin self-assembles around the necks of deeply invaginated coated pits at the plasma membrane and catalyzes vesicle scission by mechanisms that are not yet completely understood. Although a structural role for the ‘middle' domain in dynamin function has been suggested, it has not been experimentally established. Furthermore, it is not clear whether this putative function pertains to dynamin structure in the unassembled state or to its higher-order self-assembly or both. Here, we demonstrate that two mutations in this domain, R361S and R399A, disrupt the tetrameric structure of dynamin in the unassembled state and impair its ability to stably bind to and nucleate higher-order self-assembly on membranes. Consequently, these mutations also impair dynamin's assembly-dependent stimulated GTPase activity. PMID:17170701

Ramachandran, Rajesh; Surka, Mark; Chappie, Joshua S; Fowler, Douglas M; Foss, Ted R; Song, Byeong Doo; Schmid, Sandra L

2007-01-01

354

Thermal and structural stability of medium energy target carrier assembly for NOvA at Fermilab  

SciTech Connect

The NOvA project will upgrade the existing Neutrino at Main Injector (NuMI) project beamline at Fermilab to accommodate beam power of 700 kW. The Medium Energy (ME) graphite target assembly is provided through an accord with the State Research Center of Russia Institute for High Energy Physics (IHEP) at Protvino, Russia. The effects of proton beam energy deposition within beamline components are considered as thermal stability of the target carrier assembly and alignment budget are critical operational issues. Results of finite element thermal and structural analysis involving the target carrier assembly is provided with detail regarding the target's beryllium windows.

McGee, M.W.; Ader, C.; Anderson, K.; Hylen, J.; Martens, M.; /Fermilab

2010-05-01

355

Acceleration of Amide Bond Rotation by Encapsulation in the Hydrophobic Interior of a Water-Soluble Supramolecular Assembly  

SciTech Connect

The hydrophobic interior cavity of a self-assembled supramolecular assembly exploits the hydrophobic effect for the encapsulation of tertiary amides. Variable temperature 1H NMR experiments reveal that the free energy barrier for rotation around the C-N amide bond is lowered by up to 3.6 kcal/mol upon encapsulation. The hydrophobic cavity of the assembly is able to stabilize the less polar transition state of the amide rotation process. Carbon-13 labeling studies showed that the {sup 13}C NMR carbonyl resonance increases with temperature for the encapsulated amides which suggests that the assembly is able to favor a twisted for of the amide.

Pluth, Michael D.; Bergman, Robert G.; Raymond, Kenneth N.

2008-04-08

356

The BAGEL assembler generation library  

NASA Astrophysics Data System (ADS)

This paper presents two coupled software packages which receive widespread use in the field of numerical simulations of Quantum Chromo-Dynamics. These consist of the BAGEL library and the BAGEL fermion sparse-matrix library, BFM. The Bagel library can generate assembly code for a number of architectures and is configurable - supporting several precision and memory pattern options to allow architecture specific optimisation. It provides high performance on the QCDOC, BlueGene/L and BlueGene/P parallel computer architectures that are popular in the field of lattice QCD. The code includes a complete conjugate gradient implementation for the Wilson and domain wall fermion actions, making it easy to use for third party codes including the Jefferson Laboratory's CHROMA, UKQCD's UKhadron, and the Riken-Brookhaven-Columbia Collaboration's CPS packages. Program summaryProgram title: Bagel Catalogue identifier: AEFE_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEFE_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: GNU Public License V2 No. of lines in distributed program, including test data, etc.: 109 576 No. of bytes in distributed program, including test data, etc.: 892 841 Distribution format: tar.gz Programming language: C++, assembler Computer: Massively parallel message passing. BlueGene/QCDOC/others. Operating system: POSIX, Linux and compatible. Has the code been vectorised or parallelized?: Yes. 16 384 processors used. Classification: 11.5 External routines: QMP, QDP++ Nature of problem: Quantum Chromo-Dynamics sparse matrix inversion for Wilson and domain wall fermion formulations. Solution method: Optimised Krylov linear solver. Unusual features: Domain specific compiler generates optimised assembly code. Running time: 1 h per matrix inversion; multi-year simulations.

Boyle, Peter A.

2009-12-01

357

Method of monolithic module assembly  

DOEpatents

Methods for "monolithic module assembly" which translate many of the advantages of monolithic module construction of thin-film PV modules to wafered c-Si PV modules. Methods employ using back-contact solar cells positioned atop electrically conductive circuit elements affixed to a planar support so that a circuit capable of generating electric power is created. The modules are encapsulated using encapsulant materials such as EVA which are commonly used in photovoltaic module manufacture. The methods of the invention allow multiple cells to be electrically connected in a single encapsulation step rather than by sequential soldering which characterizes the currently used commercial practices.

Gee, James M. (Albuquerque, NM); Garrett, Stephen E. (Albuquerque, NM); Morgan, William P. (Albuquerque, NM); Worobey, Walter (Albuquerque, NM)

1999-01-01

358

Switchable supramolecular assemblies on graphene  

NASA Astrophysics Data System (ADS)

We studied the self-assembly of trimesic acid on single- and few-layer graphene supported by SiO2 substrates. A scanning tunneling microscope operated under ambient conditions was utilized to image supramolecular networks of trimesic acid at liquid-graphene interfaces. Trimesic acid can self-assemble into large-scale, highly ordered adlayers on graphene surfaces. Phase transition of the trimesic acid adlayer from a close-packed structure to a porous chicken-wire structure was observed by changing from single- to few-layer graphene, which was attributed to the modulation of molecule-graphene interactions by the layer number of graphene. The guest-induced phase transition of trimesic acid by complexation with coronene on single-layer graphene further confirms that supramolecular networks on graphene can be rationally tailored with sub-nanometer resolution by balancing between intermolecular vs. molecule-graphene interactions. We further investigated the effects of trimesic acid adlayers on the electronic transport properties of graphene transistors. The adsorption of trimesic acid induces p-doping and defects in the adlayers cause scattering of charge carriers in single-layer graphene.We studied the self-assembly of trimesic acid on single- and few-layer graphene supported by SiO2 substrates. A scanning tunneling microscope operated under ambient conditions was utilized to image supramolecular networks of trimesic acid at liquid-graphene interfaces. Trimesic acid can self-assemble into large-scale, highly ordered adlayers on graphene surfaces. Phase transition of the trimesic acid adlayer from a close-packed structure to a porous chicken-wire structure was observed by changing from single- to few-layer graphene, which was attributed to the modulation of molecule-graphene interactions by the layer number of graphene. The guest-induced phase transition of trimesic acid by complexation with coronene on single-layer graphene further confirms that supramolecular networks on graphene can be rationally tailored with sub-nanometer resolution by balancing between intermolecular vs. molecule-graphene interactions. We further investigated the effects of trimesic acid adlayers on the electronic transport properties of graphene transistors. The adsorption of trimesic acid induces p-doping and defects in the adlayers cause scattering of charge carriers in single-layer graphene. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr01796j

Zhou, Qiaoyu; Li, Yibao; Li, Qiang; Wang, Yibing; Yang, Yanlian; Fang, Ying; Wang, Chen

2014-06-01

359

Parallel Assembly of LIGA Components  

SciTech Connect

In this paper, a prototype robotic workcell for the parallel assembly of LIGA components is described. A Cartesian robot is used to press 386 and 485 micron diameter pins into a LIGA substrate and then place a 3-inch diameter wafer with LIGA gears onto the pins. Upward and downward looking microscopes are used to locate holes in the LIGA substrate, pins to be pressed in the holes, and gears to be placed on the pins. This vision system can locate parts within 3 microns, while the Cartesian manipulator can place the parts within 0.4 microns.

Christenson, T.R.; Feddema, J.T.

1999-03-04

360

Histone acetylation in heterochromatin assembly  

PubMed Central

Histone acetylation is generally considered a mark involved in activating gene expression by making chromatin structures less compact. In the April 1, 2010, issue of Genes & Development, Xhemalce and Kouzarides (pp. 647–652) demonstrate that the acetylation of histone H3 at Lys 4 (H3K4) plays a role in the formation of repressive heterochromatin in Schizosaccharomyces pombe. H3K4 acetylation mediates a switch of chromodomain proteins associated with methylated H3K9 during heterochromatin assembly. PMID:20395362

Kim, Jeong-Hoon; Workman, Jerry L.

2010-01-01

361

Automated Array Assembly, Phase 2  

NASA Technical Reports Server (NTRS)

The Automated Array Assembly Task, Phase 2 of the Low Cost Silicon Solar Array Project is a process development task. The contract provides for the fabrication of modules from large area tandem junction cells (TJC). During this quarter, effort was focused on the design of a large area, approximately 36 sq cm, TJC and process verification runs. The large area TJC design was optimized for minimum I squared R power losses. In the TJM activity, the cell-module interfaces were defined, module substrates were formed and heat treated and clad metal interconnect strips were fabricated.

Carbajal, B. G.

1979-01-01

362

FISHERY STATISTICS UNITED STATES  

E-print Network

FISHERY STATISTICS OF THE UNITED STATES 1973 STATISTICAL DIGEST NO. 67 Prepared by STATISTICS a review of the fishery statistics for the year 1973 . These statistics include data on the volume in assembling data on the fisheries. In certain areas, information complete enough to be used by the statistical

363

Microtubule assembly in meiotic extract requires glycogen  

PubMed Central

The assembly of microtubules during mitosis requires many identified components, such as ?-tubulin ring complex (?-TuRC), components of the Ran pathway (e.g., TPX2, HuRP, and Rae1), and XMAP215/chTOG. However, it is far from clear how these factors function together or whether more factors exist. In this study, we used biochemistry to attempt to identify active microtubule nucleation protein complexes from Xenopus meiotic egg extracts. Unexpectedly, we found both microtubule assembly and bipolar spindle assembly required glycogen, which acted both as a crowding agent and as metabolic source glucose. By also reconstituting microtubule assembly in clarified extracts, we showed microtubule assembly does not require ribosomes, mitochondria, or membranes. Our clarified extracts will provide a powerful tool for activity-based biochemical fractionations for microtubule assembly. PMID:21737678

Groen, Aaron C.; Coughlin, Margaret; Mitchison, Timothy J.

2011-01-01

364

Pathways for virus assembly around nucleic acids  

E-print Network

Understanding the pathways by which viral capsid proteins assemble around their genomes could identify key intermediates as potential drug targets. In this work we use computer simulations to characterize assembly over a wide range of capsid protein-protein interaction strengths and solution ionic strengths. We find that assembly pathways can be categorized into two classes, in which intermediates are either predominantly ordered or disordered. Our results suggest that estimating the protein-protein and the protein-genome binding affinities may be sufficient to predict which pathway occurs. Furthermore, the calculated phase diagrams suggest that knowledge of the dominant assembly pathway and its relationship to control parameters could identify optimal strategies to thwart or redirect assembly to block infection. Finally, analysis of simulation trajectories suggests that the two classes of assembly pathways can be distinguished in single molecule fluorescence correlation spectroscopy or bulk time resolved sma...

Perlmutter, Jason D; Hagan, Michael F

2014-01-01

365

Pathways for virus assembly around nucleic acids  

E-print Network

Understanding the pathways by which viral capsid proteins assemble around their genomes could identify key intermediates as potential drug targets. In this work we use computer simulations to characterize assembly over a wide range of capsid protein-protein interaction strengths and solution ionic strengths. We find that assembly pathways can be categorized into two classes, in which intermediates are either predominantly ordered or disordered. Our results suggest that estimating the protein-protein and the protein-genome binding affinities may be sufficient to predict which pathway occurs. Furthermore, the calculated phase diagrams suggest that knowledge of the dominant assembly pathway and its relationship to control parameters could identify optimal strategies to thwart or redirect assembly to block infection. Finally, analysis of simulation trajectories suggests that the two classes of assembly pathways can be distinguished in single molecule fluorescence correlation spectroscopy or bulk time resolved small angle x-ray scattering experiments.

Jason D Perlmutter; Matthew R Perkett; Michael F Hagan

2014-05-13

366

Archimedes : An experiment in automating mechanical assembly  

SciTech Connect

Archimedes is a prototype mechanical assembly system which generates and executes robot assembly programs from a CAD model input. The system addresses the unrealized potential for flexibility in robotic mechanical assembly applications by automating the programming task. Input is a solid model of the finished assembly. Using this model. Archimedes deduces geometric assembly constraints and then produces an assembly plan that satisfies the geometric constraints, as well as other constraints such as stability and accessibility. A retargetable plan compiler converts the generic plan into robot and cell specific code, including recognition routines for a vision system. In the prototype system the code is executed in a workcell containing an Adept Two robot, a vision system, and other parts handling equipment. 8 refs., 2 figs.

Strip, D. (Sandia National Labs., Albuquerque, NM (USA)); Maciejewski, A.A. (Purdue Univ., Lafayette, IN (USA). Dept. of Electrical Engineering)

1990-01-01

367

The MARVEL assembly for neutron multiplication  

SciTech Connect

A new multiplying test assembly is under development at Idaho National Laboratory to support research, validation, evaluation, and learning. The item is comprised of three stacked, highly-enriched uranium (HEU) cylinders, each 11.4 cm in diameter and having a combined height of up to 11.7 cm. The combined mass of all three cylinders is 20.3 kg of HEU. Calculations for the bare configuration of the assembly indicate a multiplication level of >3.5 (keff=0.72). Reflected configurations of the assembly, using either polyethylene or tungsten, are possible and have the capability of raising the assembly's multiplication level to greater than 10. This paper describes simulations performed to assess the assembly's multiplication level under different conditions and describes the resources available at INL to support the use of these materials. We also describe some preliminary calculations and test activities using the assembly to study neutron multiplication.

David L. Chichester; Mathew T. Kinlaw

2013-10-01

368

Visual Circuit Assembly in Drosophila  

PubMed Central

Both insect and vertebrate visual circuits are organized into orderly arrays of columnar and layered synaptic units that correspond to the array of photoreceptors in the eye. Recent genetic studies in Drosophila have yielded insights into the molecular and cellular mechanisms that pattern the layers and columns and establish specific connections within the synaptic units. A sequence of inductive events and complex cellular interactions coordinates the assembly of visual circuits. Photoreceptor-derived ligands, such as hedgehog and Jelly-Belly, induce target development and expression of specific adhesion molecules, which in turn serve as guidance cues for photoreceptor axons. Afferents are directed to specific layers by adhesive afferent-target interactions mediated by leucine-rich repeat proteins and cadherins, which are restricted spatially and/or modulated dynamically. Afferents are restricted to their topographically appropriate columns by repulsive interactions between afferents and by autocrine Activin signalling. Finally, Dscam-mediated repulsive interactions between target neuron dendrites ensure appropriate combinations of post-synaptic elements at synapses. Essentially all of these Drosophila molecules have vertebrate homologs, some of which are known to carry out analogous functions. Thus, the studies of Drosophila visual circuit development would shed light on neural circuit assembly in general. PMID:21538922

Melnattur, Krishna V.; Lee, Chi-Hon

2014-01-01

369

Planetary Assembly in Binary Systems  

NASA Astrophysics Data System (ADS)

The existence of planets born in environments highly perturbed by a stellar companion represents a major challenge to the paradigm of planet formation. In numerical simulations, the presence of a close binary companion stirs up the relative velocity between planetesimals, which is fundamental in determining the balance between accretion and erosion. Aerodynamic drag from a putative protoplanetary disk exhacerbates the issue by differentially phasing planetesimal orbits in a size-dependent fashion, ultimately interfering or halting altogether the delicate phase of assembly of planetary embryos in large regions of the protoplanetary disk. However, the detection of several planets in tight binary systems and the recent discovery of circumbinary planets (Kepler 16-b, 34-b, and 35-b) establishes that planet formation in binary systems is clearly viable. We perform N-body and hydrodynamical simulations of planetesimals embedded in a protoplanetary disk, subject to the gravitational perturbation of a stellar companion, and follow the collision history among planetesimals. We identify a number of physical processes (including the hitherto unexplored complication of small-scale turbulence in the disk) that conspire to make the binary environment particularly hostile to planetary assembly.

Meschiari, Stefano

2012-10-01

370

Demisable Reaction-Wheel Assembly  

NASA Technical Reports Server (NTRS)

A document discusses the concept of a demisable motor-drive-and-flywheel assembly [reaction-wheel assembly (RWA)] used in controlling the attitude of a spacecraft. Demisable as used here does not have its traditional legal meaning; instead, it signifies susceptible to melting, vaporizing, and/or otherwise disintegrating during re-entry of the spacecraft into the atmosphere of the Earth so as not to pose a hazard to anyone or anything on the ground. Prior RWAs include parts made of metals (e.g., iron, steel, and titanium) that melt at high temperatures and include structures of generally closed character that shield some parts (e.g., magnets) against re-entry heating. In a demisable RWA, the flywheel would be made of aluminum, which melts at a lower temperature. The flywheel web would not be a solid disk but would have a more open, nearly-spoke-like structure so that it would disintegrate more rapidly; hence, the flywheel rim would separate more rapidly so that parts shielded by the rim would be exposed sooner to re-entry heating. In addition, clearances between the flywheel and other components would be made greater, imparting a more open character and thus increasing the exposure of those components.

Roder, Russell; Ahronovich, Eliezer; Davis, Milton C., III

2008-01-01

371

The Michoud Assembly Facility (MAF)  

NASA Technical Reports Server (NTRS)

NASA's Michoud Assembly Facility, located in eastern New Orleans, Louisiana, is an 832 acre site that is a government-owned, contractor-operated component of the George C. Marshall Space Flight Center (MSFC). The facility was acquired by NASA in 1961 at the recommendation of Dr. Wernher von Braun and his rocket team in Huntsville Alabama. The cavernous plant served as the assembly facility for the Saturn launch vehicles and most recently the external tank (ET) used for the Space Shuttle Program. The facility features one of the world's biggest manufacturing plants with 43 acres under one roof and a port with deep-water access for the transportation of large space structures. When completed, space hardware is towed on a barge across the Gulf of Mexico, around Florida and up to Kennedy Space Center. The original tract of land was part of a 34,500 acre French Royal land grant to local merchant, Gilbert Antoine de St. Maxent in 1763. Later, the land was acquired by French transplant Antoine Michoud, the son of Napoleon's Administrator of Domains, who moved to the city in 1827. Michoud operated a sugar cane plantation and refinery on the site until his death in 1863. His heirs continued operating the refinery and kept the original St. Maxent estate intact into the 20th century. Two brick smokestacks from the original refinery still stand before the Michoud facility today.

2000-01-01

372

The Michoud Assembly Facility (MAF)  

NASA Technical Reports Server (NTRS)

NASA's Michoud Assembly Facility, located in eastern New Orleans, Louisiana, is an 832 acre site that is a government-owned, contractor-operated component of the George C. Marshall Space Flight Center (MSFC). The facility was acquired by NASA in 1961 at the recommendation of Dr. Wernher von Braun and his rocket team in Huntsville Alabama. The cavernous plant served as the assembly facility for the Saturn launch vehicles and most recently the external tank (ET) used for the Space Shuttle Program. The facility features one of the world's biggest manufacturing plants with 43 acres under one roof and a port with deep-water access for the transportation of large space structures. When completed, space hardware is towed on a barge across the Gulf of Mexico, around Florida and up to Kennedy Space Center. The original tract of land was part of a 34,500 acre French Royal land grant to local merchant, Gilbert Antoine de St. Maxent in 1763. Later, the land was acquired by French transplant Antoine Michoud, the son of Napoleon's Administrator of Domains, who moved to the city in 1827. Michoud operated a sugar cane plantation and refinery on the site until his death in 1863. His heirs continued operating the refinery and kept the original St. Maxent estate intact into the 20th century. Visible on the right, is one of two brick smokestacks from the original refinery that still stand before the Michoud facility today.

2000-01-01

373

Switchable supramolecular assemblies on graphene.  

PubMed

We studied the self-assembly of trimesic acid on single- and few-layer graphene supported by SiO2 substrates. A scanning tunneling microscope operated under ambient conditions was utilized to image supramolecular networks of trimesic acid at liquid-graphene interfaces. Trimesic acid can self-assemble into large-scale, highly ordered adlayers on graphene surfaces. Phase transition of the trimesic acid adlayer from a close-packed structure to a porous chicken-wire structure was observed by changing from single- to few-layer graphene, which was attributed to the modulation of molecule-graphene interactions by the layer number of graphene. The guest-induced phase transition of trimesic acid by complexation with coronene on single-layer graphene further confirms that supramolecular networks on graphene can be rationally tailored with sub-nanometer resolution by balancing between intermolecular vs. molecule-graphene interactions. We further investigated the effects of trimesic acid adlayers on the electronic transport properties of graphene transistors. The adsorption of trimesic acid induces p-doping and defects in the adlayers cause scattering of charge carriers in single-layer graphene. PMID:24942365

Zhou, Qiaoyu; Li, Yibao; Li, Qiang; Wang, Yibing; Yang, Yanlian; Fang, Ying; Wang, Chen

2014-07-21

374

Algorithms for automated DNA assembly  

PubMed Central

Generating a defined set of genetic constructs within a large combinatorial space provides a powerful method for engineering novel biological functions. However, the process of assembling more than a few specific DNA sequences can be costly, time consuming and error prone. Even if a correct theoretical construction scheme is developed manually, it is likely to be suboptimal by any number of cost metrics. Modular, robust and formal approaches are needed for exploring these vast design spaces. By automating the design of DNA fabrication schemes using computational algorithms, we can eliminate human error while reducing redundant operations, thus minimizing the time and cost required for conducting biological engineering experiments. Here, we provide algorithms that optimize the simultaneous assembly of a collection of related DNA sequences. We compare our algorithms to an exhaustive search on a small synthetic dataset and our results show that our algorithms can quickly find an optimal solution. Comparison with random search approaches on two real-world datasets show that our algorithms can also quickly find lower-cost solutions for large datasets. PMID:20335162

Densmore, Douglas; Hsiau, Timothy H.-C.; Kittleson, Joshua T.; DeLoache, Will; Batten, Christopher; Anderson, J. Christopher

2010-01-01

375

Subsea production test valve assembly  

SciTech Connect

In the subsea test assembly securable within a blowout preventer stack above a subterranean well and positionable between upper and lower portions of a tubular conduit in fluid communication with a production zone within the well, the test assembly is described including an upper subassembly carriable with the upper conduit portion, a lower subassembly carriable with the lower conduit portion, and valve means in the lower subassembly manipulatable between opened and closed positions to control fluid flow within the conduit. The improvement comprises: the upper subassembly including an upper housing and first rigid dog means fixedly secured to the upper housing; the lower subassembly including a lower housing and second rigid dog means fixedly secured to the lower housing; the first rigid dog means positionable between a latch position for latching the upper and lower subassemblies and an unlatch position for unlatching the upper and lower subassemblies upon rotational movement of the first dog means with respect to the second dog means; and lock means axially movable relative to the first and second dog means from a lock position for limiting rotational movement of the first dog means with respect to the second dog means to an unlock position for allowing the first dog means to rotate relative to the second dog means and unlatch the upper subassembly from the lower subassembly.

Yates, P.D.

1988-03-22

376

Plasma Pyrolysis Assembly Regeneration Evaluation  

NASA Technical Reports Server (NTRS)

In April 2010 the Carbon Dioxide Reduction Assembly (CRA) was delivered to the International Space Station (ISS). This technology requires hydrogen to recover oxygen from carbon dioxide. This results in the production of water and methane. Water is electrolyzed to provide oxygen to the crew. Methane is vented to space resulting in a loss of valuable hydrogen and unreduced carbon dioxide. This is not critical for ISS because of the water resupply from Earth. However, in order to have enough oxygen for long-term missions, it will be necessary to recover the hydrogen to maximize oxygen recovery. Thus, the Plasma Pyrolysis Assembly (PPA) was designed to recover hydrogen from methane. During operation, the PPA produces small amounts of carbon that can ultimately reduce performance by forming on the walls and windows of the reactor chamber. The carbon must be removed, although mechanical methods are highly inefficient, thus chemical methods are of greater interest. The purpose of this effort was to determine the feasibility of chemically removing the carbon from the walls and windows of a PPA reactor using a pure carbon dioxide stream.

Medlen, Amber; Abney, Morgan B.; Miller, Lee A.

2011-01-01

377

Rigidity analysis of protein biological assemblies and periodic crystal structures  

PubMed Central

Background We initiate in silico rigidity-theoretical studies of biological assemblies and small crystals for protein structures. The goal is to determine if, and how, the interactions among neighboring cells and subchains affect the flexibility of a molecule in its crystallized state. We use experimental X-ray crystallography data from the Protein Data Bank (PDB). The analysis relies on an effcient graph-based algorithm. Computational experiments were performed using new protein rigidity analysis tools available in the new release of our KINARI-Web server http://kinari.cs.umass.edu. Results We provide two types of results: on biological assemblies and on crystals. We found that when only isolated subchains are considered, structural and functional information may be missed. Indeed, the rigidity of biological assemblies is sometimes dependent on the count and placement of hydrogen bonds and other interactions among the individual subchains of the biological unit. Similarly, the rigidity of small crystals may be affected by the interactions between atoms belonging to different unit cells. We have analyzed a dataset of approximately 300 proteins, from which we generated 982 crystals (some of which are biological assemblies). We identified two types of behaviors. (a) Some crystals and/or biological assemblies will aggregate into rigid bodies that span multiple unit cells/asymmetric units. Some of them create substantially larger rigid cluster in the crystal/biological assembly form, while in other cases, the aggregation has a smaller effect just at the interface between the units. (b) In other cases, the rigidity properties of the asymmetric units are retained, because the rigid bodies did not combine. We also identified two interesting cases where rigidity analysis may be correlated with the functional behavior of the protein. This type of information, identified here for the first time, depends critically on the ability to create crystals and biological assemblies, and would not have been observed only from the asymmetric unit. For the Ribonuclease A protein (PDB file 5RSA), which is functionally active in the crystallized form, we found that the individual protein and its crystal form retain the flexibility parameters between the two states. In contrast, a derivative of Ribonuclease A (PDB file 9RSA), has no functional activity, and the protein in both the asymmetric and crystalline forms, is very rigid. For the vaccinia virus D13 scaffolding protein (PDB file 3SAQ), which has two biological assemblies, we observed a striking asymmetry in the rigidity cluster decomposition of one of them, which seems implausible, given its symmetry. Upon careful investigation, we tracked the cause to a placement decision by the Reduce software concerning the hydrogen atoms, thus affecting the distribution of certain hydrogen bonds. The surprising result is that the presence or lack of a very few, but critical, hydrogen bonds, can drastically affect the rigid cluster decomposition of the biological assembly. Conclusion The rigidity analysis of a single asymmetric unit may not accurately reflect the protein's behavior in the tightly packed crystal environment. Using our KINARI software, we demonstrated that additional functional and rigidity information can be gained by analyzing a protein's biological assembly and/or crystal structure. However, performing a larger scale study would be computationally expensive (due to the size of the molecules involved). Overcoming this limitation will require novel mathematical and computational extensions to our software. PMID:24564201

2013-01-01

378

From system F to typed assembly language  

Microsoft Academic Search

We motivate the design of typed assembly language (TAL) and present a type-preserving ttranslation from Systemn F to TAL. The typed assembly language we pressent is based on a conventional RISC assembly language, but its static type sytem provides support for enforcing high-level language abstratctions, such as closures, tuples, and user-defined abstract data types. The type system ensures that well-typed

Greg Morrisett; David Walker; Karl Crary; Neal Glew

1999-01-01

379

Assembly of eukaryotic algal chromosomes in yeast  

PubMed Central

Background Synthetic genomic approaches offer unique opportunities to use powerful yeast and Escherichia coli genetic systems to assemble and modify chromosome-sized molecules before returning the modified DNA to the target host. For example, the entire 1 Mb Mycoplasma mycoides chromosome can be stably maintained and manipulated in yeast before being transplanted back into recipient cells. We have previously demonstrated that cloning in yeast of large (>?~?150 kb), high G?+?C (55%) prokaryotic DNA fragments was improved by addition of yeast replication origins every ~100 kb. Conversely, low G?+?C DNA is stable (up to at least 1.8 Mb) without adding supplemental yeast origins. It has not been previously tested whether addition of yeast replication origins similarly improves the yeast-based cloning of large (>150 kb) eukaryotic DNA with moderate G?+?C content. The model diatom Phaeodactylum tricornutum has an average G?+?C content of 48% and a 27.4 Mb genome sequence that has been assembled into chromosome-sized scaffolds making it an ideal test case for assembly and maintenance of eukaryotic chromosomes in yeast. Results We present a modified chromosome assembly technique in which eukaryotic chromosomes as large as ~500 kb can be assembled from cloned ~100 kb fragments. We used this technique to clone fragments spanning P. tricornutum chromosomes 25 and 26 and to assemble these fragments into single, chromosome-sized molecules. We found that addition of yeast replication origins improved the cloning, assembly, and maintenance of the large chromosomes in yeast. Furthermore, purification of the fragments to be assembled by electroelution greatly increased assembly efficiency. Conclusions Entire eukaryotic chromosomes can be successfully cloned, maintained, and manipulated in yeast. These results highlight the improvement in assembly and maintenance afforded by including yeast replication origins in eukaryotic DNA with moderate G?+?C content (48%). They also highlight the increased efficiency of assembly that can be achieved by purifying fragments before assembly. PMID:24325901

2013-01-01

380

Algorithm for a Microfluidic Assembly Line  

NASA Astrophysics Data System (ADS)

Microfluidic technology has revolutionized the control of flows at small scales giving rise to new possibilities for assembling complex structures on the microscale. We analyze different possible algorithms for assembling arbitrary structures, and demonstrate that a sequential assembly algorithm can manufacture arbitrary 3D structures from identical constituents. We illustrate the algorithm by showing that a modified Hele-Shaw cell with 7 controlled flow rates can be designed to construct the entire English alphabet from particles that irreversibly stick to each other.

Schneider, Tobias M.; Mandre, Shreyas; Brenner, Michael P.

2011-03-01

381

Assembling ( = 0) .word 0xABC  

E-print Network

Assembling ( = 0) lis $3 .word 0xABC lis $1 .word A jr $1 B: jr $31 A: beq $0, $0, B .word B asm 1 #12;Assembling ( = 0) lis $3 .word 0xABC lis $1 .word A jr $1 B: jr $31 A: beq $0, $0, B .word B;Assembling/Loading ( = 0) · We can't always load our programs starting at memory address = 0 · When > 0 we

Waterloo, University of

382

A Versatile Computer-Controlled Assembly System  

Microsoft Academic Search

Abstract A versatile assembly system, using TV cameras and oomputer-controlled arm and moving table, is described. It makes almple,assemblies,such aa a peg and rings and a toy car. It separates parts from a heap, recognising them with an overhead camera, then assembles them by feel.,It can be instructed,to perform a new task with different,parte by spending,an hour showing,it the parts

A. P. Ambler; Harry G. Barrow; Christopher M. Brown; Rod M. Burstall; Robin J. Popplestone

1973-01-01

383

Report of the Assembly Subcommittee on Indian Affairs to the Standing Committee on Governmental Operations.  

ERIC Educational Resources Information Center

The 1970 legislative session of the New York State Assembly created the Subcommittee on Indian Affairs to review New York's Indian Law and state services provided to Indian reservations. Seven hearings were held on reservations to gather opinions, suggestions, and criticisms of the on-reservation Indian community. In addition, a special hearing…

New York State Assembly, Albany.

384

Fabrication of capsule assemblies, phase 3  

NASA Technical Reports Server (NTRS)

Thirteen capsule assemblies were fabricated for evaluation of fuel pin design concepts for a fast spectrum lithium cooled compact space power reactor. These instrumented assemblies were designed for real time test of prototype fuel pins. Uranium mononitride fuel pins were encased in AISI 304L stainless steel capsules. Fabrication procedures were fully qualified by process development and assembly qualification tests. Instrumentation reliability was achieved utilizing specially processed and closely controlled thermocouple hot zone fabrication and by thermal screening tests. Overall capsule reliability was achieved with an all electron beam welded assembly.

Keeton, A. R.; Stemann, L. G.

1973-01-01

385

Selective assembly in deformable systems using templated assembly by selective removal  

E-print Network

The current work presents the first demonstration of successful assembly of deformable polymer microspheres on patterned rigid substrates using Templated Assembly by Selective Removal (TASR). Also presented is a quantitative ...

Agarwal, Gunjan

2009-01-01

386

Assembly and post-assembly manipulation of polyelectrolyte multilayers for control of bacterial attachment and viability  

E-print Network

The overall goal of this thesis was to exploit the versatility of the polyelectrolyte multilayer (PEM) platform to consider bacteria-substrata interactions by varying multilayer assembly and post-assembly conditions. We ...

Lichter, Jenny, 1982-

2009-01-01

387

Motor Drive Electronics Assembly for Mars Curiosity Rover: An Example of Assembly Qualification for Extreme Environments.  

National Technical Information Service (NTIS)

This paper describes the technology development and infusion of a motor drive electronics assembly for Mars Curiosity Rover under space extreme environments. The technology evaluation and qualification as well as space qualification of the assembly are de...

C. T. Weber, D. J. Hunter, E. Kolawa, M. M. Mojarradi, Y. Chen

2013-01-01

388

State Environmental Resource Center  

NSDL National Science Digital Library

This website provides information on Wisconsin environmental policies and assembles information and tools to help legislators make decisions on environmental issues. The State Environmental Resource Center identifies effective state policies as well as exposing anti-environmental legislative trends. Included in this site are sample bills, press clips, fact sheets, research, and other background information on a large assortment of environmental issues such as clean energy, urban issues, saving wildlands, safe air and water, children's health, land and water use, and environmental citizenship.

Wildlife, Defenders O.; The State Environmental Resource Center (SERC)

389

Multistep kinetic self-assembly of DNA-coated colloids.  

PubMed

Equilibrium self-assembly relies on the relaxation of disordered mixtures of building blocks towards an ordered ground state. The main drawback of this traditional approach lies in the kinetic traps that often interrupt the progression of the system towards equilibrium and lead to the formation of arrested phases. The latest techniques to control colloidal interactions open up the possibility of exploiting the tendency to dynamically arrest in order to construct amorphous materials with a specific morphology and local separation between multiple components. Here we propose strategies to direct the gelation of two-component colloidal mixtures by sequentially activating selective interactions. We investigate morphological changes in the structure of the arrested phases both by means of molecular dynamics simulations and experimentally by using DNA-coated colloids. Our approach can be exploited to assemble multicomponent mesoporous materials with possible applications in hybrid photovoltaics, photonics and drug delivery. PMID:23759922

Di Michele, Lorenzo; Varrato, Francesco; Kotar, Jurij; Nathan, Simon H; Foffi, Giuseppe; Eiser, Erika

2013-01-01

390

Formation and maintenance of neuronal assemblies through synaptic plasticity.  

PubMed

The architecture of cortex is flexible, permitting neuronal networks to store recent sensory experiences as specific synaptic connectivity patterns. However, it is unclear how these patterns are maintained in the face of the high spike time variability associated with cortex. Here we demonstrate, using a large-scale cortical network model, that realistic synaptic plasticity rules coupled with homeostatic mechanisms lead to the formation of neuronal assemblies that reflect previously experienced stimuli. Further, reverberation of past evoked states in spontaneous spiking activity stabilizes, rather than erases, this learned architecture. Spontaneous and evoked spiking activity contains a signature of learned assembly structures, leading to testable predictions about the effect of recent sensory experience on spike train statistics. Our work outlines requirements for synaptic plasticity rules capable of modifying spontaneous dynamics and shows that this modification is beneficial for stability of learned network architectures. PMID:25395015

Litwin-Kumar, Ashok; Doiron, Brent

2014-01-01

391

Mariner Venus/Mercury 1973 rocket engine assembly  

NASA Technical Reports Server (NTRS)

The fabrication and test of rocket engine assemblies (REA) for Mariner Venus/Mercury 1973 are reported. The fabrication, assembly and flight acceptance test of seven REA's including the type approval test of one engine and fabrication of one additional kit consisting of detail parts for an engine ready for catalyst loading are presented. The MV/M '73 REA which is a nominal 51 lbs thrust monopropellant engine is described. Under steady state operation the specific impulse is not less than 228 lb-sec at 55 lb and 218.5 lb-sec at 10 lb thrust varying linearly between these limits. The characteristic velocity is not less than 4100 ft/sec at any thrust level.

Snoke, D. R.; Williams, R. S.

1972-01-01

392

MODC2 procedures for assembly of MODCOMP-2 programs using the Sigma 5 assembler  

NASA Technical Reports Server (NTRS)

A set of programs was written to enable the METASYMBOL macro-assembler of the Sigma 5 to assemble programs for an attached MODCOMP-2 minicomputer. This program set is a follow-on to previously developed program sets which facilitated assemblies for the PDP-11 and SDS-930.

Layland, J. W.

1976-01-01

393

Self-assembled granular walkers  

E-print Network

Mechanisms of locomotion in microscopic systems are of great interest not only for technological applications, but also for the sake of understanding, and potentially harnessing, processes far from thermal equilibrium. Down-scaling is a particular challenge, and has led to a number of interesting concepts including thermal ratchet systems and asymmetric swimmers. Here we present a system which is particularly intriguing, as it is self-assembling and uses a robust mechanism which can be implemented in various settings. It consists of small spheres of different size which adhere to each other, and are subject to an oscillating (zero average) external force eld. An inherent nonlinearity in the mutual force network leads to force rectication and hence to locomotion. We present a model that accounts for the observed behaviour and demonstrates the wide applicability and potential scalability of the concept.

Z. S. Khan; A. Steinberger; R. Seemann; and S. Herminghaus

2010-03-08

394

Directed actin assembly and motility.  

PubMed

The actin cytoskeleton is a key component of the cellular architecture. However, understanding actin organization and dynamics in vivo is a complex challenge. Reconstitution of actin structures in vitro, in simplified media, allows one to pinpoint the cellular biochemical components and their molecular interactions underlying the architecture and dynamics of the actin network. Previously, little was known about the extent to which geometrical constraints influence the dynamic ultrastructure of these networks. Therefore, in order to study the balance between biochemical and geometrical control of complex actin organization, we used the innovative methodologies of UV and laser patterning to design a wide repertoire of nucleation geometries from which we assembled branched actin networks. Using these methods, we were able to reconstitute complex actin network organizations, closely related to cellular architecture, to precisely direct and control their 3D connections. This methodology mimics the actin networks encountered in cells and can serve in the fabrication of innovative bioinspired systems. PMID:24630113

Boujemaa-Paterski, Rajaa; Galland, Rémi; Suarez, Cristian; Guérin, Christophe; Théry, Manuel; Blanchoin, Laurent

2014-01-01

395

Miniature MT optical assembly (MMTOA)  

DOEpatents

An optical assembly (10) includes a rigid mount (12) with a recess (26) proximate a first side thereof, a substrate (14), and an optical die (16) flip-chip bonded to the substrate (14). The substrate (14) is secured to the first side of the mount and includes a plurality of die bonding elements (40), a plurality of optical apertures (32), and a plurality of external bonding elements (42). A plurality of traces (44) interconnect the die bonding elements (40) and the external bonding elements (42). The optical die (16) includes a plurality of optical elements, each element including an optical signal interface (48), the die being bonded to the plurality of die bonding elements (40) such that the optical signal interface (48) of each element is in registry with an optical aperture (32) of the substrate (14) and the die (16) is at least partially enclosed by the recess (26).

Laughlin, Daric (Overland Park, KS); Abel, Phillip (Overland Park, KS)

2008-04-01

396

Nanopatterned self-assembled monolayers.  

PubMed

We report on the fabrication of chemically nanopatterned gold surfaces by combining electron-beam lithography with gas and liquid phase thiolization. The line-edge roughness of the patterns is ?4 nm, corresponding to a limiting feature size in the range of 15 nm. Indications for a lower packing density of the self-assembled monolayers grown in the nanofeatures are given, and evidences for the bleeding of thiols along the grain boundaries of the gold substrate are displayed. A comparison is provided between nanopatterned thiol and silane monolayers on gold and on silicon wafers, respectively. The line-edge roughnesses are shown to be close to each other for these two systems, indicating that the limiting step is currently the lithography step, suggesting possible improvement of the resolution. The advantages and drawbacks of thiol versus silane monolayers are finally discussed with respect to the formation of chemically nanopatterned surfaces. PMID:21727398

Baralia, Gabriel G; Pallandre, Antoine; Nysten, Bernard; Jonas, Alain M

2006-02-28

397

Nanopatterned self-assembled monolayers  

NASA Astrophysics Data System (ADS)

We report on the fabrication of chemically nanopatterned gold surfaces by combining electron-beam lithography with gas and liquid phase thiolization. The line-edge roughness of the patterns is ~4 nm, corresponding to a limiting feature size in the range of 15 nm. Indications for a lower packing density of the self-assembled monolayers grown in the nanofeatures are given, and evidences for the bleeding of thiols along the grain boundaries of the gold substrate are displayed. A comparison is provided between nanopatterned thiol and silane monolayers on gold and on silicon wafers, respectively. The line-edge roughnesses are shown to be close to each other for these two systems, indicating that the limiting step is currently the lithography step, suggesting possible improvement of the resolution. The advantages and drawbacks of thiol versus silane monolayers are finally discussed with respect to the formation of chemically nanopatterned surfaces.

Baralia, Gabriel G.; Pallandre, Antoine; Nysten, Bernard; Jonas, Alain M.

2006-02-01

398

Visualization software for molecular assemblies.  

PubMed

Software for viewing three-dimensional models and maps of viruses, ribosomes, filaments, and other molecular assemblies is advancing on many fronts. New developments include molecular representations that offer better control over level of detail, lighting that improves the perception of depth, and two-dimensional projections that simplify data interpretation. Programmable graphics processors offer quality, speed, and visual effects not previously possible, while 3D printers, haptic interaction devices, and auto-stereo displays show promise in more naturally engaging our senses. Visualization methods are developed by diverse groups of researchers with differing goals: experimental biologists, database developers, computer scientists, and package developers. We survey recent developments and problems faced by the developer community in bringing innovative visualization methods into widespread use. PMID:17728125

Goddard, Thomas D; Ferrin, Thomas E

2007-10-01

399

Diverter assembly for radioactive material  

DOEpatents

A diverter assembly for diverting a pneumatically conveyed holder for a radioactive material between a central conveying tube and one of a plurality of radially offset conveying tubes includes an airtight container. A diverter tube having an offset end is suitably mounted in the container for rotation. A rotary seal seals one end of the diverter tube during and after rotation of the diverter tube while a spring biased seal seals the other end of the diverter tube which mvoes between various offset conveying tubes. An indexing device rotatably indexes the diverter tube and this indexing device is driven by a suitable drive. The indexing mechanism is preferably a geneva-type mechanism to provide a locking of the diverter tube in place.

Andrews, Katherine M. (Pittsburgh, PA); Starenchak, Robert W. (Youngwood, PA)

1989-01-01

400

Supracellular actomyosin assemblies during development  

PubMed Central

Changes in cell shape are one of the driving forces of tissue morphogenesis. Contractile cytoskeletal assemblies based on actomyosin networks have emerged as a main player that can drive these changes. Different types of actomyosin networks have been identified, with distinct subcellular localizations, including apical junctional and apicomedial actomyosin. A further specialization of junctional actomyosin are so-called actomyosin ‘cables’, supracellular arrangements that appear to stretch over many cell diameters. Such actomyosin cables have been shown to serve several important functions, in processes such as wound healing, epithelial morphogenesis and maintenance of compartment identities during development. In the Drosophila embryo, we have recently identified a function for a circumferential actomyosin cable in assisting tube formation. Here, I will briefly summarize general principles that have emerged from the analysis of such cables. PMID:23760352

2013-01-01

401

Low inductance power electronics assembly  

DOEpatents

A power electronics assembly is provided. A first support member includes a first plurality of conductors. A first plurality of power switching devices are coupled to the first support member. A first capacitor is coupled to the first support member. A second support member includes a second plurality of conductors. A second plurality of power switching devices are coupled to the second support member. A second capacitor is coupled to the second support member. The first and second pluralities of conductors, the first and second pluralities of power switching devices, and the first and second capacitors are electrically connected such that the first plurality of power switching devices is connected in parallel with the first capacitor and the second capacitor and the second plurality of power switching devices is connected in parallel with the second capacitor and the first capacitor.

Herron, Nicholas Hayden; Mann, Brooks S.; Korich, Mark D.; Chou, Cindy; Tang, David; Carlson, Douglas S.; Barry, Alan L.

2012-10-02

402

Photonic-powered cable assembly  

DOEpatents

A photonic-cable assembly includes a power source cable connector ("PSCC") coupled to a power receive cable connector ("PRCC") via a fiber cable. The PSCC electrically connects to a first electronic device and houses a photonic power source and an optical data transmitter. The fiber cable includes an optical transmit data path coupled to the optical data transmitter, an optical power path coupled to the photonic power source, and an optical feedback path coupled to provide feedback control to the photonic power source. The PRCC electrically connects to a second electronic device and houses an optical data receiver coupled to the optical transmit data path, a feedback controller coupled to the optical feedback path to control the photonic power source, and a photonic power converter coupled to the optical power path to convert photonic energy received over the optical power path to electrical energy to power components of the PRCC.

Sanderson, Stephen N.; Appel, Titus James; Wrye, IV, Walter C.

2013-01-22

403

Modular assembly of optical nanocircuits.  

PubMed

A key element enabling the microelectronic technology advances of the past decades has been the conceptualization of complex circuits with versatile functionalities as being composed of the proper combination of basic 'lumped' circuit elements (for example, inductors and capacitors). In contrast, modern nanophotonic systems are still far from a similar level of sophistication, partially because of the lack of modularization of their response in terms of basic building blocks. Here we demonstrate the design, assembly and characterization of relatively complex photonic nanocircuits by accurately positioning a number of metallic and dielectric nanoparticles acting as modular lumped elements. The nanoparticle clusters produce the desired spectral response described by simple circuit rules and are shown to be dynamically reconfigurable by modifying the direction or polarization of impinging signals. Our work represents an important step towards extending the powerful modular design tools of electronic circuits into nanophotonic systems. PMID:24871450

Shi, Jinwei; Monticone, Francesco; Elias, Sarah; Wu, Yanwen; Ratchford, Daniel; Li, Xiaoqin; Alù, Andrea

2014-01-01

404

Atom-by-atom assembly  

NASA Astrophysics Data System (ADS)

Atomic manipulation using a scanning tunneling microscope (STM) tip enables the construction of quantum structures on an atom-by-atom basis, as well as the investigation of the electronic and dynamical properties of individual atoms on a one-atom-at-a-time basis. An STM is not only an instrument that is used to ‘see’ individual atoms by means of imaging, but is also a tool that is used to ‘touch’ and ‘take’ the atoms, or to ‘hear’ their movements. Therefore, the STM can be considered as the ‘eyes’, ‘hands’ and ‘ears’ of the scientists, connecting our macroscopic world to the exciting atomic world. In this article, various STM atom manipulation schemes and their example applications are described. The future directions of atomic level assembly on surfaces using scanning probe tips are also discussed.

Hla, Saw Wai

2014-05-01

405

Self-assembled artificial cilia  

PubMed Central

Due to their small dimensions, microfluidic devices operate in the low Reynolds number regime. In this case, the hydrodynamics is governed by the viscosity rather than inertia and special elements have to be introduced into the system for mixing and pumping of fluids. Here we report on the realization of an effective pumping device that mimics a ciliated surface and imitates its motion to generate fluid flow. The artificial biomimetic cilia are constructed as long chains of spherical superparamagnetic particles, which self-assemble in an external magnetic field. Magnetic field is also used to actuate the cilia in a simple nonreciprocal manner, resulting in a fluid flow. We prove the concept by measuring the velocity of a cilia-pumped fluid as a function of height above the ciliated surface and investigate the influence of the beating asymmetry on the pumping performance. A numerical simulation was carried out that successfully reproduced the experimentally obtained data. PMID:19934055

Vilfan, Mojca; Poto?nik, Anton; Kav?i?, Blaž; Osterman, Natan; Poberaj, Igor; Vilfan, Andrej; Babi?, Dušan

2010-01-01

406

Snubber assembly for turbine blades  

DOEpatents

A snubber associated with a rotatable turbine blade in a turbine engine, the turbine blade including a pressure sidewall and a suction sidewall opposed from the pressure wall. The snubber assembly includes a first snubber structure associated with the pressure sidewall of the turbine blade, a second snubber structure associated with the suction sidewall of the turbine blade, and a support structure. The support structure extends through the blade and is rigidly coupled at a first end portion thereof to the first snubber structure and at a second end portion thereof to the second snubber structure. Centrifugal loads exerted by the first and second snubber structures caused by rotation thereof during operation of the engine are at least partially transferred to the support structure, such that centrifugal loads exerted on the pressure and suctions sidewalls of the turbine blade by the first and second snubber structures are reduced.

Marra, John J

2013-09-03

407

Passive Optical Sample Assembly (POSA)  

NASA Technical Reports Server (NTRS)

A Passive Optical Sample Assembly (POSA) unit was mounted and flown in the cargo bay of the space shuttle Columbia during the first Orbital Flight Test (OFT-1). A similar unit was mounted in a different location in the cargo bay during the postflight operations. The samples in both POSA arrays were subjected to a series of optical and analytical measurements prior to delivery for installation in the cargo bay and after retrieval of the flight hardware. The final results of a comparison of the two series of measurements are presented. These STS-1 results are based on data obtained from only a portion of one of the ten Induced Environment Contamination Monitor instruments to be flown on several shuttle flights beginning with STS-2. These limited results do not indicate shuttle contamination levels in excess of those anticipated.

Linton, R. C.; Miller, E. R.; Susko, M.

1981-01-01

408

High temperature control rod assembly  

DOEpatents

A high temperature nuclear control rod assembly comprises a plurality of substantially cylindrical segments flexibly joined together in succession by ball joints. The segments are made of a high temperature graphite or carbon-carbon composite. The segment includes a hollow cylindrical sleeve which has an opening for receiving neutron-absorbing material in the form of pellets or compacted rings. The sleeve has a threaded sleeve bore and outer threaded surface. A cylindrical support post has a threaded shaft at one end which is threadably engaged with the sleeve bore to rigidly couple the support post to the sleeve. The other end of the post is formed with a ball portion. A hollow cylindrical collar has an inner threaded surface engageable with the outer threaded surface of the sleeve to rigidly couple the collar to the sleeve. the collar also has a socket portion which cooperates with the ball portion to flexibly connect segments together to form a ball and socket-type joint. In another embodiment, the segment comprises a support member which has a threaded shaft portion and a ball surface portion. The threaded shaft portion is engageable with an inner threaded surface of a ring for rigidly coupling the support member to the ring. The ring in turn has an outer surface at one end which is threadably engageably with a hollow cylindrical sleeve. The other end of the sleeve is formed with a socket portion for engagement with a ball portion of the support member. In yet another embodiment, a secondary rod is slidably inserted in a hollow channel through the center of the segment to provide additional strength. A method for controlling a nuclear reactor utilizing the control rod assembly is also included.

Vollman, Russell E. (Solana Beach, CA)

1991-01-01

409

The effect of zinc on amyloid ?-protein assembly and toxicity: A mechanistic investigation  

NASA Astrophysics Data System (ADS)

Neurotoxic assemblies of amyloid ?-protein (A?) are widely believed to be the cause for Alzheimer's disease (AD). Therefore, understanding the factors and mechanisms that control, modulate, and inhibit formation of these assemblies is crucial for the development of therapeutic intervention of AD. This information also can contribute significantly to our understanding of the mechanisms of other amyloidosis diseases, such as Parkinson's disease, Huntington's disease, type 2 diabetes, amyotrophic lateral sclerosis (Lou Gehrig's disease) and prion diseases (e.g. Mad Cow disease). We have developed a multidisciplinary experimental strategy to study structural and dynamic mechanistic aspects that underlie the A? assembly process. Utilizing this strategy, we explored the molecular basis leading to the perturbation of the A? assembly process by divalent metal ions, mainly Zn2+ ions. Using Zn2+ as reaction physiological relevant probes, it was demonstrated that Zn2+ rapidly (milliseconds) induce self-assembly of A? aggregates and stabilize them in a manner that prevents formation of A? fibrils. Importantly, the early-formed intermediates are substantially more neurotoxic than fibrils. Our results suggest that relevant A? modulators should be targeted against the rapidly evolved intermediate states of A? assembly. The design of such modulators is challenging, as they have to compete with different natural mediators (such as Zn2+) of A? aggregation, which diverse A? assemblies in both specific and nonspecific manners.

Solomonov, Inna; Sagi, Irit

2014-10-01

410

Automatically closing swing gate closure assembly  

DOEpatents

A swing gate closure assembly for nuclear reactor tipoff assembly wherein the swing gate is cammed open by a fuel element or spacer but is reliably closed at a desired closing rate primarily by hydraulic forces in the absence of a fuel charge.

Chang, Shih-Chih (Richland, WA); Schuck, William J. (Richland, WA); Gilmore, Richard F. (Kennewick, WA)

1988-01-01

411

Some Questions about Feature Re-Assembly  

ERIC Educational Resources Information Center

In this commentary, differences between feature re-assembly and feature selection are discussed. Lardiere's proposals are compared to existing approaches to grammatical features in second language (L2) acquisition. Questions are raised about the predictive power of the feature re-assembly approach. (Contains 1 footnote.)

White, Lydia

2009-01-01

412

Program Helps To Optimize Assembly Sequences  

NASA Technical Reports Server (NTRS)

FAST project-management software tool designed to optimize sequence of assembly of Space Station Freedom. Assesses effects of detailed changes upon system and produces output metrics identifying preferred assembly sequences. Incorporates Space-Shuttle integration, Space-Station hardware, on-orbit operations, and governing programmatic considerations as either precedence relations or numerical data. Written in C language.

Borden, Chester S.; Werntz, David G.; Loyola, Steven J.

1992-01-01

413

Broadcast distributed control for assembly modules  

Microsoft Academic Search

Assembly stations, also known as cells, is a generalized term denoting the place where one of the operations is carried out in the sequence needed to assemble a product. As each station m general is dedicated to a specific operation on a specific product, it is uncommon to find two instances of the same station. Stations are custom designed and

I. Lobl

1995-01-01

414

ALSEP CASK ASSEMBLY GEARBOX THERMAL VACUUM TEST  

E-print Network

with the results of a thermal vacuum test on the ACA gearbox assembly which was conducted during the ACA prototype test series. The purpose of the test was to verify the operation of the ACA Gearbox Assembly when. = l. 5 in. 0. 75 in. moment arm. 4. Raw data to true force conversion = 3/. 7 5 = 4 5. Wt of ACA Band

Rathbun, Julie A.

415

Fuel rod assembly to manifold attachment  

DOEpatents

A fuel element is formed with a plurality of fuel rod assemblies detachably connected to an overhead support with each of the fuel rod assemblies having a gas tight seal with the support to allow internal fission gaseous products to flow without leakage from the fuel rod assemblies into a vent manifold passageway system on the support. The upper ends of the fuel rod assemblies are located at vertically extending openings in the support and upper threaded members are threaded to the fuel rod assemblies to connect the latter to the support. The preferred threaded members are cap nuts having a dome wall encircling an upper threaded end on the fuel rod assembly and having an upper sealing surface for sealing contact with the support. Another and lower seal is achieved by abutting a sealing surface on each fuel rod assembly with the support. A deformable portion on the cap nut locks the latter against inadvertent turning off the fuel rod assembly. Orienting means on the fuel rod and support primarily locates the fuel rods azimuthally for reception of a deforming tool for the cap nut. A cross port in the fuel rod end plug discharges into a sealed annulus within the support, which serves as a circumferential chamber, connecting the manifold gas passageways in the support.

Donck, Harry A. (San Diego, CA); Veca, Anthony R. (San Diego, CA); Snyder, Jr., Harold J. (San Diego, CA)

1980-01-01

416

Towards Assembly Automation at Small Size Scales  

E-print Network

for energy storage CardioARM for Cardiac Surgery: Consists of 50 rigid cylindrical links Photo courtesy joints using in-mold assembly · We have characterized the influence of interface geometry. Shroeder, and S. Warth. Manufacturing multi-material articulated plastic products using in-mold assembly

Gupta, Satyandra K.

417

Gene synthesis by circular assembly amplification  

E-print Network

error-containing DNA10. We developed a one-cycle gene synthesis method that substan- tially improvesGene synthesis by circular assembly amplification Duhee Bang & George M Church Here we report the development of a gene-synthesis technology, circular assembly amplification. In this approach, we first

Church, George M.

418

Multilayer Film Assembly of Carbon Nanotubes  

NASA Technical Reports Server (NTRS)

An approach to assemble multilayers of carbon nanotubes on a substrate is presented. Chemical vapor deposition using a transition metal catalyst formulation is used to grow the nanotubes. Results show a bilayer assembly of nanotubes each with a different density of tubes.

Cassell, Alan M.; Meyyappan, M.; Han, Jie; Arnold, J. (Technical Monitor)

2000-01-01

419

Surface Modification with Self-Assembled Monolayer &  

E-print Network

, Absorption - Surface (Gold & Glass (Silicon Wafer), Plastics) of the substrate - Silane (Glass) - Amine (Gold1 1 / 40 Surface Modification with Self-Assembled Monolayer & Polymer Brush for Biotechnology Surface Modification with Self-Assembled Monolayer & Polymer Brush for Biotechnology 2 / 40 linear star

Hong, Deog Ki

420

GPU-Euler: Sequence Assembly Using GPGPU  

Microsoft Academic Search

Advances in sequencing technologies have revolu- tionized the field of genomics by providing cost effective and high throughput solutions. In this paper, we develop a parallel sequence assembler implemented on general purpose graphic processor units (GPUs). Our work was largely motivated by a growing need in the genomic community for sequence assemblers and increasing use of GPUs for general purpose

Syed Faraz Mahmood; Huzefa Rangwala

2011-01-01

421

A network model for plantpollinator community assembly  

E-print Network

. However, models for mutualistic community assembly are still needed, especially because these communities network model that simulates the colonization and extinction pro- cess of mutualistic community assembly, with few free pa- rameters, the dynamics of new mutualistic community formation from the regional source

Albert, Réka

422

Peptide assembly for nanoscale control of materials  

NASA Astrophysics Data System (ADS)

Self-assembly of molecules is an attractive materials construction strategy due to its simplicity in application. By considering peptidic, charged synthetic molecules in the bottom-up materials self-assembly design process, one can take advantage of inherently biomolecular attributes; intramolecular folding events, secondary structure, and electrostatic interactions; in addition to more traditional self-assembling molecular attributes such as amphiphilicty, to define hierarchical material structure and consequent properties. Design strategies for materials self-assembly based on small (less than 24 amino acids) beta-hairpin peptides will be discussed. Self-assembly of the peptides is predicated on an intramolecular folding event caused by desired solution properties. Importantly, kinetics of self-assembly can be tuned in order to control gelation time. The final gel behaves as a shear thinning, but immediately rehealing, solid that is potentially useful for cell injection therapies. The morphological, and viscoelastic properties of these peptide hydrogels will be discussed. In addition, slight changes in peptide primary sequence can have drastic effects on the self-assembled morphology. Additional sequences will be discussed that do not form hydrogels but rather form nanoscale templates for inorganic material assembly.

Pochan, Darrin

2011-03-01

423

Assembly procedure for Shot Loading Platform  

SciTech Connect

This supporting document describes the assembly procedure for the Shot Loading Platform. The Shot Loading Platform is used by multiple equipment removal projects to load shielding shot in the annular spaces of the equipment storage containers. The platform height is adjustable to accommodate different sizes of storage containers and transport assemblies.

Routh, R.D.

1995-04-01

424

Redevelopment and smart growth at Assembly Square  

E-print Network

The story of Assembly Square is not yet finished. To tell the complete story of Assembly Square would require much more time to write than I had, and more time to read than the reader would likely care to devote. An earlier ...

Savage, Alice (Alice Augusta)

2006-01-01

425

A genetic algorithm for assembly line balancing  

Microsoft Academic Search

Assembly line balancing is a very important aspect in any mass production setup. However, finding the optimal balance is a very difficult proposition because of the computational complexity involved. Hence sub-optimal solutions are preferred over optimal solutions. In this work, a genetic algorithm (GA) is presented for obtaining good quality solutions for assembly line balancing problems. A major feature of

G. SURESH; V. V. VINOD; S. SAHU

1996-01-01

426

Fuel rail assembly and method of fabrication  

Microsoft Academic Search

A fabricated fuel rail assembly for an engine is described. The assembly comprises an elongated sheet metal fuel rail body defining a fuel supply passage and having axially spaced transversely extending fuel injector sockets, the passage intersects the sockets for supplying fuel to the sockets. Each of the sockets receives a fuel injector adapted to deliver fuel from its socket

T. J. Atkins; M. J. Field; D. Nolan

1986-01-01

427

Three-dimensional colorimetric assay assemblies  

DOEpatents

A direct assay is described using novel three-dimensional polymeric assemblies which change from a blue to red color when exposed to an analyte, in one case a flue virus. The assemblies are typically in the form of liposomes which can be maintained in a suspension, and show great intensity in their color changes. Their method of production is also described.

Charych, Deborah (Albany, CA); Reichert, Anke (Albany, CA)

2001-01-01

428

Self-assembly: Served on a nanoplate  

NASA Astrophysics Data System (ADS)

Self-assembled cylinders can generally be extended only from their ends -- growth that is considered to be 'one-dimensional'. Now, platelet-like structures with controlled size and composition have been constructed by growth in two dimensions of self-assembled structures, starting from crystallite seed micelles.

Cai, Chunhua; Lin, Jiaping

2014-10-01

429

Assembly technology of 4-side buttable MPPC  

NASA Astrophysics Data System (ADS)

The multi-pixel photon counter (MPPC) is a solid-state photon counting device consisting of a Geiger-mode APD and a quenching resistor. Through-silicon via technology (TSV) allows for the production of a discrete array version of the MPPC, creating a detector with the advantages of a larger active area and less dead space in its overall packaging when compared to other package types commonly used to produce MPPCs. Eliminating the need for a wire-bonding pad allows individual MPPCs to be tiled with minimum dead-space between individual detectors to form a four-sided buttable array. Selecting MPPCs that behave and perform very similarly to each other, especially when an operating voltage is applied, minimizes variation in performance between each channel and enhances channel uniformity. The output of discrete arrays of MPPCs can be easily readout with ASICs (application specific integrated circuits) due to their excellent channel uniformity characteristics, with minimum adjustment required by the ASIC. TSV-MPPC and assembly technology are developed. TSV-MPPC array is tiled in 4-sided buttable and has large and dense active area. The output pulse of MPPC may have sharp rising edge by virtue of TSV. The uniformity of the array can be maximized by neat inspection technology.

Yamamoto, K.; Sato, K.; Yamada, R.; Hosokawa, N.; Nagano, T.; Hayatsu, K.; Shimohara, T.; Ohkuwa, Y.; Oguri, A.

2013-12-01

430

Method for electrohydrodynamically assembling patterned colloidal structures  

NASA Technical Reports Server (NTRS)

A method apparatus is provided for electrophoretically depositing particles onto an electrode, and electrohydrodynamically assembling the particles into crystalline structures. Specifically, the present method and apparatus creates a current flowing through a solution to cause identically charged electrophoretically deposited colloidal particles to attract each other over very large distances (<5 particle diameters) on the surface of electrodes to form two-dimensional colloidal crystals. The attractive force can be created with both DC and AC fields and can modulated by adjusting either the field strength or frequency of the current. Modulating this lateral attraction between the particles causes the reversible formation of two-dimensional fluid and crystalline colloidal states on the electrode surface. Further manipulation allows for the formation of two or three-dimensional colloidal crystals, as well as more complex designed structures. Once the required structures are formed, these three-dimension colloidal crystals can be permanently frozen or glued by controlled coagulation induced by to the applied field to form a stable crystalline structure.

Trau, Mathias (Inventor); Aksay, Ilhan A. (Inventor); Saville, Dudley A. (Inventor)

1999-01-01

431

Apparatus for electrohydrodynamically assembling patterned colloidal structures  

NASA Technical Reports Server (NTRS)

A method apparatus is provided for electrophoretically depositing particles onto an electrode, and electrohydrodynamically assembling the particles into crystalline structures. Specifically, the present method and apparatus creates a current flowing through a solution to cause identically charged electrophoretically deposited colloidal particles to attract each other over very large distances (<5 particle diameters) on the surface of electrodes to form two-dimensional colloidal crystals. The attractive force can be created with both DC and AC fields and can modulated by adjusting either the field strength or frequency of the current. Modulating this lateral attraction between the particles causes the reversible formation of two-dimensional fluid and crystalline colloidal states on the electrode surface. Further manipulation allows for the formation of two or three-dimensional colloidal crystals, as well as more complex designed structures. Once the required structures are formed, these three-dimension colloidal crystals can be permanently frozen or glued by controlled coagulation induced by to the applied field to form a stable crystalline structure.

Trau, Mathias (Inventor); Aksay, Ilhan A. (Inventor); Saville, Dudley A. (Inventor)

2000-01-01

432

Stochastic self-assembly of incommensurate clusters  

NASA Astrophysics Data System (ADS)

Nucleation and molecular aggregation are important processes in numerous physical and biological systems. In many applications, these processes often take place in confined spaces, involving a finite number of particles. Analogous to treatments of stochastic chemical reactions, we examine the classic problem of homogeneous nucleation and self-assembly by deriving and analyzing a fully discrete stochastic master equation. We enumerate the highest probability steady states, and derive exact analytical formulae for quenched and equilibrium mean cluster size distributions. Upon comparison with results obtained from the associated mass-action Becker-Döring equations, we find striking differences between the two corresponding equilibrium mean cluster concentrations. These differences depend primarily on the divisibility of the total available mass by the maximum allowed cluster size, and the remainder. When such mass "incommensurability" arises, a single remainder particle can "emulsify" the system by significantly broadening the equilibrium mean cluster size distribution. This discreteness-induced broadening effect is periodic in the total mass of the system but arises even when the system size is asymptotically large, provided the ratio of the total mass to the maximum cluster size is finite. Ironically, classic mass-action equations are fairly accurate in the coarsening regime, before equilibrium is reached, despite the presence of large stochastic fluctuations found via kinetic Monte-Carlo simulations. Our findings define a new scaling regime in which results from classic mass-action theories are qualitatively inaccurate, even in the limit of large total system size.

D'Orsogna, M. R.; Lakatos, G.; Chou, T.

2012-02-01

433

Wire-bond inspection in IC assembly  

NASA Astrophysics Data System (ADS)

Wire-bonding in IC assembly process involves making a physical connection between the IC 'die' and the 'lead' by bonding wires between the two. Inspection of wire-bond quality is a' highly labor-intensive process and currently efforts are being made to automate it. This paper presents the results of a research conducted into developing a comprehensive automated wire- bond visual inspection system that is capable of performing final accept/reject inspection, providing on-line process feedback, and assisting in process validation. The proposed inspection system consists of the inspection of the bond on a bond pad, the bond on a lead and the inter-connecting wire between a bond pad and its corresponding lead. The algorithms are based on simple and easily extractable features that ensure achieving the desired accuracy and speed. A novel but simple illumination system is proposed to obtain the images of the inter- connecting wires. The proposed system is validated using several state-of-the-art IC samples. This work is sponsored by the Ministry of Science Technology and Environment, Malaysia and Intel Technology Pvt. Ltd., Malaysia.

Rajeswari, Mandava; Rodd, Mike G.

1996-02-01

434

Forwardly-placed firearm fire control assembly  

DOEpatents

A firearm fire control assembly for disposition in a forwardly placed support-hand operative relationship within a firearm having a combination of a firing pin and a firearm hammer adapted to engage and fire a cartridge, a sear assembly to alternately engage and disengage the combination of the firearm hammer and firing pin, and a trigger assembly including a movable trigger mechanism that is operable to engage the sear assembly to cause the firearm hammer firing pin combination to fire the firearm, a fire control assembly including a fire control depression member and a fire control rod operably connected to the depression member, and being positioned in a forward disposition disposed within a forestock of the firearm, and the depression member adapted to be operably engaged and depressed by the user's conventional forwardly placed support hand to maneuver the fire control rod to provide firing control of the firing of the firearm.

Frickey, Steven J. (Rigby, ID)

2001-12-22

435

Forwardly movable assembly for a firearm  

DOEpatents

A forwardly movable assembly for a firearm, the forwardly movable assembly adapted to be disposed in operative relationship relative to the other operative parts of a firearm, the firearm having in operative relationship each with one or more of the others: a barrel, a receiver, and at least one firing mechanism; the forwardly movable assembly comprising: the barrel and the receiver operatively connected with each other; a movable hand support structure to which at least one of the barrel and the receiver is connected, the barrel being movable therewith, the movable hand support structure being adapted to be gripped by an operator of the firearm; the forwardly movable assembly being adapted to be moved forward by an operator upon gripping the movable hand support structure and manually maneuvering the hand support structure forwardly; and, as the forwardly movable assembly is moved forwardly, the firing mechanism is completely disengaged therefrom and held substantially stationary relative thereto.

Crandall, David L. (Idaho Falls, ID); Watson, Richard W. (Blackfoot, ID)

2007-06-05

436

Modular fuel-cell stack assembly  

DOEpatents

A fuel cell assembly having a plurality of fuel cells arranged in a stack. An end plate assembly abuts the fuel cell at an end of said stack. The end plate assembly has an inlet area adapted to receive an exhaust gas from the stack, an outlet area and a passage connecting the inlet area and outlet area and adapted to carry the exhaust gas received at the inlet area from the inlet area to the outlet area. A further end plate assembly abuts the fuel cell at a further opposing end of the stack. The further end plate assembly has a further inlet area adapted to receive a further exhaust gas from the stack, a further outlet area and a further passage connecting the further inlet area and further outlet area and adapted to carry the further exhaust gas received at the further inlet area from the further inlet area to the further outlet area.

Patel, Pinakin (Danbury, CT)

2010-07-13

437

Programming protein self assembly with coiled coils  

NASA Astrophysics Data System (ADS)

The controlled assembly of protein domains into supramolecular structures will be an important prerequisite for the use of functional proteins in future nanotechnology applications. Coiled coils are multimerization motifs whose dimerization properties can be programmed by amino acid sequence. Here, we report programmed supramolecular self-assembly of protein molecules using coiled coils and directly demonstrate its potential on the single molecule level by AFM force spectroscopy. We flanked two different model proteins, Ig27 from human cardiac titin and green fluorescent protein (GFP), by coiled coil binding partners and studied the capability of these elementary building blocks to self-assemble into linear chains. Simple sterical constraints are shown to control the assembly process, providing evidence that many proteins can be assembled with this method. An application for this technique is the design of polyproteins for single molecule force spectroscopy with an integrated force-calibration standard.

Dietz, Hendrik; Bornschlögl, Thomas; Heym, Roland; König, Frauke; Rief, Matthias

2007-11-01

438

Pneumatic Driven Positioning and Alignment System for the Assembly of Hybrid Microsystems  

E-print Network

Pneumatic Driven Positioning and Alignment System for the Assembly of Hybrid Microsystems Christian assembly, Alignment, Micro Assembly, Micro Gripper, Assembly Head, Positioning, Air Bearing, Pneumatic

Paris-Sud XI, Université de

439

Template-induced structure transition in sub-10 nm self-assembling nanoparticles.  

PubMed

We report on the directed self-assembly of sub-10 nm gold nanoparticles confined within a template comprising channels of gradually varying widths. When the colloidal lattice parameter is mismatched with the channel width, the nanoparticles rearrange and break their natural close-packed ordering, transiting through a range of structural configurations according to the constraints imposed by the channel. While much work has been done in assembling ordered configurations, studies of the transition regime between ordered states have been limited to microparticles under applied compression. Here, with coordinated experiments and Monte Carlo simulations we show that particles transit through a more diverse set of self-assembled configurations than observed for compressed systems. The new insight from this work could lead to the control and design of complex self-assembled patterns other than periodic arrays of ordered particles. PMID:24702584

Asbahi, Mohamed; Mehraeen, Shafigh; Lim, Kevin T P; Wang, Fuke; Cao, Jianshu; Tan, Mei Chee; Yang, Joel K W

2014-05-14

440

Computational design of self-assembling protein nanomaterials with atomic level accuracy  

PubMed Central

We describe a general computational method for designing proteins that self-assemble to a desired symmetric architecture. Protein building blocks are docked together symmetrically to identify complementary packing arrangements, and low-energy protein-protein interfaces are then designed between the building blocks in order to drive self-assembly. Here we use trimeric protein building blocks to design a 24-subunit, 13 nm diameter complex with octahedral symmetry and two related variants of a 12-subunit, 11 nm diameter complex with tetrahedral symmetry. The designed proteins assembled to the desired oligomeric states in solution, and crystal structures of the complexes revealed that the resulting materials closely match the design models. The method can be used to design a wide variety of self-assembling protein nanomaterials. PMID:22654060

King, Neil P.; Sheffler, William; Sawaya, Michael R.; Vollmar, Breanna S.; Sumida, John P.; Andre, Ingemar; Gonen, Tamir; Yeates, Todd O.; Baker, David

2014-01-01

441

PCR - Ligation Assembly Standard for BioBrick Parts  

E-print Network

This Request for Comments (RFC) describes a novel method for the assembly of standard BioBrick parts. This assembly method for BioBrick parts is an improvement upon the conventional methods of BioBrick part assembly. This ...

He, Tony PeiYuan

2011-12-15

442

7 CFR 1755.510 - Construction and assembly unit drawings.  

Code of Federal Regulations, 2010 CFR

... false Construction and assembly unit drawings. 1755.510 Section 1755.510 Agriculture...510 Construction and assembly unit drawings. (a) The construction and assembly unit drawings in this section shall be used by...

2010-01-01

443

An evolutionary fuel assembly design for high power density BWRs  

E-print Network

An evolutionary BWR fuel assembly design was studied as a means to increase the power density of current and future BWR cores. The new assembly concept is based on replacing four traditional assemblies and large water gap ...

Karahan, Aydin

2007-01-01

444

BORED AND ASSEMBLED GATE VALVES RECEIVING PROTECTIVE COATING IN THE ...  

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

BORED AND ASSEMBLED GATE VALVES RECEIVING PROTECTIVE COATING IN THE VALVE PAINT BOOTH OF THE VALVE ASSEMBLY BUILDING. - Stockham Pipe & Fittings Company, Valve Assembly Building, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

445

On-Orbit Assembly of Flexible Space Structures with SWARM  

E-print Network

On-orbit assembly is an enabling technology for many space applications. However, current methods of human assisted assembly are high in cost and risk to the crew, motivating a desire to automate the on-orbit assembly ...

Mohan, Swati

446

Ultrafast gain recovery and modulation limitations in self-assembled quantum-dot devices  

Microsoft Academic Search

Measurements of ultrafast gain recovery in self-assembled InAs quantum-dot (QD) amplifiers are explained by a comprehensive numerical model. The QD excited state carriers are found to act as a reservoir for the optically active ground state carriers resulting in an ultrafast gain recovery as long as the excited state is well populated. However, when pulses are injected into the device

Tommy W. Berg; Svend Bischoff; Ingibjorg Magnusdottir; J. Mork

2001-01-01

447

Emerging Technologies for Assembly of Microscale Hydrogels  

PubMed Central

Assembly of cell encapsulating building blocks (i.e., microscale hydrogels) has significant applications in areas including regenerative medicine, tissue engineering, and cell-based in vitro assays for pharmaceutical research and drug discovery. Inspired by the repeating functional units observed in native tissues and biological systems (e.g., the lobule in liver, the nephron in kidney), assembly technologies aim to generate complex tissue structures by organizing microscale building blocks. Novel assembly technologies enable fabrication of engineered tissue constructs with controlled properties including tunable microarchitectural and predefined compositional features. Recent advances in micro- and nano-scale technologies have enabled engineering of microgel based three dimensional (3D) constructs. There is a need for high-throughput and scalable methods to assemble microscale units with a complex 3D micro-architecture. Emerging assembly methods include novel technologies based on microfluidics, acoustic and magnetic fields, nanotextured surfaces, and surface tension. In this review, we survey emerging microscale hydrogel assembly methods offering rapid, scalable microgel assembly in 3D, and provide future perspectives and discuss potential applications. PMID:23184717

Kavaz, Doga; Demirel, Melik C.; Demirci, Utkan

2013-01-01

448

A classification scheme for LWR fuel assemblies  

SciTech Connect

With over 100 light water nuclear reactors operating nationwide, representing designs by four primary vendors, and with reload fuel manufactured by these vendors and additional suppliers, a wide variety of fuel assembly types are in existence. At Oak Ridge National Laboratory, both the Systems Integration Program and the Characteristics Data Base project required a classification scheme for these fuels. This scheme can be applied to other areas and is expected to be of value to many Office of Civilian Radioactive Waste Management programs. To develop the classification scheme, extensive information on the fuel assemblies that have been and are being manufactured by the various nuclear fuel vendors was compiled, reviewed, and evaluated. It was determined that it is possible to characterize assemblies in a systematic manner, using a combination of physical factors. A two-stage scheme was developed consisting of 79 assembly types, which are grouped into 22 assembly classes. The assembly classes are determined by the general design of the reactor cores in which the assemblies are, or were, used. The general BWR and PWR classes are divided differently but both are based on reactor core configuration. 2 refs., 15 tabs.

Moore, R.S.; Williamson, D.A.; Notz, K.J.

1988-11-01

449

Particle Assembly with Double-Helix DNA  

NASA Astrophysics Data System (ADS)

The use of DNA-functionalized particles and DNA motifs for programmable assembly has been extensively studied in the past decade. However, the majority of the previous successful efforts have been based on a paradigm in which a hybridization of single-stranded DNA(ssDNA)-functionalized particles is utilized to group particles into clusters or large scale assemblies. Here, we report a novel strategy that allows for controllable and programmable assembly of double-stranded DNA (dsDNA)-modified nanoparticles using molecular intercalators. Transmission electron microscopy (TEM), Atomic Force Microscopy (AFM) and dynamic light scattering (DLS), applied to assembled structures, confirm successful assembly of designed clusters using this approach. The efficiency of assembly and thermodynamic properties of formed structures have been also studied. The presented approach is broadly applicable to varieties of existing DNA-based nano-architectures and might provide a platform for development of novel assembly motifs. The potential utility of our approach for a fabrication of complex structures will be also discussed.

Sun, Dazhi Peter; Stadler, Andrea; van der Lelie, Daniel; Gang, Oleg

2010-03-01

450

Flashback resistant pre-mixer assembly  

DOEpatents

A pre-mixer assembly associated with a fuel supply system for mixing of air and fuel upstream from a main combustion zone in a gas turbine engine. The pre-mixer assembly includes a swirler assembly disposed about a fuel injector of the fuel supply system and a pre-mixer transition member. The swirler assembly includes a forward end defining an air inlet and an opposed aft end. The pre-mixer transition member has a forward end affixed to the aft end of the swirler assembly and an opposed aft end defining an outlet of the pre-mixer assembly. The aft end of the pre-mixer transition member is spaced from a base plate such that a gap is formed between the aft end of the pre-mixer transition member and the base plate for permitting a flow of purge air therethrough to increase a velocity of the air/fuel mixture exiting the pre-mixer assembly.

Laster, Walter R. (Oviedo, FL); Gambacorta, Domenico (Oviedo, FL)

2012-02-14

451

Development of a machine vision system for automated structural assembly  

NASA Technical Reports Server (NTRS)

Research is being conducted at the LaRC to develop a telerobotic assembly system designed to construct large space truss structures. This research program was initiated within the past several years, and a ground-based test-bed was developed to evaluate and expand the state of the art. Test-bed operations currently use predetermined ('taught') points for truss structural assembly. Total dependence on the use of taught points for joint receptacle capture and strut installation is neither robust nor reliable enough for space operations. Therefore, a machine vision sensor guidance system is being developed to locate and guide the robot to a passive target mounted on the truss joint receptacle. The vision system hardware includes a miniature video camera, passive targets mounted on the joint receptacles, target illumination hardware, and an image processing system. Discrimination of the target from background clutter is accomplished through standard digital processing techniques. Once the target is identified, a pose estimation algorithm is invoked to determine the location, in three-dimensional space, of the target relative to the robots end-effector. Preliminary test results of the vision system in the Automated Structural Assembly Laboratory with a range of lighting and background conditions indicate that it is fully capable of successfully identifying joint receptacle targets throughout the required operational range. Controlled optical bench test results indicate that the system can also provide the pose estimation accuracy to define the target position.

Sydow, P. Daniel; Cooper, Eric G.

1992-01-01

452

Dispersion Interactions in Molecular Assemblies from First-Principles Calculations  

NASA Astrophysics Data System (ADS)

We have investigated inter-molecular interactions in weakly bonded molecular assemblies from first principles, by combining exact exchange energies (EXX) with correlation energies defined by the adiabatic connection fluctuation-dissipation theorem, within the random phase approximation (RPA)[1,2]. We present results for three different types of molecular systems: the benzene crystal, the methane crystal and self-assembled monolayers of phenylenediisocyanide. We describe in detail how computed equilibrium lattice constants and cohesive energies may be affected by input ground state wave functions and orbital energies, by the geometries of the molecular monomers in the assemblies, and by the inclusion of zero point energy contribution to the total energy. We find that the EXX/RPA perturbative approach provides an overall satisfactory, first principle description of dispersion forces, in good agreement with experiments and advanced quantum chemistry results. However, binding energies tend to be underestimated and possible reasons for this discrepancy are discussed. This work was funded by DOE/BES DE-FG02-06ER46262 and DOE/SciDAC DE-FC02-06ER25794.[1] Y. Li, D. Lu, H-V. Nguyen and G. Galli, J. Phys. Chem.(submitted). [2]D. Lu, Y. Li, D. Rocca and G. Galli, Phys. Rev. Lett. 102, 206411(2009).

Li, Yan; Lu, Deyu; Viet Nguyen, Huy; Galli, Giulia

2010-03-01

453

Problems in understanding the structure and assembly of viruses  

SciTech Connect

Though viruses infect the cells of all groups of animals, plants, and microorganisms, their structures follow a limited number of general themes; spherical or cylindrical shells built of hundreds of repeated protein subunits enclosing a nucleic acid - DNA or RNA - genome. Since the 1960s it has been known that the protein shells of spherical viruses in fact conform to icosahedral symmetry or to subtle deviations from icosahedral symmetry. The construction of the shell lattices and the transformations they go through in the different stages of the viral life cycle are not fully understood. The shells contain the nucleic in a highly condensed state, of unknown coiling/organization. Features of the well studied bacterial viruses will be reviewed, with examples from adenoviruses, herpesviruses, poliovirus, and HIV. The emergence of new viral disease has led to increased interest in the development of agents which interfere with virus reproduction at the level of the assembly or function of the organized particle. Recently computational approaches to the problem of virus assembly have made important contributions to clarifying shell assembly processes. 1 ref.

King, J. [MIT, Cambridge, MA (United States)

1997-12-01

454