Sample records for block structures based

  1. Protein based Block Copolymers

    PubMed Central

    Rabotyagova, Olena S.; Cebe, Peggy; Kaplan, David L.

    2011-01-01

    Advances in genetic engineering have led to the synthesis of protein-based block copolymers with control of chemistry and molecular weight, resulting in unique physical and biological properties. The benefits from incorporating peptide blocks into copolymer designs arise from the fundamental properties of proteins to adopt ordered conformations and to undergo self-assembly, providing control over structure formation at various length scales when compared to conventional block copolymers. This review covers the synthesis, structure, assembly, properties, and applications of protein-based block copolymers. PMID:21235251

  2. Program structure-based blocking

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

    Bertolli, Carlo; Eichenberger, Alexandre E.; O'Brien, John K.

    2017-09-26

    Embodiments relate to program structure-based blocking. An aspect includes receiving source code corresponding to a computer program by a compiler of a computer system. Another aspect includes determining a prefetching section in the source code by a marking module of the compiler. Yet another aspect includes performing, by a blocking module of the compiler, blocking of instructions located in the prefetching section into instruction blocks, such that the instruction blocks of the prefetching section only contain instructions that are located in the prefetching section.

  3. A protein block based fold recognition method for the annotation of twilight zone sequences.

    PubMed

    Suresh, V; Ganesan, K; Parthasarathy, S

    2013-03-01

    The description of protein backbone was recently improved with a group of structural fragments called Structural Alphabets instead of the regular three states (Helix, Sheet and Coil) secondary structure description. Protein Blocks is one of the Structural Alphabets used to describe each and every region of protein backbone including the coil. According to de Brevern (2000) the Protein Blocks has 16 structural fragments and each one has 5 residues in length. Protein Blocks fragments are highly informative among the available Structural Alphabets and it has been used for many applications. Here, we present a protein fold recognition method based on Protein Blocks for the annotation of twilight zone sequences. In our method, we align the predicted Protein Blocks of a query amino acid sequence with a library of assigned Protein Blocks of 953 known folds using the local pair-wise alignment. The alignment results with z-value ≥ 2.5 and P-value ≤ 0.08 are predicted as possible folds. Our method is able to recognize the possible folds for nearly 35.5% of the twilight zone sequences with their predicted Protein Block sequence obtained by pb_prediction, which is available at Protein Block Export server.

  4. Basement structure based on gravity anomaly in the northern Noto peninsula, Central Japan

    NASA Astrophysics Data System (ADS)

    Mizubayashi, T.; Sawada, A.; Hamada, M.; Hiramatsu, Y.; Honda, R.

    2012-12-01

    Upper crustal block structures are usually defined by using surface information, such as geological and morphological data. The northern Noto Peninsula, central Japan, is divided into four geological block structures from tectonic geomorphologic perspectives (Ota and Hirakawa, 1979). This division is based on the surface crustal movement. To image the geological blocks three-dimensionally, it is necessary to construct a subsurface structure model. Gravity survey can clarify the detailed subsurface structure with dense gravity measurement. From the detailed Bouguer anomalies in the northwestern Noto Peninsula, Honda et al. (2008) suggested that the rupture size of the 2007 Noto Hanto earthquake was constrained by the geological block structures. Hiramatsu et al. (2008) also suggested the active faults on the seafloor, such as the source fault of the 2007 Noto Hanto earthquake plays a major role for the formation of the geological block structures. In this study, we analyze subsurface density structure based on the Bouguer anomaly and estimate the distribution of basement depth in the northern Noto Peninsula. We focus the relationship among the basement depth, the block structures and the active faults on the seafloor and discuss the block movement in the northern Noto Peninsula. We compiled the data measured and published previously (Gravity Database of Southwest Japan, 2001; Geological survey of Japan, 2004; Geographical survey institute of Japan, 2006; The Gravity Research Group in Southwest Japan, 2001; Komazawa and Okuma, 2010; Hokuriku electric power Co. Ltd., undisclosed) and calculated Bouguer anomaly in the northern Noto Peninsula. Based on this Bouguer anomaly, we analyzed subsurface density structures along 13 northeastern-southwestern profiles and 35 northwestern-southeastern profiles with the interval of 2 km using the two dimensional Talwani's method (Talwani et al., 1959). In the analysis, we assumed a density structure with four layers: basement (density is 2670kg/m3), Neocene volcanic rock (density is 2400kg/m3, or 2550kg/m3), Neocene sedimentary rock (density is 2200kg/m3), and Quaternary sedimentary rock (density is 1800kg/m3, or 1500kg/m3) (Honda et al., 2008). To compare our basement model to the geological block structures, we focus on a transition zone of the basement depth. We recognize that two of three geological block boundaries correspond to the transition zones. These boundaries also correspond to the boundary of active fault segments on the seafloor. Therefore, based on the relationship between the source fault of the 2007 Noto Hanto earthquake and the geological block, we suggest that the movement of those geological blocks is possibly controlled by the corresponding active fault segments. However, we find that the other block boundary doesn't correspond to the transition zone.

  5. Credit BG. Southeast and northeast facades of concrete block structure ...

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

    Credit BG. Southeast and northeast facades of concrete block structure built in the late 1960s. It is now used to store miscellaneous equipment - Edwards Air Force Base, North Base, Liquid Oxygen Storage Facility, Second Street, Boron, Kern County, CA

  6. Polymer-based platform for microfluidic systems

    DOEpatents

    Benett, William [Livermore, CA; Krulevitch, Peter [Pleasanton, CA; Maghribi, Mariam [Livermore, CA; Hamilton, Julie [Tracy, CA; Rose, Klint [Boston, MA; Wang, Amy W [Oakland, CA

    2009-10-13

    A method of forming a polymer-based microfluidic system platform using network building blocks selected from a set of interconnectable network building blocks, such as wire, pins, blocks, and interconnects. The selected building blocks are interconnectably assembled and fixedly positioned in precise positions in a mold cavity of a mold frame to construct a three-dimensional model construction of a microfluidic flow path network preferably having meso-scale dimensions. A hardenable liquid, such as poly (dimethylsiloxane) is then introduced into the mold cavity and hardened to form a platform structure as well as to mold the microfluidic flow path network having channels, reservoirs and ports. Pre-fabricated elbows, T's and other joints are used to interconnect various building block elements together. After hardening the liquid the building blocks are removed from the platform structure to make available the channels, cavities and ports within the platform structure. Microdevices may be embedded within the cast polymer-based platform, or bonded to the platform structure subsequent to molding, to create an integrated microfluidic system. In this manner, the new microfluidic platform is versatile and capable of quickly generating prototype systems, and could easily be adapted to a manufacturing setting.

  7. Origami-inspired building block and parametric design for mechanical metamaterials

    NASA Astrophysics Data System (ADS)

    Jiang, Wei; Ma, Hua; Feng, Mingde; Yan, Leilei; Wang, Jiafu; Wang, Jun; Qu, Shaobo

    2016-08-01

    An origami-based building block of mechanical metamaterials is proposed and explained by introducing a mechanism model based on its geometry. According to our model, this origami mechanism supports response to uniaxial tension that depends on structure parameters. Hence, its mechanical properties can be tunable by adjusting the structure parameters. Experiments for poly lactic acid (PLA) samples were carried out, and the results are in good agreement with those of finite element analysis (FEA). This work may be useful for designing building blocks of mechanical metamaterials or other complex mechanical structures.

  8. Mechanical Testing of IN718 Lattice Block Structures

    NASA Technical Reports Server (NTRS)

    Krause, David L.; Whittenberger, John D.; Kantzos, Pete T.; Hebsur, Mohan G.

    2002-01-01

    Lattice block construction produces a flat, structurally rigid panel composed of thin ligaments of material arranged in a three-dimensional triangulated truss-like structure. Low-cost methods of producing cast metallic lattice block panels are now available that greatly expand opportunities for using this unique material system in today's high-performance structures. Additional advances are being made in NASA's Ultra Efficient Engine Technology (UEET) program to extend the lattice block concept to superalloy materials. Advantages offered by this combination include high strength, light weight, high stiffness, and elevated temperature capabilities. Recently under UEET, the nickel-based superalloy Inconel 718 (IN718) was investment cast into lattice block panels with great success. To evaluate casting quality and lattice block architecture merit, individual ligaments, and structural subelement specimens were extracted from the panels. Tensile tests, structural compression, and bending strength tests were performed on these specimens. Fatigue testing was also completed for several bend test specimens. This paper first presents metallurgical and optical microscopy analysis of the castings. This is followed by mechanical test results for the tensile ligament tests and the subelement compression and bending strength tests, as well as for the fatigue tests that were performed. These tests generally showed comparable properties to base IN718 with the same heat treatment, and they underscored the benefits offered by lattice block materials. These benefits might be extended with improved architecture such as face sheets.

  9. Tunable Encapsulation Structure of Block Copolymer Coated Single-Walled Carbon Nanotubes in Aqueous Solution

    DOE PAGES

    Han, Youngkyu; Ahn, Suk-Kyun; Zhang, Zhe; ...

    2015-05-15

    The nano-sized and shape-tunable molecular building blocks can provide great opportunities for the fabrication of precisely controlled nanostructures. In this work, we have fabricated a molecular building block of single-walled carbon nanotubes (SWNTs) coated by PPO-PEO-PPO block copolymers whose encapsulation structure can be controlled via temperature or addition of small molecules. The structure and optical properties of SWNT-block copolymers have been investigated by small angle neutron scattering (SANS), ultraviolet-visible (UV-vis) spectroscopy, atomic force microscopy (AFM), and molecular dynamics (MD) simulation. The structure of the hydrated block copolymer layer surrounding SWNT can be controlled reversibly by varying temperature as well asmore » by irreversibly adding 5-methylsalicylic acid (5MS). Increasing hydrophobicity of the polymers with temperature and strong tendency of 5MS to interact with both block copolymers and orbitals of the SWNTs are likely to be responsible for the significant structural change of the block copolymer encapsulation layer, from loose corona shell to tightly encapsulating compact shell. These result shows an efficient and simple way to fabricate and manipulate carbon-based nano building blocks in aqueous systems with tunable structure.« less

  10. Markov prior-based block-matching algorithm for superdimension reconstruction of porous media

    NASA Astrophysics Data System (ADS)

    Li, Yang; He, Xiaohai; Teng, Qizhi; Feng, Junxi; Wu, Xiaohong

    2018-04-01

    A superdimension reconstruction algorithm is used for the reconstruction of three-dimensional (3D) structures of a porous medium based on a single two-dimensional image. The algorithm borrows the concepts of "blocks," "learning," and "dictionary" from learning-based superresolution reconstruction and applies them to the 3D reconstruction of a porous medium. In the neighborhood-matching process of the conventional superdimension reconstruction algorithm, the Euclidean distance is used as a criterion, although it may not really reflect the structural correlation between adjacent blocks in an actual situation. Hence, in this study, regular items are adopted as prior knowledge in the reconstruction process, and a Markov prior-based block-matching algorithm for superdimension reconstruction is developed for more accurate reconstruction. The algorithm simultaneously takes into consideration the probabilistic relationship between the already reconstructed blocks in three different perpendicular directions (x , y , and z ) and the block to be reconstructed, and the maximum value of the probability product of the blocks to be reconstructed (as found in the dictionary for the three directions) is adopted as the basis for the final block selection. Using this approach, the problem of an imprecise spatial structure caused by a point simulation can be overcome. The problem of artifacts in the reconstructed structure is also addressed through the addition of hard data and by neighborhood matching. To verify the improved reconstruction accuracy of the proposed method, the statistical and morphological features of the results from the proposed method and traditional superdimension reconstruction method are compared with those of the target system. The proposed superdimension reconstruction algorithm is confirmed to enable a more accurate reconstruction of the target system while also eliminating artifacts.

  11. Polybenzimidazole block copolymers for fuel cell: synthesis and studies of block length effects on nanophase separation, mechanical properties, and proton conductivity of PEM.

    PubMed

    Maity, Sudhangshu; Jana, Tushar

    2014-05-14

    A series of meta-polybenzimidazole-block-para-polybenzimidazole (m-PBI-b-p-PBI), segmented block copolymers of PBI, were synthesized with various structural motifs and block lengths by condensing the diamine terminated meta-PBI (m-PBI-Am) and acid terminated para-PBI (p-PBI-Ac) oligomers. NMR studies and existence of two distinct glass transition temperatures (Tg), obtained from dynamical mechanical analysis (DMA) results, unequivocally confirmed the formation of block copolymer structure through the current polymerization methodology. Appropriate and careful selection of oligomers chain length enabled us to tailor the block length of block copolymers and also to make varieties of structural motifs. Increasingly distinct Tg peaks with higher block length of segmented block structure attributed the decrease in phase mixing between the meta-PBI and para-PBI blocks, which in turn resulted into nanophase segregated domains. The proton conductivities of proton exchange membrane (PEM) developed from phosphoric acid (PA) doped block copolymer membranes were found to be increasing substantially with increasing block length of copolymers even though PA loading of these membranes did not alter appreciably with varying block length. For example when molecular weight (Mn) of blocks were increased from 1000 to 5500 then the proton conductivities at 160 °C of resulting copolymers increased from 0.05 to 0.11 S/cm. Higher block length induced nanophase separation between the blocks by creating less morphological barrier within the block which facilitated the movement of the proton in the block and hence resulting higher proton conductivity of the PEM. The structural varieties also influenced the phase separation and proton conductivity. In comparison to meta-para random copolymers reported earlier, the current meta-para segmented block copolymers were found to be more suitable for PBI-based PEM.

  12. An adaptive block-based fusion method with LUE-SSIM for multi-focus images

    NASA Astrophysics Data System (ADS)

    Zheng, Jianing; Guo, Yongcai; Huang, Yukun

    2016-09-01

    Because of the lenses' limited depth of field, digital cameras are incapable of acquiring an all-in-focus image of objects at varying distances in a scene. Multi-focus image fusion technique can effectively solve this problem. Aiming at the block-based multi-focus image fusion methods, the problem that blocking-artifacts often occurs. An Adaptive block-based fusion method based on lifting undistorted-edge structural similarity (LUE-SSIM) is put forward. In this method, image quality metrics LUE-SSIM is firstly proposed, which utilizes the characteristics of human visual system (HVS) and structural similarity (SSIM) to make the metrics consistent with the human visual perception. Particle swarm optimization(PSO) algorithm which selects LUE-SSIM as the object function is used for optimizing the block size to construct the fused image. Experimental results on LIVE image database shows that LUE-SSIM outperform SSIM on Gaussian defocus blur images quality assessment. Besides, multi-focus image fusion experiment is carried out to verify our proposed image fusion method in terms of visual and quantitative evaluation. The results show that the proposed method performs better than some other block-based methods, especially in reducing the blocking-artifact of the fused image. And our method can effectively preserve the undistorted-edge details in focus region of the source images.

  13. De novo design of molecular architectures by evolutionary assembly of drug-derived building blocks.

    PubMed

    Schneider, G; Lee, M L; Stahl, M; Schneider, P

    2000-07-01

    An evolutionary algorithm was developed for fragment-based de novo design of molecules (TOPAS, TOPology-Assigning System). This stochastic method aims at generating a novel molecular structure mimicking a template structure. A set of approximately 25,000 fragment structures serves as the building block supply, which were obtained by a straightforward fragmentation procedure applied to 36,000 known drugs. Eleven reaction schemes were implemented for both fragmentation and building block assembly. This combination of drug-derived building blocks and a restricted set of reaction schemes proved to be a key for the automatic development of novel, synthetically tractable structures. In a cyclic optimization process, molecular architectures were generated from a parent structure by virtual synthesis, and the best structure of a generation was selected as the parent for the subsequent TOPAS cycle. Similarity measures were used to define 'fitness', based on 2D-structural similarity or topological pharmacophore distance between the template molecule and the variants. The concept of varying library 'diversity' during a design process was consequently implemented by using adaptive variant distributions. The efficiency of the design algorithm was demonstrated for the de novo construction of potential thrombin inhibitors mimicking peptide and non-peptide template structures.

  14. Gaussian curvature analysis allows for automatic block placement in multi-block hexahedral meshing.

    PubMed

    Ramme, Austin J; Shivanna, Kiran H; Magnotta, Vincent A; Grosland, Nicole M

    2011-10-01

    Musculoskeletal finite element analysis (FEA) has been essential to research in orthopaedic biomechanics. The generation of a volumetric mesh is often the most challenging step in a FEA. Hexahedral meshing tools that are based on a multi-block approach rely on the manual placement of building blocks for their mesh generation scheme. We hypothesise that Gaussian curvature analysis could be used to automatically develop a building block structure for multi-block hexahedral mesh generation. The Automated Building Block Algorithm incorporates principles from differential geometry, combinatorics, statistical analysis and computer science to automatically generate a building block structure to represent a given surface without prior information. We have applied this algorithm to 29 bones of varying geometries and successfully generated a usable mesh in all cases. This work represents a significant advancement in automating the definition of building blocks.

  15. Algorithms for the automatic generation of 2-D structured multi-block grids

    NASA Technical Reports Server (NTRS)

    Schoenfeld, Thilo; Weinerfelt, Per; Jenssen, Carl B.

    1995-01-01

    Two different approaches to the fully automatic generation of structured multi-block grids in two dimensions are presented. The work aims to simplify the user interactivity necessary for the definition of a multiple block grid topology. The first approach is based on an advancing front method commonly used for the generation of unstructured grids. The original algorithm has been modified toward the generation of large quadrilateral elements. The second method is based on the divide-and-conquer paradigm with the global domain recursively partitioned into sub-domains. For either method each of the resulting blocks is then meshed using transfinite interpolation and elliptic smoothing. The applicability of these methods to practical problems is demonstrated for typical geometries of fluid dynamics.

  16. Superalloy Lattice Block Structures

    NASA Technical Reports Server (NTRS)

    Whittenberger, J. D.; Nathal, M. V.; Hebsur, M. G.; Kraus, D. L.

    2003-01-01

    In their simplest form, lattice block panels are produced by direct casting and result in lightweight, fully triangulated truss-like configurations which provide strength and stiffness [2]. The earliest realizations of lattice block were made from A1 and steels, primarily under funding from the US Navy [3]. This work also showed that the mechanical efficiency (eg., specific stiffness) of lattice block structures approached that of honeycomb structures [2]. The lattice architectures are also less anisotropic, and the investment casting route should provide a large advantage in cost and temperature capability over honeycombs which are limited to alloys that can be processed into foils. Based on this early work, a program was initiated to determine the feasibility of extending the high temperature superalloy lattice block [3]. The objective of this effort was to provide an alternative to intermetallics and composites in achieving a lightweight high temperature structure without sacrificing the damage tolerance and moderate cost inherent in superalloys. To establish the feasibility of the superalloy lattice block concept, work was performed in conjunction with JAMCORP, Inc. Billerica, MA, to produce a number of lattice block panels from both IN71 8 and Mar-M247.

  17. North-South contraction of the mojave block and strike-slip tectonics in southern california.

    PubMed

    Bartley, J M; Glazner, A F; Schermer, E R

    1990-06-15

    The Mojave block of southern California has undergone significant late Cenozoic north-south contraction. This previously unappreciated deformation may account for part of the discrepancy between neotectonic and plate-tectonic estimates of Pacific-North American plate motion, and for part of the Big Bend in the San Andreas fault. In the eastern Mojave block, contraction is superimposed on early Miocene crustal extension. In the western Mojave block, contractional folds and reverse faults have been mistaken for extensional structures. The three-dimensional complexity of the contractional structures may mean that rigid-block tectonic models of the region based primarily on paleomagnetic data are unreliable.

  18. Structural design principles for delivery of bioactive components in nutraceuticals and functional foods.

    PubMed

    McClements, David Julian; Decker, Eric Andrew; Park, Yeonhwa; Weiss, Jochen

    2009-06-01

    There have been major advances in the design and fabrication of structured delivery systems for the encapsulation of nutraceutical and functional food components. A wide variety of delivery systems is now available, each with its own advantages and disadvantages for particular applications. This review begins by discussing some of the major nutraceutical and functional food components that need to be delivered and highlights the main limitations to their current utilization within the food industry. It then discusses the principles underpinning the rational design of structured delivery systems: the structural characteristics of the building blocks; the nature of the forces holding these building blocks together; and, the different ways of assembling these building blocks into structured delivery systems. Finally, we review the major types of structured delivery systems that are currently available to food scientists: lipid-based (simple, multiple, multilayer, and solid lipid particle emulsions); surfactant-based (simple micelles, mixed micelles, vesicles, and microemulsions) and biopolymer-based (soluble complexes, coacervates, hydrogel droplets, and particles). For each type of delivery system we describe its preparation, properties, advantages, and limitations.

  19. Polymer compositions based on PXE

    DOEpatents

    Yang, Jin; Eitouni, Hany Basam; Singh, Mohit

    2015-09-15

    New polymer compositions based on poly(2,6-dimethyl-1,4-phenylene oxide) and other high-softening-temperature polymers are disclosed. These materials have a microphase domain structure that has an ionically-conductive phase and a phase with good mechanical strength and a high softening temperature. In one arrangement, the structural block has a softening temperature of about 210.degree. C. These materials can be made with either homopolymers or with block copolymers.

  20. Revitalizing problem based learning: student and tutor attitudes towards a structured tutorial.

    PubMed

    Espey, Eve; Ogburn, Tony; Kalishman, Summers; Zsemlye, Meggan; Cosgrove, Ellen

    2007-03-01

    The pre-clinical curriculum at the University of New Mexico School of Medicine is a hybrid model that includes small group, problem-based learning (PBL) tutorials and didactic lectures. A structured tutorial format was piloted for the human sexuality/reproduction organ system block for the PBL component. The objective of this study was to compare the acceptability of the structured format and its effectiveness with that of a traditional PBL tutorial. Students were surveyed after the renal/endocrinology block of 2004 (traditional tutorial format) and after the human sexuality/reproduction block of 2004 (structured tutorial format) (n = 70). Survey questions covered the quality of learning and of tutorial. Students (n = 132) and tutors (n = 24) who participated in human sexuality/reproduction in 2004 and 2005 were surveyed for attitudes about the structured tutorial overall and specific components. Means of responses were compared using t-tests. Students indicated that the structured tutorial format supported a greater improvement in their basic science and clinical knowledge and their ability to evaluate information (p < 0.05). The majority of students and tutors recommended the structured format for tutorials in other blocks. We demonstrated the acceptability of a structured tutorial format to students and faculty. Faculty members perceived greater depth of learning and participation by the students.

  1. Two innovative solutions based on fibre concrete blocks designed for building substructure

    NASA Astrophysics Data System (ADS)

    Pazderka, J.; Hájek, P.

    2017-09-01

    Using of fibers in a high-strength concrete allows reduction of the dimensions of small precast concrete elements, which opens up new ways of solution for traditional construction details in buildings. The paper presents two innovative technical solutions for building substructure: The special shaped plinth block from fibre concrete and the fibre concrete elements for new technical solution of ventilated floor. The main advantages of plinth block from fibre concrete blocks (compared with standard plinth solutions) is: easier and faster assembly, higher durability and thanks to the air cavity between the vertical part of the block, the building substructure reduced moisture level of structures under the waterproofing layer and a comprehensive solution to the final surface of building plinth as well as the surface of adjacent terrain. The ventilated floor based on fibre concrete precast blocks is an attractive structural alternative for tackling the problem of increased moisture in masonry in older buildings, lacking a functional waterproof layer in the substructure.

  2. Novel Self-Assembling Amino Acid-Derived Block Copolymer with Changeable Polymer Backbone Structure.

    PubMed

    Koga, Tomoyuki; Aso, Eri; Higashi, Nobuyuki

    2016-11-29

    Block copolymers have attracted much attention as potentially interesting building blocks for the development of novel nanostructured materials in recent years. Herein, we report a new type of self-assembling block copolymer with changeable polymer backbone structure, poly(Fmoc-Ser) ester -b-PSt, which was synthesized by combining the polycondensation of 9-fluorenylmethoxycarbonyl-serine (Fmoc-Ser) with the reversible addition-fragmentation chain transfer (RAFT) polymerization of styrene (St). This block copolymer showed the direct conversion of the backbone structure from polyester to polypeptide through a multi O,N-acyl migration triggered by base-induced deprotection of Fmoc groups in organic solvent. Such polymer-to-polymer conversion was found to occur quantitatively without decrease in degree of polymerization and to cause a drastic change in self-assembling property of the block copolymer. On the basis of several morphological analyses using FTIR spectroscopy, atomic force, and transmission and scanning electron microscopies, the resulting peptide block copolymer was found to self-assemble into a vesicle-like hollow nanosphere with relatively uniform diameter of ca. 300 nm in toluene. In this case, the peptide block generated from polyester formed β-sheet structure, indicating the self-assembly via peptide-guided route. We believe the findings presented in this study offer a new concept for the development of self-assembling block copolymer system.

  3. Initial Mechanical Testing of Superalloy Lattice Block Structures Conducted

    NASA Technical Reports Server (NTRS)

    Krause, David L.; Whittenberger, J. Daniel

    2002-01-01

    The first mechanical tests of superalloy lattice block structures produced promising results for this exciting new lightweight material system. The testing was performed in-house at NASA Glenn Research Center's Structural Benchmark Test Facility, where small subelement-sized compression and beam specimens were loaded to observe elastic and plastic behavior, component strength levels, and fatigue resistance for hundreds of thousands of load cycles. Current lattice block construction produces a flat panel composed of thin ligaments arranged in a three-dimensional triangulated trusslike structure. Investment casting of lattice block panels has been developed and greatly expands opportunities for using this unique architecture in today's high-performance structures. In addition, advances made in NASA's Ultra-Efficient Engine Technology Program have extended the lattice block concept to superalloy materials. After a series of casting iterations, the nickel-based superalloy Inconel 718 (IN 718, Inco Alloys International, Inc., Huntington, WV) was successfully cast into lattice block panels; this combination offers light weight combined with high strength, high stiffness, and elevated-temperature durability. For tests to evaluate casting quality and configuration merit, small structural compression and bend test specimens were machined from the 5- by 12- by 0.5-in. panels. Linear elastic finite element analyses were completed for several specimen layouts to predict material stresses and deflections under proposed test conditions. The structural specimens were then subjected to room-temperature static and cyclic loads in Glenn's Life Prediction Branch's material test machine. Surprisingly, the test results exceeded analytical predictions: plastic strains greater than 5 percent were obtained, and fatigue lives did not depreciate relative to the base material. These assets were due to the formation of plastic hinges and the redundancies inherent in lattice block construction, which were not considered in the simplified computer models. The fatigue testing proved the value of redundancies since specimen strength was maintained even after the fracture of one or two ligaments. This ongoing test program is planned to continue through high-temperature testing. Also scheduled for testing are IN 718 lattice block panels with integral face sheets, as well as specimens cast from a higher temperature alloy. The initial testing suggests the value of this technology for large panels under low and moderate pressure loadings and for high-risk, damage-tolerant structures. Potential aeropropulsion uses for lattice blocks include turbine-engine actuated panels, exhaust nozzle flaps, and side panel structures.

  4. Total synthesis of TMG-chitotriomycin based on an automated electrochemical assembly of a disaccharide building block.

    PubMed

    Isoda, Yuta; Sasaki, Norihiko; Kitamura, Kei; Takahashi, Shuji; Manmode, Sujit; Takeda-Okuda, Naoko; Tamura, Jun-Ichi; Nokami, Toshiki; Itoh, Toshiyuki

    2017-01-01

    The total synthesis of TMG-chitotriomycin using an automated electrochemical synthesizer for the assembly of carbohydrate building blocks is demonstrated. We have successfully prepared a precursor of TMG-chitotriomycin, which is a structurally-pure tetrasaccharide with typical protecting groups, through the methodology of automated electrochemical solution-phase synthesis developed by us. The synthesis of structurally well-defined TMG-chitotriomycin has been accomplished in 10-steps from a disaccharide building block.

  5. Structure-Preserving Smoothing of Biomedical Images

    NASA Astrophysics Data System (ADS)

    Gil, Debora; Hernàndez-Sabaté, Aura; Burnat, Mireia; Jansen, Steven; Martínez-Villalta, Jordi

    Smoothing of biomedical images should preserve gray-level transitions between adjacent tissues, while restoring contours consistent with anatomical structures. Anisotropic diffusion operators are based on image appearance discontinuities (either local or contextual) and might fail at weak inter-tissue transitions. Meanwhile, the output of block-wise and morphological operations is prone to present a block structure due to the shape and size of the considered pixel neighborhood.

  6. Total synthesis of TMG-chitotriomycin based on an automated electrochemical assembly of a disaccharide building block

    PubMed Central

    Isoda, Yuta; Sasaki, Norihiko; Kitamura, Kei; Takahashi, Shuji; Manmode, Sujit; Takeda-Okuda, Naoko; Tamura, Jun-ichi

    2017-01-01

    The total synthesis of TMG-chitotriomycin using an automated electrochemical synthesizer for the assembly of carbohydrate building blocks is demonstrated. We have successfully prepared a precursor of TMG-chitotriomycin, which is a structurally-pure tetrasaccharide with typical protecting groups, through the methodology of automated electrochemical solution-phase synthesis developed by us. The synthesis of structurally well-defined TMG-chitotriomycin has been accomplished in 10-steps from a disaccharide building block. PMID:28684973

  7. Numerical analysis and comparison of three types of herringbone frame structure for highway subgrade slopes protection

    NASA Astrophysics Data System (ADS)

    Nie, Yihua; Tang, Saiqian; Xu, Yang; Mao, Kunli

    2018-04-01

    In order to obtain mechanical response distribution of herringbone frame structure for highway subgrade slopes protection and select the best structure type, 3D numerical models of three types herringbone frame structure were established and analyzed in finite element software ANSYS. Indoor physical model of soil slope protected by herringbone frame structure was built and mechanical response of the frame structure was measured by loading tests. Numerical results indicate slope foot is the stress most disadvantageous location. Comparative analysis shows that structure composed of mortar rubble base layer and precast concrete blocks paving layer is the best one for resisting deformation and structure with cement mortar base layer and precast concrete blocks paving layer is the best one for being of low stress.

  8. Minimum Description Length Block Finder, a Method to Identify Haplotype Blocks and to Compare the Strength of Block Boundaries

    PubMed Central

    Mannila, H.; Koivisto, M.; Perola, M.; Varilo, T.; Hennah, W.; Ekelund, J.; Lukk, M.; Peltonen, L.; Ukkonen, E.

    2003-01-01

    We describe a new probabilistic method for finding haplotype blocks that is based on the use of the minimum description length (MDL) principle. We give a rigorous definition of the quality of a segmentation of a genomic region into blocks and describe a dynamic programming algorithm for finding the optimal segmentation with respect to this measure. We also describe a method for finding the probability of a block boundary for each pair of adjacent markers: this gives a tool for evaluating the significance of each block boundary. We have applied the method to the published data of Daly and colleagues. The results expose some problems that exist in the current methods for the evaluation of the significance of predicted block boundaries. Our method, MDL block finder, can be used to compare block borders in different sample sets, and we demonstrate this by applying the MDL-based method to define the block structure in chromosomes from population isolates. PMID:12761696

  9. Minimum description length block finder, a method to identify haplotype blocks and to compare the strength of block boundaries.

    PubMed

    Mannila, H; Koivisto, M; Perola, M; Varilo, T; Hennah, W; Ekelund, J; Lukk, M; Peltonen, L; Ukkonen, E

    2003-07-01

    We describe a new probabilistic method for finding haplotype blocks that is based on the use of the minimum description length (MDL) principle. We give a rigorous definition of the quality of a segmentation of a genomic region into blocks and describe a dynamic programming algorithm for finding the optimal segmentation with respect to this measure. We also describe a method for finding the probability of a block boundary for each pair of adjacent markers: this gives a tool for evaluating the significance of each block boundary. We have applied the method to the published data of Daly and colleagues. The results expose some problems that exist in the current methods for the evaluation of the significance of predicted block boundaries. Our method, MDL block finder, can be used to compare block borders in different sample sets, and we demonstrate this by applying the MDL-based method to define the block structure in chromosomes from population isolates.

  10. Restructuring a basic science course for core competencies: an example from anatomy teaching.

    PubMed

    Gregory, Jeremy K; Lachman, Nirusha; Camp, Christopher L; Chen, Laura P; Pawlina, Wojciech

    2009-09-01

    Medical schools revise their curricula in order to develop physicians best skilled to serve the public's needs. To ensure a smooth transition to residency programs, undergraduate medical education is often driven by the six core competencies endorsed by the Accreditation Council for Graduate Medical Education (ACGME): patient care, medical knowledge, practice-based learning, interpersonal skills, professionalism, and systems-based practice. Recent curricular redesign at Mayo Medical School provided an opportunity to restructure anatomy education and integrate radiology with first-year gross and developmental anatomy. The resulting 6-week (120-contact-hour) human structure block provides students with opportunities to learn gross anatomy through dissection, radiologic imaging, and embryologic correlation. We report more than 20 educational interventions from the human structure block that may serve as a model for incorporating the ACGME core competencies into basic science and early medical education. The block emphasizes clinically-oriented anatomy, invites self- and peer-evaluation, provides daily formative feedback through an audience response system, and employs team-based learning. The course includes didactic briefing sessions and roles for students as teachers, leaders, and collaborators. Third-year medical students serve as teaching assistants. With its clinical focus and competency-based design, the human structure block connects basic science with best-practice clinical medicine.

  11. Block-structured grids for complex aerodynamic configurations: Current status

    NASA Technical Reports Server (NTRS)

    Vatsa, Veer N.; Sanetrik, Mark D.; Parlette, Edward B.

    1995-01-01

    The status of CFD methods based on the use of block-structured grids for analyzing viscous flows over complex configurations is examined. The objective of the present study is to make a realistic assessment of the usability of such grids for routine computations typically encountered in the aerospace industry. It is recognized at the very outset that the total turnaround time, from the moment the configuration is identified until the computational results have been obtained and postprocessed, is more important than just the computational time. Pertinent examples will be cited to demonstrate the feasibility of solving flow over practical configurations of current interest on block-structured grids.

  12. Lightweight Structures

    NASA Technical Reports Server (NTRS)

    Whittenberger, J. Daniel

    2001-01-01

    Present structural concepts for hot static structures are conventional "sheet & stringer" or truss core construction. More weight-efficient concepts such as honeycomb and lattice block are being investigated, in combination with both conventional superalloys and TiAl. Development efforts for components made from TiAl sheet are centered on lower cost methods for sheet and foil production, plus alloy development for higher temperature capability. A low-cost casting technology recently developed for aluminum and steel lattice blocks has demonstrated the required higher strength and stiffness, with weight efficiency approach- ing honeycombs. The current effort is based on extending the temperature capability by developing lattice block materials made from IN-718 and Mar-M247.

  13. A novel fractal image compression scheme with block classification and sorting based on Pearson's correlation coefficient.

    PubMed

    Wang, Jianji; Zheng, Nanning

    2013-09-01

    Fractal image compression (FIC) is an image coding technology based on the local similarity of image structure. It is widely used in many fields such as image retrieval, image denoising, image authentication, and encryption. FIC, however, suffers from the high computational complexity in encoding. Although many schemes are published to speed up encoding, they do not easily satisfy the encoding time or the reconstructed image quality requirements. In this paper, a new FIC scheme is proposed based on the fact that the affine similarity between two blocks in FIC is equivalent to the absolute value of Pearson's correlation coefficient (APCC) between them. First, all blocks in the range and domain pools are chosen and classified using an APCC-based block classification method to increase the matching probability. Second, by sorting the domain blocks with respect to APCCs between these domain blocks and a preset block in each class, the matching domain block for a range block can be searched in the selected domain set in which these APCCs are closer to APCC between the range block and the preset block. Experimental results show that the proposed scheme can significantly speed up the encoding process in FIC while preserving the reconstructed image quality well.

  14. SU-F-T-436: A Method to Evaluate Dosimetric Properties of SFGRT in Eclipse TPS

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

    Xu, M; Tobias, R; Pankuch, M

    Purpose: The objective was to develop a method for dose distribution calculation of spatially-fractionated-GRID-radiotherapy (SFGRT) in Eclipse treatment-planning-system (TPS). Methods: Patient treatment-plans with SFGRT for bulky tumors were generated in Varian Eclipse version11. A virtual structure based on the GRID pattern was created and registered to a patient CT image dataset. The virtual GRID structure was positioned on the iso-center level together with matching beam geometries to simulate a commercially available GRID block made of brass. This method overcame the difficulty in treatment-planning and dose-calculation due to the lack o-the option to insert a GRID block add-on in Eclipse TPS.more » The patient treatment-planning displayed GRID effects on the target, critical structures, and dose distribution. The dose calculations were compared to the measurement results in phantom. Results: The GRID block structure was created to follow the beam divergence to the patient CT images. The inserted virtual GRID block made it possible to calculate the dose distributions and profiles at various depths in Eclipse. The virtual GRID block was added as an option to TPS. The 3D representation of the isodose distribution of the spatially-fractionated beam was generated in axial, coronal, and sagittal planes. Physics of GRID can be different from that for fields shaped by regular blocks because the charge-particle-equilibrium cannot be guaranteed for small field openings. Output factor (OF) measurement was required to calculate the MU to deliver the prescribed dose. The calculated OF based on the virtual GRID agreed well with the measured OF in phantom. Conclusion: The method to create the virtual GRID block has been proposed for the first time in Eclipse TPS. The dosedistributions, in-plane and cross-plane profiles in PTV can be displayed in 3D-space. The calculated OF’s based on the virtual GRID model compare well to the measured OF’s for SFGRT clinical use.« less

  15. Nanoscale superstructures assembled by polymerase chain reaction (PCR): programmable construction, structural diversity, and emerging applications.

    PubMed

    Kuang, Hua; Ma, Wei; Xu, Liguang; Wang, Libing; Xu, Chuanlai

    2013-11-19

    Polymerase chain reaction (PCR) is an essential tool in biotechnology laboratories and is becoming increasingly important in other areas of research. Extensive data obtained over the last 12 years has shown that the combination of PCR with nanoscale dispersions can resolve issues in the preparation DNA-based materials that include both inorganic and organic nanoscale components. Unlike conventional DNA hybridization and antibody-antigen complexes, PCR provides a new, effective assembly platform that both increases the yield of DNA-based nanomaterials and allows researchers to program and control assembly with predesigned parameters including those assisted and automated by computers. As a result, this method allows researchers to optimize to the combinatorial selection of the DNA strands for their nanoparticle conjugates. We have developed a PCR approach for producing various nanoscale assemblies including organic motifs such as small molecules, macromolecules, and inorganic building blocks, such as nanorods (NRs), metal, semiconductor, and magnetic nanoparticles (NPs). We start with a nanoscale primer and then modify that building block using the automated steps of PCR-based assembly including initialization, denaturation, annealing, extension, final elongation, and final hold. The intermediate steps of denaturation, annealing, and extension are cyclic, and we use computer control so that the assembled superstructures reach their predetermined complexity. The structures assembled using a small number of PCR cycles show a lower polydispersity than similar discrete structures obtained by direct hybridization between the nanoscale building blocks. Using different building blocks, we assembled the following structural motifs by PCR: (1) discrete nanostructures (NP dimers, NP multimers including trimers, pyramids, tetramers or hexamers, etc.), (2) branched NP superstructures and heterochains, (3) NP satellite-like superstructures, (4) Y-shaped nanostructures and DNA networks, (5) protein-DNA co-assembly structures, and (6) DNA block copolymers including trimers and pentamers. These results affirm that this method can produce a variety of chemical structures and in yields that are tunable. Using PCR-based preparation of DNA-bridged nanostructures, we can program the assembly of the nanoscale blocks through the adjustment of the primer intensity on the assembled units, the number of PCR cycles, or both. The resulting structures are highly complex and diverse and have interesting dynamics and collective properties. Potential applications of these materials include chirooptical materials, probe fabrication, and environmental and biomedical sensors.

  16. Kinetic control of block copolymer self-assembly into multicompartment and novel geometry nanoparticles

    NASA Astrophysics Data System (ADS)

    Chen, Yingchao; Wang, Xiaojun; Zhang, Ke; Wooley, Karen; Mays, Jimmy; Percec, Virgil; Pochan, Darrin

    2012-02-01

    Micelles with the segregation of hydrophobic blocks trapped in the same nanoparticle core have been produced through co-self-assembly of two block copolymers in THF/water dilute solution. The dissolution of two block copolymer sharing the same polyacrylic acid PAA blocks in THF undergoes consequent aggregation and phase separation through either slow water titration or quick water addition that triggers the micellar formation. The combination and comparison of the two water addition kinetic pathways are the keys of forming multicompartment structures at high water content. Importantly, the addition of organic diamine provides for acid-base complexation with the PAA side chains which, in turn, plays the key role of trapping unlike hydrophobic blocks from different block copolymers into one nanoparticle core. The kinetic control of solution assembly can be applied to other molecular systems such as dendrimers as well as other block copolymer molecules. Transmission electron microscopy, cryogenic transmission electron microscopy, light scattering have been applied to characterize the micelle structures.

  17. Novel Near-Lossless Compression Algorithm for Medical Sequence Images with Adaptive Block-Based Spatial Prediction.

    PubMed

    Song, Xiaoying; Huang, Qijun; Chang, Sheng; He, Jin; Wang, Hao

    2016-12-01

    To address the low compression efficiency of lossless compression and the low image quality of general near-lossless compression, a novel near-lossless compression algorithm based on adaptive spatial prediction is proposed for medical sequence images for possible diagnostic use in this paper. The proposed method employs adaptive block size-based spatial prediction to predict blocks directly in the spatial domain and Lossless Hadamard Transform before quantization to improve the quality of reconstructed images. The block-based prediction breaks the pixel neighborhood constraint and takes full advantage of the local spatial correlations found in medical images. The adaptive block size guarantees a more rational division of images and the improved use of the local structure. The results indicate that the proposed algorithm can efficiently compress medical images and produces a better peak signal-to-noise ratio (PSNR) under the same pre-defined distortion than other near-lossless methods.

  18. An efficient predictor-corrector-based dynamic mesh method for multi-block structured grid with extremely large deformation and its applications

    NASA Astrophysics Data System (ADS)

    Guo, Tongqing; Chen, Hao; Lu, Zhiliang

    2018-05-01

    Aiming at extremely large deformation, a novel predictor-corrector-based dynamic mesh method for multi-block structured grid is proposed. In this work, the dynamic mesh generation is completed in three steps. At first, some typical dynamic positions are selected and high-quality multi-block grids with the same topology are generated at those positions. Then, Lagrange interpolation method is adopted to predict the dynamic mesh at any dynamic position. Finally, a rapid elastic deforming technique is used to correct the small deviation between the interpolated geometric configuration and the actual instantaneous one. Compared with the traditional methods, the results demonstrate that the present method shows stronger deformation ability and higher dynamic mesh quality.

  19. Olefinic Thermoplastic Elastomer Gels: Combining Polymer Crystallization and Microphase Separation in a Selective Solvent

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

    Armstrong, Daniel P.; Mineart, Kenneth P.; Lee, Byeongdu

    Since selectively swollen thermoplastic elastomer gels (TPEGs) afford a wide range of beneficial properties that open new doors to developing elastomer-based technologies, in this study we examine the unique structure-property behavior of TPEGs composed of olefinic block copolymers (OBCs). Unlike their styrenic counterparts typically possessing two chemically different blocks, this class of multiblock copolymers consists of linear polyethylene hard blocks and poly(ethylene-co-α-octene) soft blocks, in which case, microphase separation between the hard and the soft blocks is accompanied by crystallization of the hard blocks. We prepare olefinic TPEGs (OTPEGs) through the incorporation of a primarily aliphatic oil that selectively swellsmore » the soft block and investigate the resultant morphological features through the use of polarized light microscopy and small-/wideangle X-ray scattering. These features are correlated with thermal and mechanical property measurements from calorimetry, rheology, and extensiometry to elucidate the roles of crystallization and self-assembly on gel characteristics and establish useful structure-property relationships.« less

  20. Olefinic Thermoplastic Elastomer Gels: Combining Polymer Crystallization and Microphase Separation in a Selective Solvent

    DOE PAGES

    Armstrong, Daniel P.; Mineart, Kenneth P.; Lee, Byeongdu; ...

    2016-11-01

    Since selectively swollen thermoplastic elastomer gels (TPEGs) afford a wide range of beneficial properties that open new doors to developing elastomer-based technologies, in this study we examine the unique structure-property behavior of TPEGs composed of olefinic block copolymers (OBCs). Unlike their styrenic counterparts typically possessing two chemically different blocks, this class of multiblock copolymers consists of linear polyethylene hard blocks and poly(ethylene-co-α-octene) soft blocks, in which case, microphase separation between the hard and the soft blocks is accompanied by crystallization of the hard blocks. We prepare olefinic TPEGs (OTPEGs) through the incorporation of a primarily aliphatic oil that selectively swellsmore » the soft block and investigate the resultant morphological features through the use of polarized light microscopy and small-/wideangle X-ray scattering. These features are correlated with thermal and mechanical property measurements from calorimetry, rheology, and extensiometry to elucidate the roles of crystallization and self-assembly on gel characteristics and establish useful structure-property relationships.« less

  1. Effects of Interlocking and Supporting Conditions on Concrete Block Pavements

    NASA Astrophysics Data System (ADS)

    Mahapatra, Geetimukta; Kalita, Kuldeep

    2018-02-01

    Concrete Block Paving (CBP) is widely used as wearing course in flexible pavements, preferably under light and medium vehicular loadings. Construction of CBP at site is quick and easy in quality control. Usually, flexible pavement design philosophy is followed in CBP construction, though it is structurally different in terms of small block elements with high strength concrete and their interlocking aspects, frequent joints and discontinuity, restrained edge etc. Analytical solution for such group action of concrete blocks under loading in a three dimensional multilayer structure is complex and thus, the need of conducting experimental studies is necessitated for extensive understanding of the load—deformation characteristics and behavior of concrete blocks in pavement. The present paper focuses on the experimental studies for load transfer characteristics of CBP under different interlocking and supporting conditions. It is observed that both interlocking and supporting conditions affect significantly on the load transfer behavior in CBP structures. Coro-lock block exhibits better performance in terms of load carrying capacity and distortion behavior under static loads. Plate load tests are performed over subgrade, granular sub-base (GSB), CBP with and without GSB using different block shapes. For an example case, the comparison of CBP with conventional flexible pavement section is also presented and it is found that CBP provides considerable benefit in terms of construction cost of the road structure.

  2. Block matrix based LU decomposition to analyze kinetic damping in active plasma resonance spectroscopy

    NASA Astrophysics Data System (ADS)

    Roehl, Jan Hendrik; Oberrath, Jens

    2016-09-01

    ``Active plasma resonance spectroscopy'' (APRS) is a widely used diagnostic method to measure plasma parameter like electron density. Measurements with APRS probes in plasmas of a few Pa typically show a broadening of the spectrum due to kinetic effects. To analyze the broadening a general kinetic model in electrostatic approximation based on functional analytic methods has been presented [ 1 ] . One of the main results is, that the system response function Y(ω) is given in terms of the matrix elements of the resolvent of the dynamic operator evaluated for values on the imaginary axis. To determine the response function of a specific probe the resolvent has to be approximated by a huge matrix which is given by a banded block structure. Due to this structure a block based LU decomposition can be implemented. It leads to a solution of Y(ω) which is given only by products of matrices of the inner block size. This LU decomposition allows to analyze the influence of kinetic effects on the broadening and saves memory and calculation time. Gratitude is expressed to the internal funding of Leuphana University.

  3. Composition of clusters and building blocks in amylopectins from maize mutants deficient in starch synthase III.

    PubMed

    Zhu, Fan; Bertoft, Eric; Seetharaman, Koushik

    2013-12-18

    Branches in amylopectin are distributed along the backbone. Units of the branches are building blocks (smaller) and clusters (larger) based on the distance between branches. In this study, composition of clusters and building blocks of amylopectins from dull1 maize mutants deficient in starch synthase III (SSIII) with a common genetic background (W64A) were characterized and compared with the wild type. Clusters were produced from amylopectins by partial hydrolysis using α-amylase of Bacillus amyloliquefaciens and were subsequently treated with phosphorylase a and β-amylase to produce φ,β-limit dextrins. Clusters were further extensively hydrolyzed with the α-amylase to produce building blocks. Structures of clusters and building blocks were analyzed by diverse chromatographic techniques. The results showed that the dull1 mutation resulted in larger clusters with more singly branched building blocks. The average cluster contained ~5.4 blocks in dull1 mutants and ~4.2 blocks in the wild type. The results are compared with previous results from SSIII-deficient amo1 barley and suggest fundamental differences in the cluster structures.

  4. Bifunctional Organic Polymeric Catalysts with a Tunable Acid-Base Distance and Framework Flexibility

    PubMed Central

    Chen, Huanhui; Wang, Yanan; Wang, Qunlong; Li, Junhui; Yang, Shiqi; Zhu, Zhirong

    2014-01-01

    Acid-base bifunctional organic polymeric catalysts were synthesized with tunable structures. we demonstrated two synthesis approaches for structural fine-tune. In the first case, the framework flexibility was tuned by changing the ratio of rigid blocks to flexible blocks within the polymer framework. In the second case, we precisely adjusted the acid-base distance by distributing basic monomers to be adjacent to acidic monomers, and by changing the chain length of acidic monomers. In a standard test reaction for the aldol condensation of 4-nitrobenzaldehyde with acetone, the catalysts showed good reusability upon recycling and maintained relatively high conversion percentage. PMID:25267260

  5. A rate-constrained fast full-search algorithm based on block sum pyramid.

    PubMed

    Song, Byung Cheol; Chun, Kang-Wook; Ra, Jong Beom

    2005-03-01

    This paper presents a fast full-search algorithm (FSA) for rate-constrained motion estimation. The proposed algorithm, which is based on the block sum pyramid frame structure, successively eliminates unnecessary search positions according to rate-constrained criterion. This algorithm provides the identical estimation performance to a conventional FSA having rate constraint, while achieving considerable reduction in computation.

  6. Oligomers and Polymers Based on Pentacene Building Blocks

    PubMed Central

    Lehnherr, Dan; Tykwinski, Rik R.

    2010-01-01

    Functionalized pentacene derivatives continue to provide unique materials for organic semiconductor applications. Although oligomers and polymers based on pentacene building blocks remain quite rare, recent synthetic achievements have provided a number of examples with varied structural motifs. This review highlights recent work in this area and, when possible, contrasts the properties of defined-length pentacene oligomers to those of mono- and polymeric systems.

  7. Channel Estimation and Pilot Design for Massive MIMO Systems with Block-Structured Compressive Sensing

    NASA Astrophysics Data System (ADS)

    Lv, ZhuoKai; Yang, Tiejun; Zhu, Chunhua

    2018-03-01

    Through utilizing the technology of compressive sensing (CS), the channel estimation methods can achieve the purpose of reducing pilots and improving spectrum efficiency. The channel estimation and pilot design scheme are explored during the correspondence under the help of block-structured CS in massive MIMO systems. The block coherence property of the aggregate system matrix can be minimized so that the pilot design scheme based on stochastic search is proposed. Moreover, the block sparsity adaptive matching pursuit (BSAMP) algorithm under the common sparsity model is proposed so that the channel estimation can be caught precisely. Simulation results are to be proved the proposed design algorithm with superimposed pilots design and the BSAMP algorithm can provide better channel estimation than existing methods.

  8. Design and implementation of a proficiency-based, structured endoscopy course for medical students applying for a surgical specialty

    PubMed Central

    De Win, Gunter; Van Bruwaene, Siska; Allen, Christopher; De Ridder, Dirk

    2013-01-01

    Background Surgical simulation is becoming increasingly important in surgical education. Despite the important work done on simulators, simulator model development, and simulator assessment methodologies, there is a need for development of integrated simulators in the curriculum. In this paper, we describe the design of our evidence-based preclinical training program for medical students applying for a surgical career at the Centre for Surgical Technologies. Methods Twenty-two students participated in this training program. During their final months as medical students, they received structured, proficiency-based endoscopy training. The total amount of mentored training was 18 hours and the training was organized into three training blocks. The first block focused on psychomotor training, the second block focused on laparoscopic stitching and suturing, and the third block on laparoscopic dissection techniques and hemostasis. Deliberate practice was allowed and students had to show proficiency before proceeding to the next training block. Students’ psychomotor abilities were tested before the course and after each training block. At the beginning of their careers as surgical registrars, their performance on a laparoscopic suturing task was compared with that of registrars from the previous year who did not have this training course. Student opinions about this course were evaluated using a visual analog scale. Results All students rated the training course as useful and their psychomotor abilities improved markedly. All students performed deliberate practice, and those who participated in this course scored significantly (P < 0.0001) better on the laparoscopic suturing task than first year registrars who did not participate in this course. Conclusion Organization of a structured preclinical training program in laparoscopy for final year medical students is feasible, attractive, and successful. PMID:23901308

  9. Encoders for block-circulant LDPC codes

    NASA Technical Reports Server (NTRS)

    Andrews, Kenneth; Dolinar, Sam; Thorpe, Jeremy

    2005-01-01

    In this paper, we present two encoding methods for block-circulant LDPC codes. The first is an iterative encoding method based on the erasure decoding algorithm, and the computations required are well organized due to the block-circulant structure of the parity check matrix. The second method uses block-circulant generator matrices, and the encoders are very similar to those for recursive convolutional codes. Some encoders of the second type have been implemented in a small Field Programmable Gate Array (FPGA) and operate at 100 Msymbols/second.

  10. Superalloy Lattice Block Developed for Use in Lightweight, High-Temperature Structures

    NASA Technical Reports Server (NTRS)

    Hebsur, Mohan G.; Whittenberger, J. Daniel; Krause, David L.

    2003-01-01

    Successful development of advanced gas turbine engines for aircraft will require lightweight, high-temperature components. Currently titanium-aluminum- (TiAl) based alloys are envisioned for such applications because of their lower density (4 g/cm3) in comparison to superalloys (8.5 g/cm3), which have been utilized for hot turbine engine parts for over 50 years. However, a recently developed concept (lattice block) by JAMCORP, Inc., of Willmington, Massachusetts, would allow lightweight, high-temperature structures to be directly fabricated from superalloys and, thus, take advantage of their well-known, characterized properties. In its simplest state, lattice block is composed of thin ligaments arranged in a three dimensional triangulated trusslike configuration that forms a structurally rigid panel. Because lattice block can be fabricated by casting, correctly sized hardware is produced with little or no machining; thus very low cost manufacturing is possible. Together, the NASA Glenn Research Center and JAMCORP have extended their lattice block methodology for lower melting materials, such as Al alloys, to demonstrate that investment casting of superalloy lattice block is possible. This effort required advances in lattice block pattern design and assembly, higher temperature mold materials and mold fabrication technology, and foundry practice suitable for superalloys (ref. 1). Lattice block panels have been cast from two different Ni-base superalloys: IN 718, which is the most commonly utilized superalloy and retains its strength up to 650 C; and MAR M247, which possesses excellent mechanical properties to at least 1100 C. In addition to the open-cell lattice block geometry, same-sized lattice block panels containing a thin (1-mm-thick) solid face on one side have also been cast from both superalloys. The elevated-temperature mechanical properties of the open cell and face-sheeted superalloy lattice block panels are currently being examined, and the microstructure is being characterized in terms of casting defects. In addition, a small study (ref. 3) is being undertaken with GE Aircraft Engines to determine the suitability of superalloy lattice block for engine components.

  11. Structure to function: Spider silk and human collagen

    NASA Astrophysics Data System (ADS)

    Rabotyagova, Olena S.

    Nature has the ability to assemble a variety of simple molecules into complex functional structures with diverse properties. Collagens, silks and muscles fibers are some examples of fibrous proteins with self-assembling properties. One of the great challenges facing Science is to mimic these designs in Nature to find a way to construct molecules that are capable of organizing into functional supra-structures by self-assembly. In order to do so, a construction kit consisting of molecular building blocks along with a complete understanding on how to form functional materials is required. In this current research, the focus is on spider silk and collagen as fibrous protein-based biopolymers that can shed light on how to generate nanostructures through the complex process of self-assembly. Spider silk in fiber form offers a unique combination of high elasticity, toughness, and mechanical strength, along with biological compatibility and biodegrability. Spider silk is an example of a natural block copolymer, in which hydrophobic and hydrophilic blocks are linked together generating polymers that organize into functional materials with extraordinary properties. Since silks resemble synthetic block copolymer systems, we adopted the principles of block copolymer design from the synthetic polymer literature to build block copolymers based on spider silk sequences. Moreover, we consider spider silk to be an important model with which to study the relationships between structure and properties in our system. Thus, the first part of this work was dedicated to a novel family of spider silk block copolymers, where we generated a new family of functional spider silk-like block copolymers through recombinant DNA technology. To provide fundamental insight into relationships between peptide primary sequence, block composition, and block length and observed morphological and structural features, we used these bioengineered spider silk block copolymers to study secondary structure, morphological features and assembly. Aside from fundamental perspectives, we anticipate that these results will provide a blueprint for the design of precise materials for a range of potential applications such as controlled release devices, functional coatings, components of tissue regeneration materials and environmentally friendly polymers in future studies. In the second part of this work, human collagen type I was studied as another representative of the family of fibrous proteins. Collagen type I is the most abundant extracellular matrix protein in the human body, providing the basis for tissue structure and directing cellular functions. Collagen has a complex structural hierarchy, organized at different length scales, including the characteristic triple helical feature. In the present study we assessed the relationship between collagen structure (native vs. denatured) and sensitivity to UV radiation with a focus on changes in the primary structure, conformation, microstructure and material properties. Free radical reactions are involved in collagen degradation and a mechanism for UV-induced collagen degradation related to structure was proposed. The results from this study demonstrated the role of collagen supramolecular organization (triple helix) in the context of the effects of electromagnetic radiation on extracellular matrices. Owing to the fact that both silks and collagens are proteins that have found widespread interest for biomaterial related needs, we anticipate that the current studies will serve as a foundation for future biomaterial designs with controlled properties. Furthermore, fundamental insight into self-assembly and environmentally-2mediated degradation, will build a foundation for fundamental understanding of the remodeling and functions of these types of fibrous proteins in vivo and in vitro. This type of insight is essential for many areas of scientific inquiry, from drug delivery, to scaffolds for tissue engineering, and to the stability of materials in space.

  12. Measuring the change in hydration of a polypeptide-based block polymer vesicle as a function of pH

    NASA Astrophysics Data System (ADS)

    Smith, Ian; Charlier, Alban; Shishlov, Alexander; Savin, Daniel

    Amphiphilic AB2 star polymers undergo directed self-assembly into vesicles in aqueous solution. The overall structure of the assembly is responsive to a change in solution pH by incorporating an ionizable polypeptide as the A-block and two lipid-like tails for the B-blocks. Herein, we present some recent results in the solution characterization of polyglutamate-octadecanethiol2 (PE-DDT2) star polymers using static and dynamic light scattering, as well as transmission electron microscopy. An increase in pH will induce a transition in secondary structure of the PE block from an α-helix to an extended coil, thereby perturbing the morphological structure and resulting in an expansion of the vesicle. The magnitude of this response is much larger than what is expected based on the conformational transition of the peptide. The mechanism of this process can be probed by measuring the change in hydration at the surface of the hydrophobic bilayer. Towards this end, we utilize 2,4,6-trichloro-1,3,5-triazine (TCT) as a modular linker to install spin labels into the assembly as a mechanism to directly interrogate local hydrophobicity using electron paramagnetic resonance (EPR). NSF 1539347.

  13. Protograph LDPC Codes Over Burst Erasure Channels

    NASA Technical Reports Server (NTRS)

    Divsalar, Dariush; Dolinar, Sam; Jones, Christopher

    2006-01-01

    In this paper we design high rate protograph based LDPC codes suitable for binary erasure channels. To simplify the encoder and decoder implementation for high data rate transmission, the structure of codes are based on protographs and circulants. These LDPC codes can improve data link and network layer protocols in support of communication networks. Two classes of codes were designed. One class is designed for large block sizes with an iterative decoding threshold that approaches capacity of binary erasure channels. The other class is designed for short block sizes based on maximizing minimum stopping set size. For high code rates and short blocks the second class outperforms the first class.

  14. Efficiency improvement of green light-emitting diodes by employing all-quaternary active region and electron-blocking layer

    NASA Astrophysics Data System (ADS)

    Usman, Muhammad; Saba, Kiran; Han, Dong-Pyo; Muhammad, Nazeer

    2018-01-01

    High efficiency of green GaAlInN-based light-emitting diode (LED) has been proposed with peak emission wavelength of ∼510 nm. By introducing quaternary quantum well (QW) along with the quaternary barrier (QB) and quaternary electron blocking layer (EBL) in a single structure, an efficiency droop reduction of up to 29% has been achieved in comparison to the conventional GaN-based LED. The proposed structure has significantly reduced electrostatic field in the active region. As a result, carrier leakage has been minimized and spontaneous emission rate has been doubled.

  15. A new routing enhancement scheme based on node blocking state advertisement in wavelength-routed WDM networks

    NASA Astrophysics Data System (ADS)

    Hu, Peigang; Jin, Yaohui; Zhang, Chunlei; He, Hao; Hu, WeiSheng

    2005-02-01

    The increasing switching capacity brings the optical node with considerable complexity. Due to the limitation in cost and technology, an optical node is often designed with partial switching capability and partial resource sharing. It means that the node is of blocking to some extent, for example multi-granularity switching node, which in fact is a structure using pass wavelength to reduce the dimension of OXC, and partial sharing wavelength converter (WC) OXC. It is conceivable that these blocking nodes will have great effects on the problem of routing and wavelength assignment. Some previous works studied the blocking case, partial WC OXC, using complicated wavelength assignment algorithm. But the complexities of these schemes decide them to be not in practice in real networks. In this paper, we propose a new scheme based on the node blocking state advertisement to reduce the retry or rerouting probability and improve the efficiency of routing in the networks with blocking nodes. In the scheme, node blocking state are advertised to the other nodes in networks, which will be used for subsequent route calculation to find a path with lowest blocking probability. The performance of the scheme is evaluated using discrete event model in 14-node NSFNET, all the nodes of which employ a kind of partial sharing WC OXC structure. In the simulation, a simple First-Fit wavelength assignment algorithm is used. The simulation results demonstrate that the new scheme considerably reduces the retry or rerouting probability in routing process.

  16. Ring system-based chemical graph generation for de novo molecular design

    NASA Astrophysics Data System (ADS)

    Miyao, Tomoyuki; Kaneko, Hiromasa; Funatsu, Kimito

    2016-05-01

    Generating chemical graphs in silico by combining building blocks is important and fundamental in virtual combinatorial chemistry. A premise in this area is that generated structures should be irredundant as well as exhaustive. In this study, we develop structure generation algorithms regarding combining ring systems as well as atom fragments. The proposed algorithms consist of three parts. First, chemical structures are generated through a canonical construction path. During structure generation, ring systems can be treated as reduced graphs having fewer vertices than those in the original ones. Second, diversified structures are generated by a simple rule-based generation algorithm. Third, the number of structures to be generated can be estimated with adequate accuracy without actual exhaustive generation. The proposed algorithms were implemented in structure generator Molgilla. As a practical application, Molgilla generated chemical structures mimicking rosiglitazone in terms of a two dimensional pharmacophore pattern. The strength of the algorithms lies in simplicity and flexibility. Therefore, they may be applied to various computer programs regarding structure generation by combining building blocks.

  17. Durability of Bricks Coated with Red mud Based Geopolymer Paste

    NASA Astrophysics Data System (ADS)

    Singh, Smita; Basavanagowda, S. N.; Aswath, M. U.; Ranganath, R. V.

    2016-09-01

    The present study is undertaken to assess the durability of concrete blocks coated with red mud - fly ash based geopolymer paste. Concrete blocks of size 200 x 200 x 100mm were coated with geopolymer paste synthesized by varying the percentages of red mud and fly ash. Uncoated concrete blocks were also tested for the durability for comparison. In thermal resistance test, the blocks were subjected to 600°C for an hour whereas in acid resistance test, they were kept in 5% sulphuric acid solution for 4 weeks. The specimens were thereafter studied for surface degradation, strength loss and weight loss. Pastes with red mud percentage greater than 50% developed lot of shrinkage cracks. The blocks coated with 30% and 50% red mud paste showed better durability than the other blocks. The use of blocks coated with red mud - fly ash geopolymer paste improves the aesthetics, eliminates the use of plaster and improves the durability of the structure.

  18. Optimal Hydrophobicity in Ring-Opening Metathesis Polymerization-Based Protein Mimics Required for siRNA Internalization.

    PubMed

    deRonde, Brittany M; Posey, Nicholas D; Otter, Ronja; Caffrey, Leah M; Minter, Lisa M; Tew, Gregory N

    2016-06-13

    Exploring the role of polymer structure for the internalization of biologically relevant cargo, specifically siRNA, is of critical importance to the development of improved delivery reagents. Herein, we report guanidinium-rich protein transduction domain mimics (PTDMs) based on a ring-opening metathesis polymerization scaffold containing tunable hydrophobic moieties that promote siRNA internalization. Structure-activity relationships using Jurkat T cells and HeLa cells were explored to determine how the length of the hydrophobic block and the hydrophobic side chain compositions of these PTDMs impacted siRNA internalization. To explore the hydrophobic block length, two different series of diblock copolymers were synthesized: one series with symmetric block lengths and one with asymmetric block lengths. At similar cationic block lengths, asymmetric and symmetric PTDMs promoted siRNA internalization in the same percentages of the cell population regardless of the hydrophobic block length; however, with 20 repeat units of cationic charge, the asymmetric block length had greater siRNA internalization, highlighting the nontrivial relationships between hydrophobicity and overall cationic charge. To further probe how the hydrophobic side chains impacted siRNA internalization, an additional series of asymmetric PTDMs was synthesized that featured a fixed hydrophobic block length of five repeat units that contained either dimethyl (dMe), methyl phenyl (MePh), or diphenyl (dPh) side chains and varied cationic block lengths. This series was further expanded to incorporate hydrophobic blocks consisting of diethyl (dEt), diisobutyl (diBu), and dicyclohexyl (dCy) based repeat units to better define the hydrophobic window for which our PTDMs had optimal activity. High-performance liquid chromatography retention times quantified the relative hydrophobicities of the noncationic building blocks. PTDMs containing the MePh, diBu, and dPh hydrophobic blocks were shown to have superior siRNA internalization capabilities compared to their more and less hydrophobic counterparts, demonstrating a critical window of relative hydrophobicity for optimal internalization. This better understanding of how hydrophobicity impacts PTDM-induced internalization efficiencies will help guide the development of future delivery reagents.

  19. Retrofit Audits and Cost Estimates. A Look at Quality and Consistency

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

    Eisenberg, L.; Shapiro, C.; Fleischer, W.

    Retrofit NYC Block by Block is an outreach program targeting owners of one- to four-family homes, the most common building type in New York City, with more than 600,000 structures citywide. Administered by the Pratt Center for Community Development and implemented by four nonprofit, community-based organizations, Block by Block connects residents, businesses, and religious and civic organizations in predominantly low-and moderate-income neighborhoods with one or more of a half-dozen public and private financial incentive programs that facilitate energy-efficiency retrofits. This research project sought to evaluate the approach, effectiveness, and the energy use reductions accomplished by the Retrofit NYC: Block bymore » Block program.« less

  20. Retrofit Audits and Cost Estimates: A Look at Quality and Consistency

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

    Eisenberg, L.; Shapiro, C.; Fleischer, W.

    Retrofit NYC Block by Block is an outreach program targeting owners of one- to four-family homes, the most common building type in New York City, with more than 600,000 structures citywide. Administered by the Pratt Center for Community Development and implemented by four nonprofit, community based organizations, Block by Block connects residents, businesses, and religious and civic organizations in predominantly low- and moderate-income neighborhoods with one or more of a half-dozen public and private financial incentive programs that facilitate energy-efficiency retrofits. This research project sought to evaluate the approach, effectiveness, and the energy use reductions accomplished by the Retrofit NYC:more » Block by Block program.« less

  1. Propagation of eigenmodes and transfer functions in waveguide WDM structures

    NASA Astrophysics Data System (ADS)

    Mashkov, Vladimir A.; Francoeur, S.; Geuss, U.; Neiser, K.; Temkin, Henryk

    1998-02-01

    A method of propagation functions and transfer amplitudes suitable for the design of integrated optical circuits is presented. The method is based on vectorial formulation of electrodynamics: the distributions and propagation of electromagnetic fields in optical circuits is described by equivalent surface sources. This approach permits a division of complex optical waveguide structures into sets of primitive blocks and to separately calculate the transfer function and the transfer amplitude for each block. The transfer amplitude of the entire optical system is represented by a convolution of transfer amplitudes of its primitive blocks. The eigenvalues and eigenfunctions of arbitrary waveguide structure are obtained in the WKB approximation and compared with other methods. The general approach is illustrated with the transfer amplitude calculations for Dragone's star coupler and router.

  2. A mixed molecular building block strategy for the design of nested polyhedron metal-organic frameworks.

    PubMed

    Tian, Dan; Chen, Qiang; Li, Yue; Zhang, Ying-Hui; Chang, Ze; Bu, Xian-He

    2014-01-13

    A mixed molecular building block (MBB) strategy for the synthesis of double-walled cage-based porous metal-organic frameworks (MOFs) is presented. By means of this method, two isostructural porous MOFs built from unprecedented double-walled metal-organic octahedron were obtained by introducing two size-matching C3 -symmetric molecular building blocks with different rigidities. With their unique framework structures, these MOFs provide, to the best of our knowledge, the first examples of double-walled octahedron-based MOFs. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Block copolymer libraries: modular versatility of the macromolecular Lego system.

    PubMed

    Lohmeijer, Bas G G; Wouters, Daan; Yin, Zhihui; Schubert, Ulrich S

    2004-12-21

    The synthesis and characterization of a new 4 x 4 library of block copolymers based on polystyrene and poly(ethylene oxide) connected by an asymmetrical octahedral bis(terpyridine) ruthenium complex at the block junction are described, while initial studies on the thin film morphology of the components of the library are presented by the use of Atomic Force Microscopy, demonstrating the impact of a library approach to derive structure-property relationships.

  4. [Construction of haplotype and haplotype block based on tag single nucleotide polymorphisms and their applications in association studies].

    PubMed

    Gu, Ming-liang; Chu, Jia-you

    2007-12-01

    Human genome has structures of haplotype and haplotype block which provide valuable information on human evolutionary history and may lead to the development of more efficient strategies to identify genetic variants that increase susceptibility to complex diseases. Haplotype block can be divided into discrete blocks of limited haplotype diversity. In each block, a small fraction of ptag SNPsq can be used to distinguish a large fraction of the haplotypes. These tag SNPs can be potentially useful for construction of haplotype and haplotype block, and association studies in complex diseases. There are two general classes of methods to construct haplotype and haplotype blocks based on genotypes on large pedigrees and statistical algorithms respectively. The author evaluate several construction methods to assess the power of different association tests with a variety of disease models and block-partitioning criteria. The advantages, limitations and applications of each method and the application in the association studies are discussed equitably. With the completion of the HapMap and development of statistical algorithms for addressing haplotype reconstruction, ideas of construction of haplotype based on combination of mathematics, physics, and computer science etc will have profound impacts on population genetics, location and cloning for susceptible genes in complex diseases, and related domain with life science etc.

  5. Block-diagonalization as a tool for the robust diabatization of high-dimensional potential energy surfaces

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

    Venghaus, Florian; Eisfeld, Wolfgang, E-mail: wolfgang.eisfeld@uni-bielefeld.de

    2016-03-21

    Robust diabatization techniques are key for the development of high-dimensional coupled potential energy surfaces (PESs) to be used in multi-state quantum dynamics simulations. In the present study we demonstrate that, besides the actual diabatization technique, common problems with the underlying electronic structure calculations can be the reason why a diabatization fails. After giving a short review of the theoretical background of diabatization, we propose a method based on the block-diagonalization to analyse the electronic structure data. This analysis tool can be used in three different ways: First, it allows to detect issues with the ab initio reference data and ismore » used to optimize the setup of the electronic structure calculations. Second, the data from the block-diagonalization are utilized for the development of optimal parametrized diabatic model matrices by identifying the most significant couplings. Third, the block-diagonalization data are used to fit the parameters of the diabatic model, which yields an optimal initial guess for the non-linear fitting required by standard or more advanced energy based diabatization methods. The new approach is demonstrated by the diabatization of 9 electronic states of the propargyl radical, yielding fully coupled full-dimensional (12D) PESs in closed form.« less

  6. Alternating block polyurethanes based on PCL and PEG as potential nerve regeneration materials.

    PubMed

    Li, Guangyao; Li, Dandan; Niu, Yuqing; He, Tao; Chen, Kevin C; Xu, Kaitian

    2014-03-01

    Polyurethanes with regular and controlled block arrangement, i.e., alternating block polyurethanes (abbreviated as PUCL-alt-PEG) based on poly(ε-caprolactone) (PCL-diol) and poly(ethylene glycol) (PEG) was prepared via selectively coupling reaction between PCL-diol and diisocyanate end-capped PEG. Chemical structure, molecular weight, distribution, and thermal properties were systematically characterized by FTIR, (1)H NMR, GPC, DSC, and TGA. Hydrophilicity was studied by static contact angle of H2O and CH2I2. Film surface was observed by scanning electron microscope (SEM) and atomic force microscopy, and mechanical properties were assessed by universal test machine. Results show that alternating block polyurethanes give higher crystal degree, higher mechanical properties, and more hydrophilic and rougher (deep ravine) surface than their random counterpart, due to regular and controlled structure. Platelet adhesion illustrated that PUCL-alt-PEG has better hemocompatibility and the hemacompatibility was affected significantly by PEG content. Excellent hemocompatibility was obtained with high PEG content. CCK-8 assay and SEM observation revealed much better cell compatibility of fibroblast L929 and rat glial cells on the alternating block polyurethanes than that on random counterpart. Alternating block polyurethane PUC20-a-E4 with optimized composition, mechanical, surface properties, hemacompatibility, and highest cell growth and proliferation was achieved for potential use in nerve regeneration. Copyright © 2013 Wiley Periodicals, Inc.

  7. Vision-Based UAV Flight Control and Obstacle Avoidance

    DTIC Science & Technology

    2006-01-01

    denoted it by Vb = (Vb1, Vb2 , Vb3). Fig. 2 shows the block diagram of the proposed vision-based motion analysis and obstacle avoidance system. We denote...structure analysis often involve computation- intensive computer vision tasks, such as feature extraction and geometric modeling. Computation-intensive...First, we extract a set of features from each block. 2) Second, we compute the distance between these two sets of features. In conventional motion

  8. Translatory shock absorber for attitude sensors

    NASA Technical Reports Server (NTRS)

    Vonpragenau, G. L.; Morgan, I. T., Jr.; Kirby, C. A. (Inventor)

    1976-01-01

    A translatory shock absorber is provided for mounting an attitude sensor thereon for isolating a sensor from translatory vibrations. The translatory shock absorber includes a hollow block structure formed as one piece to form a parallelogram. The absorber block structure includes a movable top plate for supporting the attitude sensor and a fixed base plate with opposed side plates interposed between. At the junctions of the side plates, and the base and top plates, there are provided grooves which act as flexible hinges for attenuating translatory vibrations. A damping material is supported on a pedestal which is carried on the base plate between the side plates thereof. The top of the damping material rests against the bottom surface of the top plate for eliminating the resonant peaks of vibration.

  9. Quasi-Block Copolymers Based on a General Polymeric Chain Stopper.

    PubMed

    Sanguramath, Rajashekharayya A; Nealey, Paul F; Shenhar, Roy

    2016-07-11

    Quasi-block copolymers (q-BCPs) are block copolymers consisting of conventional and supramolecular blocks, in which the conventional block is end-terminated by a functionality that interacts with the supramolecular monomer (a "chain stopper" functionality). A new design of q-BCPs based on a general polymeric chain stopper, which consists of polystyrene end-terminated with a sulfonate group (PS-SO3 Li), is described. Through viscosity measurements and a detailed diffusion-ordered NMR spectroscopy study, it is shown that PS-SO3 Li can effectively cap two types of model supramolecular monomers to form q-BCPs in solution. Furthermore, differential scanning calorimetry data and structural characterization of thin films by scanning force microscopy suggests the existence of the q-BCP architecture in the melt. The new design considerably simplifies the synthesis of polymeric chain stoppers; thus promoting the utilization of q-BCPs as smart, nanostructured materials. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Comparative evaluation of structured oil systems: Shellac oleogel, HPMC oleogel, and HIPE gel.

    PubMed

    Patel, Ashok R; Dewettinck, Koen

    2015-11-01

    In lipid-based food products, fat crystals are used as building blocks for creating a crystalline network that can trap liquid oil into a 3D gel-like structure which in turn is responsible for the desirable mouth feel and texture properties of the food products. However, the recent ban on the use of trans-fat in the US, coupled with the increasing concerns about the negative health effects of saturated fat consumption, has resulted in an increased interest in the area of identifying alternative ways of structuring edible oils using non-fat-based building blocks. In this paper, we give a brief account of three alternative approaches where oil structuring was carried out using wax crystals (shellac), polymer strands (hydrophilic cellulose derivative), and emulsion droplets as structurants. These building blocks resulted in three different types of oleogels that showed distinct rheological properties and temperature functionalities. The three approaches are compared in terms of the preparation process (ease of processing), properties of the formed systems (microstructure, rheological gel strength, temperature response, effect of water incorporation, and thixotropic recovery), functionality, and associated limitations of the structured systems. The comparative evaluation is made such that the new researchers starting their work in the area of oil structuring can use this discussion as a general guideline. Various aspects of oil binding for three different building blocks were studied in this work. The practical significance of this study includes (i) information on the preparation process and the concentrations of structuring agents required for efficient gelation and (ii) information on the behavior of oleogels to temperature, applied shear, and presence of water. This information can be very useful for selecting the type of structuring agents keeping the final applications in mind. For detailed information on the actual edible applications (bakery, chocolate, and spreads) which are based on the oleogel systems described in this manuscript, the readers are advised to refer our recent papers published elsewhere. (Food & Function 2014, 5, 645-652 and Food & Function 2014, 5, 2833-2841).

  11. Maximum volume cuboids for arbitrarily shaped in-situ rock blocks as determined by discontinuity analysis—A genetic algorithm approach

    NASA Astrophysics Data System (ADS)

    Ülker, Erkan; Turanboy, Alparslan

    2009-07-01

    The block stone industry is one of the main commercial use of rock. The economic potential of any block quarry depends on the recovery rate, which is defined as the total volume of useful rough blocks extractable from a fixed rock volume in relation to the total volume of moved material. The natural fracture system, the rock type(s) and the extraction method used directly influence the recovery rate. The major aims of this study are to establish a theoretical framework for optimising the extraction process in marble quarries for a given fracture system, and for predicting the recovery rate of the excavated blocks. We have developed a new approach by taking into consideration only the fracture structure for maximum block recovery in block quarries. The complete model uses a linear approach based on basic geometric features of discontinuities for 3D models, a tree structure (TS) for individual investigation and finally a genetic algorithm (GA) for the obtained cuboid volume(s). We tested our new model in a selected marble quarry in the town of İscehisar (AFYONKARAHİSAR—TURKEY).

  12. Efficient Multiplexer FPGA Block Structures Based on G4FETs

    NASA Technical Reports Server (NTRS)

    Vatan, Farrokh; Fijany, Amir

    2009-01-01

    Generic structures have been conceived for multiplexer blocks to be implemented in field-programmable gate arrays (FPGAs) based on four-gate field-effect transistors (G(sup 4)FETs). This concept is a contribution to the continuing development of digital logic circuits based on G4FETs and serves as a further demonstration that logic circuits based on G(sup 4)FETs could be more efficient (in the sense that they could contain fewer transistors), relative to functionally equivalent logic circuits based on conventional transistors. Results in this line of development at earlier stages were summarized in two previous NASA Tech Briefs articles: "G(sup 4)FETs as Universal and Programmable Logic Gates" (NPO-41698), Vol. 31, No. 7 (July 2007), page 44, and "Efficient G4FET-Based Logic Circuits" (NPO-44407), Vol. 32, No. 1 ( January 2008), page 38 . As described in the first-mentioned previous article, a G4FET can be made to function as a three-input NOT-majority gate, which has been shown to be a universal and programmable logic gate. The universality and programmability could be exploited to design logic circuits containing fewer components than are required for conventional transistor-based circuits performing the same logic functions. The second-mentioned previous article reported results of a comparative study of NOT-majority-gate (G(sup 4)FET)-based logic-circuit designs and equivalent NOR- and NAND-gate-based designs utilizing conventional transistors. [NOT gates (inverters) were also included, as needed, in both the G(sup 4)FET- and the NOR- and NAND-based designs.] In most of the cases studied, fewer logic gates (and, hence, fewer transistors), were required in the G(sup 4)FET-based designs. There are two popular categories of FPGA block structures or architectures: one based on multiplexers, the other based on lookup tables. In standard multiplexer- based architectures, the basic building block is a tree-like configuration of multiplexers, with possibly a few additional logic gates such as ANDs or ORs. Interconnections are realized by means of programmable switches that may connect the input terminals of a block to output terminals of other blocks, may bridge together some of the inputs, or may connect some of the input terminals to signal sources representing constant logical levels 0 or 1. The left part of the figure depicts a four-to-one G(sup 4)FET-based multiplexer tree; the right part of the figure depicts a functionally equivalent four-to-one multiplexer based on conventional transistors. The G(sup 4)FET version would contains 54 transistors; the conventional version contains 70 transistors.

  13. A 3D Analysis of Rock Block Deformation and Failure Mechanics Using Terrestrial Laser Scanning

    NASA Astrophysics Data System (ADS)

    Rowe, Emily; Hutchinson, D. Jean; Kromer, Ryan A.; Edwards, Tom

    2017-04-01

    Many natural geological hazards are present along the Thompson River corridor in British Columbia, Canada, including one particularly hazardous rocky slope known as the White Canyon. Railway tracks used by Canadian National (CN) and Canadian Pacific (CP) Railway companies pass through this area at the base of the Canyon slope. The geologically complex and weathered rock face exposed at White Canyon is prone to rockfalls. With a limited ditch capacity, these falling rocks have the potential to land on the tracks and therefore increase the risk of train derailment. Since 2012, terrestrial laser scanning (TLS) data has been collected at this site on a regular basis to enable researchers at Queen's University to study these rockfalls in greater detail. In this paper, the authors present a summary of an analysis of these TLS datasets including an examination of the pre-failure deformation patterns exhibited by failed rock blocks as well as an investigation into the influence of structural constraints on the pre-failure behavior of these blocks. Aligning rockfall source zones in an early point cloud dataset to a later dataset generates a transformation matrix describing the movement of the block from one scan to the next. This process was repeated such that the motion of the block over the entire TLS data coverage period was measured. A 3D roto-translation algorithm was then used to resolve the motion into translation and rotation components (Oppikofer et al. 2009; Kromer et al. 2015). Structural information was plotted on a stereonet for further analysis. A total of 111 rockfall events exceeding a volume of 1 m3 were analyzed using this approach. The study reveals that although some rockfall source blocks blocks do not exhibit detectable levels of deformation prior to failure, others do experience cm-level translation and rotation on the order of 1 to 6 degrees before detaching from the slope. Moreover, these movements may, in some cases, be related to the discontinuity planes on the slope that were confining the block. It is concluded that rock blocks in White Canyon may be classified as one of five main failure mechanisms based on their pre-failure deformation and structure: planar slide, topple, rotation, wedge, and overhang, with overhang failures representing a large portion of rockfalls in this area. Overhang rockfalls in the White Canyon are characterized by blocks that (a) are not supported by an underlying discontinuity plane, and (b) generally do not exhibit pre-failure deformation. Though overhanging rock blocks are a structural subset of toppling failure, their behavior suggests a different mechanism of detachment. Future work will further populate the present database of rockfalls in White Canyon and will expand the study to include other sites along this corridor. The ultimate goal of this research is to establish warning thresholds based on deformation magnitudes for rockfalls in White Canyon to assist Canadian railways in better understanding and managing these slopes.

  14. Observing atmospheric blocking with GPS radio occultation - one decade of measurements

    NASA Astrophysics Data System (ADS)

    Brunner, Lukas; Steiner, Andrea

    2017-04-01

    Atmospheric blocking has received a lot of attention in recent years due to its impact on mid-latitude circulation and subsequently on weather extremes such as cold and warm spells. So far blocking studies have been based mainly on re-analysis data or model output. However, it has been shown that blocking frequency exhibits considerable inter-model spread in current climate models. Here we use one decade (2006 to 2016) of satellite-based observations from GPS radio occultation (RO) to analyze blocking in RO data building on work by Brunner et al. (2016). Daily fields on a 2.5°×2.5° longitude-latitude grid are calculated by applying an adequate gridding strategy to the RO measurements. For blocking detection we use a standard blocking detection algorithm based on 500 hPa geopotential height (GPH) gradients. We investigate vertically resolved atmospheric variables such as GPH, temperature, and water vapor before, during, and after blocking events to increase process understanding. Moreover, utilizing the coverage of the RO data set, we investigate global blocking frequencies. The main blocking regions in the northern and southern hemisphere are identified and the (vertical) atmospheric structure linked to blocking events is compared. Finally, an inter-comparison of results from RO data to different re-analyses, such as ERA-Interim, MERRA 2, and JRA-55, is presented. Brunner, L., A. K. Steiner, B. Scherllin-Pirscher, and M. W. Jury (2016): Exploring atmospheric blocking with GPS radio occultation observations. Atmos. Chem. Phys., 16, 4593-4604, doi:10.5194/acp-16-4593-2016.

  15. Reduction of shunt current in buffer-free IrMn based spin-valve structures

    NASA Astrophysics Data System (ADS)

    Kocaman, B.; Akdoğan, N.

    2018-06-01

    The presence of thick buffer layers in magnetic sensor devices decreases sensor sensitivity due to shunt currents. With this motivation, we produced IrMn-based spin-valve multilayers without using buffer layer. We also studied the effects of post-annealing and IrMn thickness on exchange bias field (HEB) and blocking temperature (TB) of the system. Magnetization measurements indicate that both HEB and TB values are significantly enhanced with post-annealing of IrMn layer. In addition, we report that IrMn thickness of the system strongly influences the magnetization and transport characteristics of the spin-valve structures. We found that the minimum thickness of IrMn layer is 6 nm in order to achieve the lowest shunt current and high blocking temperature (>300 K). We also investigated the training of exchange bias to check the long-term durability of IrMn-based spin-valve structures for device applications.

  16. Strategy to Achieve Highly Porous/Biocompatible Macroscale Cell Blocks, Using a Collagen/Genipin-bioink and an Optimal 3D Printing Process.

    PubMed

    Kim, Yong Bok; Lee, Hyeongjin; Kim, Geun Hyung

    2016-11-30

    Recently, a three-dimensional (3D) bioprinting process for obtaining a cell-laden structure has been widely applied because of its ability to fabricate biomimetic complex structures embedded with and without cells. To successfully obtain a cell-laden porous block, the cell-delivering vehicle, bioink, is one of the significant factors. Until now, various biocompatible hydrogels (synthetic and natural biopolymers) have been utilized in the cell-printing process, but a bioink satisfying both biocompatibility and print-ability requirements to achieve a porous structure with reasonable mechanical strength has not been issued. Here, we propose a printing strategy with optimal conditions including a safe cross-linking procedure for obtaining a 3D porous cell block composed of a biocompatible collagen-bioink and genipin, a cross-linking agent. To obtain the optimal processing conditions, we modified the 3D printing machine and selected an optimal cross-linking condition (∼1 mM and 1 h) of genipin solution. To show the feasibility of the process, 3D pore-interconnected cell-laden constructs were manufactured using osteoblast-like cells (MG63) and human adipose stem cells (hASCs). Under these processing conditions, a macroscale 3D collagen-based cell block of 21 × 21 × 12 mm 3 and over 95% cell viability was obtained. In vitro biological testing of the cell-laden 3D porous structure showed that the embedded cells were sufficiently viable, and their proliferation was significantly higher; the cells also exhibited increased osteogenic activities compared to the conventional alginate-based bioink (control). The results indicated the fabrication process using the collagen-bioink would be an innovative platform to design highly biocompatible and mechanically stable cell blocks.

  17. Geometrical appearance and spatial arrangement of structural blocks of the Malan loess in NW China: implications for the formation of loess columns

    NASA Astrophysics Data System (ADS)

    Li, Yanrong; Zhang, Tao; Zhang, Yongbo; Xu, Qiang

    2018-06-01

    Loess, as one of the main Quaternary deposits, covers approximately 6% of the land surface of the Earth. Although loess is loose and fragile, loess columns are popular and they can stand stably for hundreds of years, thereby forming a spectacular landform. The formation of such special column-shaped soil structures is puzzling, and the underlying fundamentals remain unclear. The present study focuses on quantifying and examining the geometrical shape and spatial alignment of structural blocks of the Malan loess at different locations in the Loess Plateau of China. The structural blocks under investigation include clay- and silt-sized particles, aggregates, fragments, lumps, and columns, which vary in size from microns to tens of meters. Regardless of their size, the structural blocks of the Malan loess are found to be similar in shape, i.e., elongated with a length-to-width ratio of approximately 2.6. The aggregates, fragments, lumps, columns, and macropores between aggregates exhibit strong concentration in the vertical or subvertical alignment. These phenomena imply that the Malan loess is anisotropic and it is composed of a combination of vertically aligned strong units and vertically aligned weak segments. Based on this, "vertiloess" structure is proposed to denote this combination. The vertiloess structure prevents horizontal erosion, but favors spalling, peeling, toppling, falling and cracking-sliding of vertical loess pieces, thereby forming loess columns.

  18. Self-Assembly and Responsiveness of Polypeptide-Based Star and Triblock Copolymers

    NASA Astrophysics Data System (ADS)

    Savin, Daniel

    This study involves the bottom-up design and tunability of responsive, peptide-based block polymers. The self-assembly of amphiphilic block polymers is dictated primarily by the balance between the hydrophobic core volume and the hydrophilic corona. In these studies, amphiphilic triblock and star copolymers containing poly(lysine) (PK), poly(leucine) (PL) and poly(glutamic acid) (PE) were synthesized and their solution properties studied using dynamic light scattering, circular dichroism spectroscopy and transmission electron microscopy. The peptide block in these structures can serve to introduce pH responsiveness (in the case of PK and PE), or can facilitate the formation of elongated or kinetically-trapped structures (in the case of PL.) This talk will present some recent studies in solution morphology transitions that occur in these materials under varying solution conditions. As the topological complexity of the polymers increases from diblock to linear triblock or star polymers, the solution morphology and response becomes much more complex. We present a systematic series of structures, with increasing complexity, that have applications as passive and active delivery vehicles, hydrogels, and responsive viscosity modifiers. NSF CHE-1539347.

  19. Tandem Repeat Proteins Inspired By Squid Ring Teeth

    NASA Astrophysics Data System (ADS)

    Pena-Francesch, Abdon

    Proteins are large biomolecules consisting of long chains of amino acids that hierarchically assemble into complex structures, and provide a variety of building blocks for biological materials. The repetition of structural building blocks is a natural evolutionary strategy for increasing the complexity and stability of protein structures. However, the relationship between amino acid sequence, structure, and material properties of protein systems remains unclear due to the lack of control over the protein sequence and the intricacies of the assembly process. In order to investigate the repetition of protein building blocks, a recently discovered protein from squids is examined as an ideal protein system. Squid ring teeth are predatory appendages located inside the suction cups that provide a strong grasp of prey, and are solely composed of a group of proteins with tandem repetition of building blocks. The objective of this thesis is the understanding of sequence, structure and property relationship in repetitive protein materials inspired in squid ring teeth for the first time. Specifically, this work focuses on squid-inspired structural proteins with tandem repeat units in their sequence (i.e., repetition of alternating building blocks) that are physically cross-linked via beta-sheet structures. The research work presented here tests the hypothesis that, in these systems, increasing the number of building blocks in the polypeptide chain decreases the protein network defects and improves the material properties. Hence, the sequence, nanostructure, and properties (thermal, mechanical, and conducting) of tandem repeat squid-inspired protein materials are examined. Spectroscopic structural analysis, advanced materials characterization, and entropic elasticity theory are combined to elucidate the structure and material properties of these repetitive proteins. This approach is applied not only to native squid proteins but also to squid-inspired synthetic polypeptides that allow for a fine control of the sequence and network morphology. The results provided in this work establish a clear dependence between the repetitive building blocks, the network morphology, and the properties of squid-inspired repetitive protein materials. Increasing the number of tandem repeat units in SRT-inspired proteins led to more effective protein networks with superior properties. Through increasing tandem repetition and optimization of network morphology, highly efficient protein materials capable of withstanding deformations up to 400% of their original length, with MPa-GPa modulus, high energy absorption (50 MJ m-3), peak proton conductivity of 3.7 mS cm-1 (at pH 7, highest reported to date for biological materials), and peak thermal conductivity of 1.4 W m-1 K -1 (which exceeds that of most polymer materials) were developed. These findings introduce new design rules in the engineering of proteins based on tandem repetition and morphology control, and provide a novel framework for tailoring and optimizing the properties of protein-based materials.

  20. Trellises and Trellis-Based Decoding Algorithms for Linear Block Codes

    NASA Technical Reports Server (NTRS)

    Lin, Shu

    1998-01-01

    A code trellis is a graphical representation of a code, block or convolutional, in which every path represents a codeword (or a code sequence for a convolutional code). This representation makes it possible to implement Maximum Likelihood Decoding (MLD) of a code with reduced decoding complexity. The most well known trellis-based MLD algorithm is the Viterbi algorithm. The trellis representation was first introduced and used for convolutional codes [23]. This representation, together with the Viterbi decoding algorithm, has resulted in a wide range of applications of convolutional codes for error control in digital communications over the last two decades. There are two major reasons for this inactive period of research in this area. First, most coding theorists at that time believed that block codes did not have simple trellis structure like convolutional codes and maximum likelihood decoding of linear block codes using the Viterbi algorithm was practically impossible, except for very short block codes. Second, since almost all of the linear block codes are constructed algebraically or based on finite geometries, it was the belief of many coding theorists that algebraic decoding was the only way to decode these codes. These two reasons seriously hindered the development of efficient soft-decision decoding methods for linear block codes and their applications to error control in digital communications. This led to a general belief that block codes are inferior to convolutional codes and hence, that they were not useful. Chapter 2 gives a brief review of linear block codes. The goal is to provide the essential background material for the development of trellis structure and trellis-based decoding algorithms for linear block codes in the later chapters. Chapters 3 through 6 present the fundamental concepts, finite-state machine model, state space formulation, basic structural properties, state labeling, construction procedures, complexity, minimality, and sectionalization of trellises. Chapter 7 discusses trellis decomposition and subtrellises for low-weight codewords. Chapter 8 first presents well known methods for constructing long powerful codes from short component codes or component codes of smaller dimensions, and then provides methods for constructing their trellises which include Shannon and Cartesian product techniques. Chapter 9 deals with convolutional codes, puncturing, zero-tail termination and tail-biting.Chapters 10 through 13 present various trellis-based decoding algorithms, old and new. Chapter 10 first discusses the application of the well known Viterbi decoding algorithm to linear block codes, optimum sectionalization of a code trellis to minimize computation complexity, and design issues for IC (integrated circuit) implementation of a Viterbi decoder. Then it presents a new decoding algorithm for convolutional codes, named Differential Trellis Decoding (DTD) algorithm. Chapter 12 presents a suboptimum reliability-based iterative decoding algorithm with a low-weight trellis search for the most likely codeword. This decoding algorithm provides a good trade-off between error performance and decoding complexity. All the decoding algorithms presented in Chapters 10 through 12 are devised to minimize word error probability. Chapter 13 presents decoding algorithms that minimize bit error probability and provide the corresponding soft (reliability) information at the output of the decoder. Decoding algorithms presented are the MAP (maximum a posteriori probability) decoding algorithm and the Soft-Output Viterbi Algorithm (SOVA) algorithm. Finally, the minimization of bit error probability in trellis-based MLD is discussed.

  1. Three-dimensional hybrid grid generation using advancing front techniques

    NASA Technical Reports Server (NTRS)

    Steinbrenner, John P.; Noack, Ralph W.

    1995-01-01

    A new 3-dimensional hybrid grid generation technique has been developed, based on ideas of advancing fronts for both structured and unstructured grids. In this approach, structured grids are first generate independently around individual components of the geometry. Fronts are initialized on these structure grids, and advanced outward so that new cells are extracted directly from the structured grids. Employing typical advancing front techniques, cells are rejected if they intersect the existing front or fail other criteria When no more viable structured cells exist further cells are advanced in an unstructured manner to close off the overall domain, resulting in a grid of 'hybrid' form. There are two primary advantages to the hybrid formulation. First, generating blocks with limited regard to topology eliminates the bottleneck encountered when a multiple block system is used to fully encapsulate a domain. Individual blocks may be generated free of external constraints, which will significantly reduce the generation time. Secondly, grid points near the body (presumably with high aspect ratio) will still maintain a structured (non-triangular or tetrahedral) character, thereby maximizing grid quality and solution accuracy near the surface.

  2. Chemically directing d-block heterometallics to nanocrystal surfaces as molecular beacons of surface structure

    DOE PAGES

    Rosen, Evelyn L.; Gilmore, Keith; Sawvel, April M.; ...

    2015-07-28

    Our understanding of structure and bonding in nanoscale materials is incomplete without knowledge of their surface structure. Needed are better surveying capabilities responsive not only to different atoms at the surface, but also their respective coordination environments. We report here that d-block organometallics, when placed at nanocrystal surfaces through heterometallic bonds, serve as molecular beacons broadcasting local surface structure in atomic detail. This unique ability stems from their elemental specificity and the sensitivity of their d-orbital level alignment to local coordination environment, which can be assessed spectroscopically. Re-surfacing cadmium and lead chalcogenide nanocrystals with iron- or ruthenium-based molecular beacons ismore » readily accomplished with trimethylsilylated cyclopentadienyl metal carbonyls. For PbSe nanocrystals with iron-based beacons, we show how core-level X-ray spectroscopies and DFT calculations enrich our understanding of both charge and atomic reorganization at the surface when beacons are bound.« less

  3. Three-Dimensional Cellular Structures Enhanced By Shape Memory Alloys

    NASA Technical Reports Server (NTRS)

    Nathal, Michael V.; Krause, David L.; Wilmoth, Nathan G.; Bednarcyk, Brett A.; Baker, Eric H.

    2014-01-01

    This research effort explored lightweight structural concepts married with advanced smart materials to achieve a wide variety of benefits in airframe and engine components. Lattice block structures were cast from an aerospace structural titanium alloy Ti-6Al-4V and a NiTi shape memory alloy (SMA), and preliminary properties have been measured. A finite element-based modeling approach that can rapidly and accurately capture the deformation response of lattice architectures was developed. The Ti-6-4 and SMA material behavior was calibrated via experimental tests of ligaments machined from the lattice. Benchmark testing of complete lattice structures verified the main aspects of the model as well as demonstrated the advantages of the lattice structure. Shape memory behavior of a sample machined from a lattice block was also demonstrated.

  4. Topology Optimization of Lightweight Lattice Structural Composites Inspired by Cuttlefish Bone

    NASA Astrophysics Data System (ADS)

    Hu, Zhong; Gadipudi, Varun Kumar; Salem, David R.

    2018-03-01

    Lattice structural composites are of great interest to various industries where lightweight multifunctionality is important, especially aerospace. However, strong coupling among the composition, microstructure, porous topology, and fabrication of such materials impedes conventional trial-and-error experimental development. In this work, a discontinuous carbon fiber reinforced polymer matrix composite was adopted for structural design. A reliable and robust design approach for developing lightweight multifunctional lattice structural composites was proposed, inspired by biomimetics and based on topology optimization. Three-dimensional periodic lattice blocks were initially designed, inspired by the cuttlefish bone microstructure. The topologies of the three-dimensional periodic blocks were further optimized by computer modeling, and the mechanical properties of the topology optimized lightweight lattice structures were characterized by computer modeling. The lattice structures with optimal performance were identified.

  5. Block structured adaptive mesh and time refinement for hybrid, hyperbolic + N-body systems

    NASA Astrophysics Data System (ADS)

    Miniati, Francesco; Colella, Phillip

    2007-11-01

    We present a new numerical algorithm for the solution of coupled collisional and collisionless systems, based on the block structured adaptive mesh and time refinement strategy (AMR). We describe the issues associated with the discretization of the system equations and the synchronization of the numerical solution on the hierarchy of grid levels. We implement a code based on a higher order, conservative and directionally unsplit Godunov’s method for hydrodynamics; a symmetric, time centered modified symplectic scheme for collisionless component; and a multilevel, multigrid relaxation algorithm for the elliptic equation coupling the two components. Numerical results that illustrate the accuracy of the code and the relative merit of various implemented schemes are also presented.

  6. Swell Gels to Dumbbell Micelles: Construction of Materials and Nanostructure with Self-assembly

    NASA Astrophysics Data System (ADS)

    Pochan, Darrin

    2007-03-01

    Bionanotechnology, the emerging field of using biomolecular and biotechnological tools for nanostructure or nanotecnology development, provides exceptional opportunity in the design of new materials. Self-assembly of molecules is an attractive materials construction strategy due to its simplicity in application. By considering peptidic or charged synthetic polymer 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. Several molecular systems will be discussed. Synthetic block copolymers with charged corona blocks can be assembled in dilute solution containing multivalent organic counterions to produce micelle structures such as toroids. These ring-like micelles are similar to the toroidal bundling of charged semiflexible biopolymers like DNA in the presence of multivalent counterions. Micelle structure can be tuned between toroids, cylinders, and disks simply by using different concentrations or molecular volumes of organic counterion. In addition, these charged blocks can consist of amino acids as monomers producing block copolypeptides. In addition to the above attributes, block copolypeptides provide the control of block secondary structure to further control self-assembly. Design strategies 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, the intramolecular folding event impart a molecular-level mechanism for environmental responsiveness at the material level (e.g. infinite change in viscosity of a solution to a gel with changes in pH, ionic strength, temperature).

  7. Characterization of a small Terfenol-D transducer in mechanically blocked configuration

    NASA Astrophysics Data System (ADS)

    Faidley, LeAnn E.; Dapino, Marcelo J.; Flatau, Alison B.

    2001-08-01

    In numerous applications, smart material transducers are employed to actuate upon virtually immovable structures, that is, structures whose stiffness approaches infinity in comparison with that of the transducer itself. Such mechanically blocked transducer configurations can be found in applications ranging from seismic testing and isolation of civil structures, to clamping mechanisms in linear or rotational inchworm motors. In addition to providing high blocking forces, smart materials for this type of applications must often be small in size and lightweight in order for design constraints to be met. This paper provides a characterization of the force produced by a 0.9 cm (0.35 in) diameter, 2.0 cm (0.79i in) long Terfenol-D operated under mechanically blocked conditions. Experimental results are shown for several mechanical preloads as well as various magnetic field intensities, waveforms, and frequencies. Optimal levels are deduced and discussed and the results are compared to published data for a PZT transducer of similar size operated in mechanically blocked configuration. The comparison reveals that the Terfenol-D rod provides higher blocking forces than its PZT counterpart. It is thus feasible to employ small magnetostrictive drivers in applications involving zero or near-zero displacement, particularly those based on hybrid magnetostrictive/piezoelectric designs in which high efficiencies are achieved by driving the two electrically complementary transducer materials at electrical resonance.

  8. Hierarchical multiscale hyperporous block copolymer membranes via tunable dual-phase separation

    PubMed Central

    Yoo, Seungmin; Kim, Jung-Hwan; Shin, Myoungsoo; Park, Hyungmin; Kim, Jeong-Hoon; Lee, Sang-Young; Park, Soojin

    2015-01-01

    The rational design and realization of revolutionary porous structures have been long-standing challenges in membrane science. We demonstrate a new class of amphiphilic polystyrene-block-poly(4-vinylpyridine) block copolymer (BCP)–based porous membranes featuring hierarchical multiscale hyperporous structures. The introduction of surface energy–modifying agents and the control of major phase separation parameters (such as nonsolvent polarity and solvent drying time) enable tunable dual-phase separation of BCPs, eventually leading to macro/nanoscale porous structures and chemical functionalities far beyond those accessible with conventional approaches. Application of this BCP membrane to a lithium-ion battery separator affords exceptional improvement in electrochemical performance. The dual-phase separation–driven macro/nanopore construction strategy, owing to its simplicity and tunability, is expected to be readily applicable to a rich variety of membrane fields including molecular separation, water purification, and energy-related devices. PMID:26601212

  9. Non-amine-based dopamine transporter (reuptake) inhibitors retain properties of amine-based progenitors.

    PubMed

    Madras, Bertha K; Fahey, Michele A; Miller, Gregory M; De La Garza, Richard; Goulet, Martin; Spealman, Roger D; Meltzer, Peter C; George, Susan R; O'Dowd, Brian F; Bonab, Ali A; Livni, Eli; Fischman, Alan J

    2003-10-31

    Without exception, therapeutic and addictive drugs that produce their primary effects by blocking monoamine transporters in brain contain an amine nitrogen in their structure. This fundamental canon of drug design was based on a prevailing premise that an amine nitrogen is required to mimic the structures of monoamine neurotransmitters and other natural products. Non-amines, a novel class of compounds that contain no amine nitrogen, block monoamine transporters in the nM range and display markedly high selectivity for monoamine transporters, but not for receptors. Non-amines retain the spectrum of biochemical and pharmacological properties characteristic of amine-bearing counterparts. These novel drugs compel a revision of current concepts of drug-monoamine transporter complex formation and open avenues for discovery of a new generation of therapeutic drugs.

  10. 18 CFR 1304.410 - Navigation restrictions.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ..., structures, land based or water use, shall not be located within the limits of safety harbors and landings established for commercial navigation. (b) Structures shall not be located in such a way as to block the... OF CONSTRUCTION IN THE TENNESSEE RIVER SYSTEM AND REGULATION OF STRUCTURES AND OTHER ALTERATIONS...

  11. 18 CFR 1304.410 - Navigation restrictions.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ..., structures, land based or water use, shall not be located within the limits of safety harbors and landings established for commercial navigation. (b) Structures shall not be located in such a way as to block the... OF CONSTRUCTION IN THE TENNESSEE RIVER SYSTEM AND REGULATION OF STRUCTURES AND OTHER ALTERATIONS...

  12. Colloidosome like structures: self-assembly of silica microrods

    DOE PAGES

    Datskos, P.; Polizos, G.; Bhandari, M.; ...

    2016-03-07

    Self-assembly of one-dimensional structures is attracting a great deal of interest because assembled structures can provide better properties compared to individual building blocks. We demonstrate silica microrod self-assembly by exploiting Pickering emulsion based strategy. Micron-sized silica rods were synthesized employing previously reported methods based on polyvinylpyrrolidone/ pentanol emulsion droplets. Moreover, rods self-assembled to make structures in the range of z10 40 mm. Smooth rods assembled better than segmented rods. Finally, the assembled structures were bonded by weak van der Waals forces.

  13. Grid Work

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Pointwise Inc.'s, Gridgen Software is a system for the generation of 3D (three dimensional) multiple block, structured grids. Gridgen is a visually-oriented, graphics-based interactive code used to decompose a 3D domain into blocks, distribute grid points on curves, initialize and refine grid points on surfaces and initialize volume grid points. Gridgen is available to U.S. citizens and American-owned companies by license.

  14. The CHIC Model: A Global Model for Coupled Binary Data

    ERIC Educational Resources Information Center

    Wilderjans, Tom; Ceulemans, Eva; Van Mechelen, Iven

    2008-01-01

    Often problems result in the collection of coupled data, which consist of different N-way N-mode data blocks that have one or more modes in common. To reveal the structure underlying such data, an integrated modeling strategy, with a single set of parameters for the common mode(s), that is estimated based on the information in all data blocks, may…

  15. Dynamic swelling of tunable full-color block copolymer photonic gels via counterion exchange.

    PubMed

    Lim, Ho Sun; Lee, Jae-Hwang; Walish, Joseph J; Thomas, Edwin L

    2012-10-23

    One-dimensionally periodic block copolymer photonic lamellar gels with full-color tunability as a result of a direct exchange of counteranions were fabricated via a two-step procedure comprising the self-assembly of a hydrophobic block-hydrophilic polyelectrolyte block copolymer, polystyrene-b-poly(2-vinyl pyridine) (PS-b-P2VP), followed by sequential quaternization of the P2VP layers in 1-bromoethane solution. Depending on the hydration characteristics of each counteranion, the selective swelling of the block copolymer lamellar structures leads to large tunability of the photonic stop band from blue to red wavelengths. More extensive quaternization of the P2VP block allows the photonic lamellar gels to swell more and red shift to longer wavelength. Here, we investigate the dynamic swelling behavior in the photonic gel films through time-resolved in situ measurement of UV-vis transmission. We model the swelling behavior using the transfer matrix method based on the experimentally observed reflectivity data with substitution of appropriate counterions. These tunable structural color materials may be attractive for numerous applications such as high-contrast displays without using a backlight, color filters, and optical mirrors for flexible lasing.

  16. Fabrication of honeycomb-structured poly(ethylene glycol)-block-poly(lactic acid) porous films and biomedical applications for cell growth

    NASA Astrophysics Data System (ADS)

    Yao, Bingjian; Zhu, Qingzeng; Yao, Linli; Hao, Jingcheng

    2015-03-01

    A series of poly(ethylene glycol)-block-poly(lactic acid) (PEG-PLA) copolymers with a hydrophobic PLA block of different molecular weights and a fixed length hydrophilic PEG were synthesized successfully and characterized. These amphiphilic block copolymers were used to fabricate honeycomb-structured porous films using the breath figure (BF) templating technique. The surface topology and composition of the highly ordered pattern film were further characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and fluorescence microscopy. The results indicated that the PEG-to-PLA block molecular weight ratio influenced the BF film surface topology. The film with the best ordered pores was obtained with a PEG-to-PLA ratio of 2.0 × 103:3.0 × 104. The self-organization of the hydrophilic PEG chains within the pores was confirmed by XPS and fluorescence labeled PEG. A model is proposed to elucidate the stabilization process of the amphiphilic PEG-PLA aggregated architecture on the water droplet-based templates. In addition, GFP-U87 cell viability has been investigated by MTS test and the cell morphology on the honeycomb-structured PEG-PLA porous film has been evaluated using phase-contrast microscope. This porous film is shown to be suitable as a matrix for cell growth.

  17. Evolvable rough-block-based neural network and its biomedical application to hypoglycemia detection system.

    PubMed

    San, Phyo Phyo; Ling, Sai Ho; Nuryani; Nguyen, Hung

    2014-08-01

    This paper focuses on the hybridization technology using rough sets concepts and neural computing for decision and classification purposes. Based on the rough set properties, the lower region and boundary region are defined to partition the input signal to a consistent (predictable) part and an inconsistent (random) part. In this way, the neural network is designed to deal only with the boundary region, which mainly consists of an inconsistent part of applied input signal causing inaccurate modeling of the data set. Owing to different characteristics of neural network (NN) applications, the same structure of conventional NN might not give the optimal solution. Based on the knowledge of application in this paper, a block-based neural network (BBNN) is selected as a suitable classifier due to its ability to evolve internal structures and adaptability in dynamic environments. This architecture will systematically incorporate the characteristics of application to the structure of hybrid rough-block-based neural network (R-BBNN). A global training algorithm, hybrid particle swarm optimization with wavelet mutation is introduced for parameter optimization of proposed R-BBNN. The performance of the proposed R-BBNN algorithm was evaluated by an application to the field of medical diagnosis using real hypoglycemia episodes in patients with Type 1 diabetes mellitus. The performance of the proposed hybrid system has been compared with some of the existing neural networks. The comparison results indicated that the proposed method has improved classification performance and results in early convergence of the network.

  18. The StreamCat Dataset: Accumulated Attributes for NHDPlusV2 (Version 2.1) Catchments Riparian Buffer for the Conterminous United States: 2010 US Census Housing Unit and Population Density

    EPA Pesticide Factsheets

    This dataset represents the population and housing unit density within individual, local NHDPlusV2 catchments and upstream, contributing watersheds riparian buffers based on 2010 US Census data. Densities are calculated for every block group and watershed averages are calculated for every local NHDPlusV2 catchment(see Data Sources for links to NHDPlusV2 data and Census Data). This data set is derived from The TIGER/Line Files and related database (.dbf) files for the conterminous USA. It was downloaded as Block Group-Level Census 2010 SF1 Data in File Geodatabase Format (ArcGIS version 10.0). The landscape raster (LR) was produced based on the data compiled from the questions asked of all people and about every housing unit. The (block-group population / block group area) and (block-group housing units / block group area) were summarized by local catchment and by watershed to produce local catchment-level and watershed-level metrics as a continuous data type (see Data Structure and Attribute Information for a description).

  19. Microfibres and macroscopic films from the coordination-driven hierarchical self-assembly of cylindrical micelles

    PubMed Central

    Lunn, David J.; Gould, Oliver E. C.; Whittell, George R.; Armstrong, Daniel P.; Mineart, Kenneth P.; Winnik, Mitchell A.; Spontak, Richard J.; Pringle, Paul G.; Manners, Ian

    2016-01-01

    Anisotropic nanoparticles prepared from block copolymers are of growing importance as building blocks for the creation of synthetic hierarchical materials. However, the assembly of these structural units is generally limited to the use of amphiphilic interactions. Here we report a simple, reversible coordination-driven hierarchical self-assembly strategy for the preparation of micron-scale fibres and macroscopic films based on monodisperse cylindrical block copolymer micelles. Coordination of Pd(0) metal centres to phosphine ligands immobilized within the soluble coronas of block copolymer micelles is found to induce intermicelle crosslinking, affording stable linear fibres comprised of micelle subunits in a staggered arrangement. The mean length of the fibres can be varied by altering the micelle concentration, reaction stoichiometry or aspect ratio of the micelle building blocks. Furthermore, the fibres aggregate on drying to form robust, self-supporting macroscopic micelle-based thin films with useful mechanical properties that are analogous to crosslinked polymer networks, but on a longer length scale. PMID:27538877

  20. High-efficiency non-blocking phosphorescent organic light emitting diode with ultrathin emission layer

    NASA Astrophysics Data System (ADS)

    Qiu, Jacky; Helander, Michael G.; Wang, Zhibin; Chang, Yi-Lu; Lu, ZhengHong

    2012-09-01

    Non-blocking Phosphorescent Organic Light Emitting Diode (NB-PHOLED) is a highly simplified device structure that has achieved record high device performance on chlorinated ITO[1], flexible substrates[2], also with Pt based phosphorescent dopants[3] and NB-PHOLED has significantly reduced efficiency roll-off[4]. The principle novel features of NB-PHOLED is the absence of blocking layer in the OLED stack, as well as the absence of organic hole injection layer, this allows for reduction of carrier accumulation in between organic layers and result in higher efficiencies.

  1. A Cost Effective Block Framing Scheme for Underwater Communication

    PubMed Central

    Shin, Soo-Young; Park, Soo-Hyun

    2011-01-01

    In this paper, the Selective Multiple Acknowledgement (SMA) method, based on Multiple Acknowledgement (MA), is proposed to efficiently reduce the amount of data transmission by redesigning the transmission frame structure and taking into consideration underwater transmission characteristics. The method is suited to integrated underwater system models, as the proposed method can handle the same amount of data in a much more compact frame structure without any appreciable loss of reliability. Herein, the performance of the proposed SMA method was analyzed and compared to those of the conventional Automatic Repeat-reQuest (ARQ), Block Acknowledgement (BA), block response, and MA methods. The efficiency of the underwater sensor network, which forms a large cluster and mostly contains uplink data, is expected to be improved by the proposed method. PMID:22247689

  2. Hybrid Grid Techniques for Propulsion Applications

    NASA Technical Reports Server (NTRS)

    Koomullil, Roy P.; Soni, Bharat K.; Thornburg, Hugh J.

    1996-01-01

    During the past decade, computational simulation of fluid flow for propulsion activities has progressed significantly, and many notable successes have been reported in the literature. However, the generation of a high quality mesh for such problems has often been reported as a pacing item. Hence, much effort has been expended to speed this portion of the simulation process. Several approaches have evolved for grid generation. Two of the most common are structured multi-block, and unstructured based procedures. Structured grids tend to be computationally efficient, and have high aspect ratio cells necessary for efficently resolving viscous layers. Structured multi-block grids may or may not exhibit grid line continuity across the block interface. This relaxation of the continuity constraint at the interface is intended to ease the grid generation process, which is still time consuming. Flow solvers supporting non-contiguous interfaces require specialized interpolation procedures which may not ensure conservation at the interface. Unstructured or generalized indexing data structures offer greater flexibility, but require explicit connectivity information and are not easy to generate for three dimensional configurations. In addition, unstructured mesh based schemes tend to be less efficient and it is difficult to resolve viscous layers. Recently hybrid or generalized element solution and grid generation techniques have been developed with the objective of combining the attractive features of both structured and unstructured techniques. In the present work, recently developed procedures for hybrid grid generation and flow simulation are critically evaluated, and compared to existing structured and unstructured procedures in terms of accuracy and computational requirements.

  3. Hierarchical Nanostructures Self-Assembled from a Mixture System Containing Rod-Coil Block Copolymers and Rigid Homopolymers

    PubMed Central

    Li, Yongliang; Jiang, Tao; Lin, Shaoliang; Lin, Jiaping; Cai, Chunhua; Zhu, Xingyu

    2015-01-01

    Self-assembly behavior of a mixture system containing rod-coil block copolymers and rigid homopolymers was investigated by using Brownian dynamics simulations. The morphologies of formed hierarchical self-assemblies were found to be dependent on the Lennard-Jones (LJ) interaction εRR between rod blocks, lengths of rod and coil blocks in copolymer, and mixture ratio of block copolymers to homopolymers. As the εRR value decreases, the self-assembled structures of mixtures are transformed from an abacus-like structure to a helical structure, to a plain fiber, and finally are broken into unimers. The order parameter of rod blocks was calculated to confirm the structure transition. Through varying the length of rod and coil blocks, the regions of thermodynamic stability of abacus, helix, plain fiber, and unimers were mapped. Moreover, it was discovered that two levels of rod block ordering exist in the helices. The block copolymers are helically wrapped on the homopolymer bundles to form helical string, while the rod blocks are twistingly packed inside the string. In addition, the simulation results are in good agreement with experimental observations. The present work reveals the mechanism behind the formation of helical (experimentally super-helical) structures and may provide useful information for design and preparation of the complex structures. PMID:25965726

  4. Multi-purpose greenhouse of changeable geometry (MGCG)

    NASA Astrophysics Data System (ADS)

    Kordium, V.; Kornejchuk, A.

    In the frames of scientific program of National Cosmic Agency of Ukraine the multipurpose greenhouse is being developed. It is destined for the performance of biological and biotechnological experiments as well as for planting of fast growing vegetable cultures for crew ration enrichment and positive psychological influence under the conditions of long-term flight in the international space station or in other cosmic flying objects. Main principle of greenhouse arrangement is the existence of unified modules. Their sets and combinations permit to form executively different space greenhouse configurations. The minimal structural greenhouse unit suitable either for construction of total configuration or for autonomous functioning, is a carrying composite platform (CCP). The experimental vegetative module (EVM) and the module, supporting microclimate needed inside EVM, are launched to CCP. The amount of these modules and their configuration depend on quantity and complexity of tasks to be solved as well as on duration of their performance. These modules form the experimental block. Four modules of much larger sizes, which form experimentally technological block, are used for further studies of objectives approved in the experimental block. The technologies developed for growing plants are used in the third, technological block, which is a one large vegetative module. All three greenhouse blocks can be changed in their sizes in three dimensions, and function either in a complete greenhouse structure, or autonomously. The control is performed from a board computer, or, if necessary, it is governed with automation devices placed on a front panel of blocks. All three blocks are pulled out along the directing base into the station passage, and this makes free access to the base modules, convenient work with them, and à good survey.

  5. Structure and Dynamics of Ionic Block Copolymer Melts: Computational Study

    DOE PAGES

    Aryal, Dipak; Agrawal, Anupriya; Perahia, Dvora; ...

    2017-09-06

    Structure and dynamics of melts of copolymers with an ABCBA topology, where C is an ionizable block, have been studied by fully atomistic molecular dynamics (MD) simulations. Introducing an ionizable block for functionality adds a significant element to the coupled set of interactions that determine the structure and dynamics of the macromolecule. The polymer consists of a randomly sulfonated polystyrene C block tethered to a flexible poly(ethylene-r-propylene) bridge B and end-capped with poly(tert-butylstyrene) A. The chemical structure and topology of these polymers constitute a model for incorporation of ionic blocks within a framework that provides tactility and mechanical stability. Heremore » in this paper we resolve the structure and dynamics of a structured polymer on the nanoscale constrained by ionic clusters. We find that the melts form intertwined networks of the A and C blocks independent of the degree of sulfonation of the C block with no long-range order. The cluster cohesiveness and morphology affect both macroscopic translational motion and segmental dynamics of all the blocks.« less

  6. Structure and Dynamics of Ionic Block Copolymer Melts: Computational Study

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

    Aryal, Dipak; Agrawal, Anupriya; Perahia, Dvora

    Structure and dynamics of melts of copolymers with an ABCBA topology, where C is an ionizable block, have been studied by fully atomistic molecular dynamics (MD) simulations. Introducing an ionizable block for functionality adds a significant element to the coupled set of interactions that determine the structure and dynamics of the macromolecule. The polymer consists of a randomly sulfonated polystyrene C block tethered to a flexible poly(ethylene-r-propylene) bridge B and end-capped with poly(tert-butylstyrene) A. The chemical structure and topology of these polymers constitute a model for incorporation of ionic blocks within a framework that provides tactility and mechanical stability. Heremore » in this paper we resolve the structure and dynamics of a structured polymer on the nanoscale constrained by ionic clusters. We find that the melts form intertwined networks of the A and C blocks independent of the degree of sulfonation of the C block with no long-range order. The cluster cohesiveness and morphology affect both macroscopic translational motion and segmental dynamics of all the blocks.« less

  7. The Structure of the Onega Downthrown Block and Adjacent Geological Objects According to the Microseismic Sounding Method

    NASA Astrophysics Data System (ADS)

    Danilov, Konstantin B.

    2017-07-01

    The geological structure of the major part of the Arkhangelsk region in the North-West Russia has been poorly studied. In the present work, the microseismic sounding method was, for the first time, used to carry out a detailed geological-geophysical survey in the region. The particles motion study confirmed the results of mathematical modeling of the smallest imaged heterogeneity and resolution of the method. The microseism stability study allowed to determine the amount of error of the microseismic sounding method which is 1-2 dB. Two geophysical cross sections of the north-eastern and south-western boundaries of the Onega downthrown block were studied. The method was shown to allow obtaining seismic images with a high precision in the horizontal direction at relatively low costs in terms of time and finances. The obtained data provided additional information about the structure of the crust, which was consistent with the known geological and geophysical information for the surveyed area. Based on the data, it was concluded that the main reasons of the dissonance of geological information were most likely the division of the downthrown block into the northern and southern blocks and horizontal displacement of the layer to the North at a depth ranging from 3 to 5 km. It was suggested that the most active tectonic processes, including eruptions of ancient volcanoes, occurred in the northern block. Two benches at the studied downthrown block were allocated at the depths of 5 and 10 km.

  8. Block Copolymer Micellization as a Protection Strategy for DNA Origami.

    PubMed

    Agarwal, Nayan P; Matthies, Michael; Gür, Fatih N; Osada, Kensuke; Schmidt, Thorsten L

    2017-05-08

    DNA nanotechnology enables the synthesis of nanometer-sized objects that can be site-specifically functionalized with a large variety of materials. For these reasons, DNA-based devices such as DNA origami are being considered for applications in molecular biology and nanomedicine. However, many DNA structures need a higher ionic strength than that of common cell culture buffers or bodily fluids to maintain their integrity and can be degraded quickly by nucleases. To overcome these deficiencies, we coated several different DNA origami structures with a cationic poly(ethylene glycol)-polylysine block copolymer, which electrostatically covered the DNA nanostructures to form DNA origami polyplex micelles (DOPMs). This straightforward, cost-effective, and robust route to protect DNA-based structures could therefore enable applications in biology and nanomedicine where unprotected DNA origami would be degraded. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Multiple-length-scale deformation analysis in a thermoplastic polyurethane

    PubMed Central

    Sui, Tan; Baimpas, Nikolaos; Dolbnya, Igor P.; Prisacariu, Cristina; Korsunsky, Alexander M.

    2015-01-01

    Thermoplastic polyurethane elastomers enjoy an exceptionally wide range of applications due to their remarkable versatility. These block co-polymers are used here as an example of a structurally inhomogeneous composite containing nano-scale gradients, whose internal strain differs depending on the length scale of consideration. Here we present a combined experimental and modelling approach to the hierarchical characterization of block co-polymer deformation. Synchrotron-based small- and wide-angle X-ray scattering and radiography are used for strain evaluation across the scales. Transmission electron microscopy image-based finite element modelling and fast Fourier transform analysis are used to develop a multi-phase numerical model that achieves agreement with the combined experimental data using a minimal number of adjustable structural parameters. The results highlight the importance of fuzzy interfaces, that is, regions of nanometre-scale structure and property gradients, in determining the mechanical properties of hierarchical composites across the scales. PMID:25758945

  10. Cationic polymers for DNA origami coating - examining their binding efficiency and tuning the enzymatic reaction rates

    NASA Astrophysics Data System (ADS)

    Kiviaho, Jenny K.; Linko, Veikko; Ora, Ari; Tiainen, Tony; Järvihaavisto, Erika; Mikkilä, Joona; Tenhu, Heikki; Nonappa, Affc; Kostiainen, Mauri A.

    2016-06-01

    DNA origamis are fully tailored, programmable, biocompatible and readily functionalizable nanostructures that provide an excellent foundation for the development of sophisticated drug-delivery systems. However, the DNA origami objects suffer from certain drawbacks such as low cell-transfection rates and low stability. A great deal of studies on polymer-based transfection agents, mainly focusing on polyplex formation and toxicity, exists. In this study, the electrostatic binding between a brick-like DNA origami and cationic block-copolymers was explored. The effect of the polymer structure on the binding was investigated and the toxicity of the polymer-origami complexes evaluated. The study shows that all of the analyzed polymers had a suitable binding efficiency irrespective of the block structure. It was also observed that the toxicity of polymer-origami complexes was insignificant at the biologically relevant concentration levels. Besides brick-like DNA origamis, tubular origami carriers equipped with enzymes were also coated with the polymers. By adjusting the amount of cationic polymers that cover the DNA structures, we showed that it is possible to control the enzyme kinetics of the complexes. This work gives a starting point for further development of biocompatible and effective polycation-based block copolymers that can be used in coating different DNA origami nanostructures for various bioapplications.DNA origamis are fully tailored, programmable, biocompatible and readily functionalizable nanostructures that provide an excellent foundation for the development of sophisticated drug-delivery systems. However, the DNA origami objects suffer from certain drawbacks such as low cell-transfection rates and low stability. A great deal of studies on polymer-based transfection agents, mainly focusing on polyplex formation and toxicity, exists. In this study, the electrostatic binding between a brick-like DNA origami and cationic block-copolymers was explored. The effect of the polymer structure on the binding was investigated and the toxicity of the polymer-origami complexes evaluated. The study shows that all of the analyzed polymers had a suitable binding efficiency irrespective of the block structure. It was also observed that the toxicity of polymer-origami complexes was insignificant at the biologically relevant concentration levels. Besides brick-like DNA origamis, tubular origami carriers equipped with enzymes were also coated with the polymers. By adjusting the amount of cationic polymers that cover the DNA structures, we showed that it is possible to control the enzyme kinetics of the complexes. This work gives a starting point for further development of biocompatible and effective polycation-based block copolymers that can be used in coating different DNA origami nanostructures for various bioapplications. Electronic supplementary information (ESI) available: Details of materials, syntheses of the polymers, fabrication and purification of DNA origamis, luminescence decay assays, agarose gel electrophoresis, ethidium bromide displacement assay, MTT assay and TEM characterization. See DOI: 10.1039/c5nr08355a

  11. Mechanics of distributed fault and block rotation

    NASA Technical Reports Server (NTRS)

    Nur, A.; Scotti, O.; Ron, H.

    1989-01-01

    Paleomagnetic data, structural geology, and rock mechanics are used to explore the validity and significance of the block rotation concept. The analysis is based on data from Northern Israel, where fault slip and spacing are used to predict block rotation; the Mojave Desert, with well documented strike-slip sets; the Lake Mead, Nevada fault system with well-defined sets of strike-slip faults; and the San Gabriel Mountains domain with a multiple set of strike-slip faults. The results of the analysis indicate that block rotations can have a profound influence on the interpretation of geodetic measurments and the inversion of geodetic data. Furthermore, the block rotations and domain boundaries may be involved in creating the heterogeneities along active fault systems which may be responsible for the initiation and termination of earthquake rupture.

  12. Deformation History of the Haymana Basin: Structural Records of Closure-Collision and Subsequent Convergence (Indentation) Events at the North-Central Neotethys (Central Anatolia, Turkey)

    NASA Astrophysics Data System (ADS)

    Gülyüz, Erhan; Özkaptan, Murat; Kaymakcı, Nuretdin

    2016-04-01

    Gondwana- (Tauride Platfrom and Kırşehir Block) and Eurasia (Pontides) - derived continental blocks bound the Haymana basin, in the south and north, respectively. Boundaries between these blocks are signed by İzmir-Ankara-Erzincan and debatable Intra-Tauride Suture zones which are straddled by the Haymana Basin in the region. In this regard, deformation recorded in the upper Cretaceous to middle Eocene deposits of the basin is mainly controlled by the relative movements of these blocks. Therefore, understanding the structural evolution of the Haymana Basin in a spatio-temporal concept is crucial to shed some light on some debatable issues such as ; (1) timing of late stage subduction histories of various branches of Neotethys and subsequent collision events, (2) effects of post-collisional tectonic activity in the Haymana region. Fault kinematic analyses (based on 623 fault-slip data from 73 stations) indicate that the basin was subjected to initially N-S to NNE-SSW extension until middle Paleocene and then N-S- to NNE-SSW- directed continuous compression and coeval E-W to ESE-WNW extension up to middle Miocene. These different deformation phases correspond to the fore-arc (closure) and foreland (collision and further convergence) stages of the basin. Additionally, fold analyses (based on 1017 bedding attitudes) and structural mapping studies show that development of folds and major faults are coeval and they can be explained by principle stress orientations of the second deformation phase. The Haymana basin is, based on the trends of E-W- and WNW-ESE- directed structures at the south-eastern and the north-western parts of the basin, respectively, divided into two structural segments. The balanced cross-sections also indicate ~4% and ~25% shortening at the north-western and south-eastern segments, respectively. The differences in amounts of shortenings are explained by reduce in effectiveness zone of basin-bounding thrust faults towards west. On the other hand, the boundary of the segments is defined as an intra-basinal strike-slip system which is thought to be developed together with late stage activities of the basin bounding thrust (or reverse) faults (Dereköy and İnler faults) in response to the north-westward movement of the northern segment of the Kırşehir block. It is proposed that the Haymana basin was initially evolved under the influences of subduction related extensional setting until middle Paleocene, and latterly foreland settings in front of a south-vergent fold and thrust belt developed during collision and post-collisional convergence until middle Miocene. Additionally, the north-westward movement and indentation of the Kırşehir Block caused structural segmentation and rotation events in the basin.

  13. Connecting Molecular Dynamics Simulations and Fluids Density Functional Theory of Block Copolymers

    NASA Astrophysics Data System (ADS)

    Hall, Lisa

    Increased understanding and precise control over the nanoscale structure and dynamics of microphase separated block copolymers would advance development of mechanically robust but conductive materials for battery electrolytes, among other applications. Both coarse-grained molecular dynamics (MD) simulations and fluids (classical) density functional theory (fDFT) can capture the microphase separation of block copolymers, using similar monomer-based chain models and including local packing effects. Equilibrium free energies of various microphases are readily accessible from fDFT, which allows us to efficiently determine the equilibrium nanostructure over a large parameter space. Meanwhile, MD allows us to visualize specific polymer conformations in 3D over time and to calculate dynamic properties. The fDFT density profiles are used to initialize the MD simulations; this ensures the MD proceeds in the appropriate microphase separated state rather than in a metastable structure (useful especially for nonlamellar structures). The simulations equilibrate more quickly than simulations initialized with a random state, which is significant especially for long chains. We apply these methods to study the interfacial behavior and microphase separated structure of diblock and tapered block copolymers. Tapered copolymers consist of pure A and B monomer blocks on the ends separated by a tapered region that smoothly varies from A to B (or from B to A for an inverse taper). Intuitively, tapering increases the segregation strength required for the material to microphase separate and increases the width of the interfacial region. Increasing normal taper length yields a lower domain spacing and increased polymer mobility, while larger inverse tapers correspond to even lower domain spacing but decreased mobility. Thus the changes in dynamics with tapering cannot be explained by mapping to a diblock system at an adjusted effective segregation strength. This material is based upon work supported by the National Science Foundation under Grant 1454343 and the Department of Energy under Grant DE-SC0014209.

  14. A “fullerene-carbon nanotube” structure with tunable mechanical properties

    NASA Astrophysics Data System (ADS)

    Ji, W. M.; Zhang, L. W.; Liew, K. M.

    2018-03-01

    Carbon-based nanostructures have drawn tremendous research interest and become promising building blocks for the new generation of smart sensors and devices. Utilizing a bottom-up strategy, the chemical interconnecting sp 3 covalent bond between carbon building blocks is an efficient way to enhance its Young's modulus and ductility. The formation of sp 3 covalent bond, however, inevitably degrades its ultimate tensile strength caused by stress concentration at the junction. By performing a molecular dynamics simulation of tensile deformation for a fullerene-carbon nanotube (FCNT) structure, we propose a tunable strategy in which fullerenes with various angle energy absorption capacities are utilized as building blocks to tune their ductile behavior, while still maintaining a good ultimate tensile strength of the carbon building blocks. A higher ultimate tensile strength is revealed with the reduction of stress concentration at the junction. A brittle-to-ductile transition during the tensile deformation is detected through the structural modification. The development of ductile behavior is attributed to the improvement of energy propagation ability during the fracture initiation, in which the released energy from bonds fracture is mitigated properly, leading to the further development of mechanical properties.

  15. Super-pixel extraction based on multi-channel pulse coupled neural network

    NASA Astrophysics Data System (ADS)

    Xu, GuangZhu; Hu, Song; Zhang, Liu; Zhao, JingJing; Fu, YunXia; Lei, BangJun

    2018-04-01

    Super-pixel extraction techniques group pixels to form over-segmented image blocks according to the similarity among pixels. Compared with the traditional pixel-based methods, the image descripting method based on super-pixel has advantages of less calculation, being easy to perceive, and has been widely used in image processing and computer vision applications. Pulse coupled neural network (PCNN) is a biologically inspired model, which stems from the phenomenon of synchronous pulse release in the visual cortex of cats. Each PCNN neuron can correspond to a pixel of an input image, and the dynamic firing pattern of each neuron contains both the pixel feature information and its context spatial structural information. In this paper, a new color super-pixel extraction algorithm based on multi-channel pulse coupled neural network (MPCNN) was proposed. The algorithm adopted the block dividing idea of SLIC algorithm, and the image was divided into blocks with same size first. Then, for each image block, the adjacent pixels of each seed with similar color were classified as a group, named a super-pixel. At last, post-processing was adopted for those pixels or pixel blocks which had not been grouped. Experiments show that the proposed method can adjust the number of superpixel and segmentation precision by setting parameters, and has good potential for super-pixel extraction.

  16. High-performance silicon photonic tri-state switch based on balanced nested Mach-Zehnder interferometer.

    PubMed

    Lu, Zeqin; Celo, Dritan; Mehrvar, Hamid; Bernier, Eric; Chrostowski, Lukas

    2017-09-25

    This work proposes a novel silicon photonic tri-state (cross/bar/blocking) switch, featuring high-speed switching, broadband operation, and crosstalk-free performance. The switch is designed based on a 2 × 2 balanced nested Mach-Zehnder interferometer structure with carrier injection phase tuning. As compared to silicon photonic dual-state (cross/bar) switches based on Mach-Zehnder interferometers with carrier injection phase tuning, the proposed switch not only has better performance in cross/bar switching but also provides an extra blocking state. The unique blocking state has a great advantage in applications of N × N switch fabrics, where idle switching elements in the fabrics can be configured to the blocking state for crosstalk suppression. According to our numerical experiments on a fully loaded 8 × 8 dilated Banyan switch fabric, the worst output crosstalk of the 8 × 8 switch can be dramatically suppressed by more than 50 dB, by assigning the blocking state to idle switching elements in the fabric. The results of this work can extend the functionality of silicon photonic switches and significantly improve the performance of on-chip N × N photonic switching technologies.

  17. Electrophoretic build-up of alternately multilayered films and micropatterns based on graphene sheets and nanoparticles and their applications in flexible supercapacitors.

    PubMed

    Niu, Zhiqiang; Du, Jianjun; Cao, Xuebo; Sun, Yinghui; Zhou, Weiya; Hng, Huey Hoon; Ma, Jan; Chen, Xiaodong; Xie, Sishen

    2012-10-22

    Graphene nanosheets and metal nanoparticles (NPs) have been used as nano-building-blocks for assembly into macroscale hybrid structures with promising performance in electrical devices. However, in most graphene and metal NP hybrid structures, the graphene sheets and metal NPs (e.g., AuNPs) do not enable control of the reaction process, orientation of building blocks, and organization at the nanoscale. Here, an electrophoretic layer-by-layer assembly for constructing multilayered reduced graphene oxide (RGO)/AuNP films and lateral micropatterns is presented. This assembly method allows easy control of the nano-architecture of building blocks along the normal direction of the film, including the number and thickness of RGO and AuNP layers, in addition to control of the lateral orientation of the resultant multilayered structures. Conductivity of multilayered RGO/AuNP hybrid nano-architecture shows great improvement caused by a bridging effect of the AuNPs along the out-of-plane direction between the upper and lower RGO layers. The results clearly show the potential of electrophoretic build-up in the fabrication of graphene-based alternately multilayered films and patterns. Finally, flexible supercapacitors based on multilayered RGO/AuNP hybrid films are fabricated, and excellent performance, such as high energy and power densities, are achieved. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Hemicellulose block copolymers made from woods for wide-range directed self-assembly lithography enabling wider range of applicable patterning size

    NASA Astrophysics Data System (ADS)

    Morita, Kazuyo; Yamamoto, Kimiko

    2017-03-01

    Xylan, one of hemicellulose family, block copolymer was newly developed for wide-range directed self-assembly lithography (DSA). Xylan is higher hydrophilic material because of having many hydroxy groups in one molecule. It means that xylan block copolymer has a possibility of high-chi block copolymer. Generally, DSA is focused on microphase separation for smaller size with high-chi block copolymer and not well known for larger size. In this study, xylan block copolymer was confirmed enabling wider range of patterning size, from smaller size to larger size. The key of xylan block copolymer is a new molecular structure of block copolymer and sugar chain control technology. Sugar content is the important parameter for not only micro-phase separation property but also line edge roughness (LER) and defects. Based on the sugar control technology, wide-range (hp 8.3nm to 26nm L/S and CD 10nm to 51nm hole) DSA patterning was demonstrated. Additionally it was confirmed that xylan block copolymer is suitable for sequential infiltration synthesis (SIS) process.

  19. Automatic Blocking Of QR and LU Factorizations for Locality

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

    Yi, Q; Kennedy, K; You, H

    2004-03-26

    QR and LU factorizations for dense matrices are important linear algebra computations that are widely used in scientific applications. To efficiently perform these computations on modern computers, the factorization algorithms need to be blocked when operating on large matrices to effectively exploit the deep cache hierarchy prevalent in today's computer memory systems. Because both QR (based on Householder transformations) and LU factorization algorithms contain complex loop structures, few compilers can fully automate the blocking of these algorithms. Though linear algebra libraries such as LAPACK provides manually blocked implementations of these algorithms, by automatically generating blocked versions of the computations, moremore » benefit can be gained such as automatic adaptation of different blocking strategies. This paper demonstrates how to apply an aggressive loop transformation technique, dependence hoisting, to produce efficient blockings for both QR and LU with partial pivoting. We present different blocking strategies that can be generated by our optimizer and compare the performance of auto-blocked versions with manually tuned versions in LAPACK, both using reference BLAS, ATLAS BLAS and native BLAS specially tuned for the underlying machine architectures.« less

  20. A DNA-Encoded Library of Chemical Compounds Based on Common Scaffolding Structures Reveals the Impact of Ligand Geometry on Protein Recognition.

    PubMed

    Favalli, Nicholas; Biendl, Stefan; Hartmann, Marco; Piazzi, Jacopo; Sladojevich, Filippo; Gräslund, Susanne; Brown, Peter J; Näreoja, Katja; Schüler, Herwig; Scheuermann, Jörg; Franzini, Raphael; Neri, Dario

    2018-06-01

    A DNA-encoded chemical library (DECL) with 1.2 million compounds was synthesized by combinatorial reaction of seven central scaffolds with two sets of 343×492 building blocks. Library screening by affinity capture revealed that for some target proteins, the chemical nature of building blocks dominated the selection results, whereas for other proteins, the central scaffold also crucially contributed to ligand affinity. Molecules based on a 3,5-bis(aminomethyl)benzoic acid core structure were found to bind human serum albumin with a K d value of 6 nm, while compounds with the same substituents on an equidistant but flexible l-lysine scaffold showed 140-fold lower affinity. A 18 nm tankyrase-1 binder featured l-lysine as linking moiety, while molecules based on d-Lysine or (2S,4S)-amino-l-proline showed no detectable binding to the target. This work suggests that central scaffolds which predispose the orientation of chemical building blocks toward the protein target may enhance the screening productivity of encoded libraries. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Two-dimensional infrared spectroscopy reveals the complex behaviour of an amyloid fibril inhibitor

    NASA Astrophysics Data System (ADS)

    Middleton, Chris T.; Marek, Peter; Cao, Ping; Chiu, Chi-Cheng; Singh, Sadanand; Woys, Ann Marie; de Pablo, Juan J.; Raleigh, Daniel P.; Zanni, Martin T.

    2012-05-01

    Amyloid formation has been implicated in the pathology of over 20 human diseases, but the rational design of amyloid inhibitors is hampered by a lack of structural information about amyloid-inhibitor complexes. We use isotope labelling and two-dimensional infrared spectroscopy to obtain a residue-specific structure for the complex of human amylin (the peptide responsible for islet amyloid formation in type 2 diabetes) with a known inhibitor (rat amylin). Based on its sequence, rat amylin should block formation of the C-terminal β-sheet, but at 8 h after mixing, rat amylin blocks the N-terminal β-sheet instead. At 24 h after mixing, rat amylin blocks neither β-sheet and forms its own β-sheet, most probably on the outside of the human fibrils. This is striking, because rat amylin is natively disordered and not previously known to form amyloid β-sheets. The results show that even seemingly intuitive inhibitors may function by unforeseen and complex structural processes.

  2. Continuous structural evolution of calcium carbonate particles: a unifying model of copolymer-mediated crystallization.

    PubMed

    Kulak, Alex N; Iddon, Peter; Li, Yuting; Armes, Steven P; Cölfen, Helmut; Paris, Oskar; Wilson, Rory M; Meldrum, Fiona C

    2007-03-28

    Two double-hydrophilic block copolymers, each comprising a nonionic block and an anionic block comprising pendent aromatic sulfonate groups, were used as additives to modify the crystallization of CaCO3. Marked morphological changes in the CaCO3 particles were observed depending on the reaction conditions used. A poly(ethylene oxide)-b-poly(sodium 4-styrenesulfonate) diblock copolymer was particularly versatile in effecting a morphological change in calcite particles, and a continuous structural transition in the product particles from polycrystalline to mesocrystal to single crystal was observed with variation in the calcium concentration. The existence of this structural sequence provides unique insight into the mechanism of polymer-mediated crystallization. We propose that it reflects continuity in the crystallization mechanism itself, spanning the limits from nonoriented aggregation of nanoparticles to classical ion-by-ion growth. The various pathways to polycrystalline, mesocrystal, and single-crystal particles, which had previously been considered to be distinct, therefore all form part of a unifying crystallization framework based on the aggregation of precursor subunits.

  3. Fabrication of Hyperbranched Block-Statistical Copolymer-Based Prodrug with Dual Sensitivities for Controlled Release.

    PubMed

    Zheng, Luping; Wang, Yunfei; Zhang, Xianshuo; Ma, Liwei; Wang, Baoyan; Ji, Xiangling; Wei, Hua

    2018-01-17

    Dendrimer with hyperbranched structure and multivalent surface is regarded as one of the most promising candidates close to the ideal drug delivery systems, but the clinical translation and scale-up production of dendrimer has been hampered significantly by the synthetic difficulties. Therefore, there is considerable scope for the development of novel hyperbranched polymer that can not only address the drawbacks of dendrimer but maintain its advantages. The reversible addition-fragmentation chain transfer self-condensing vinyl polymerization (RAFT-SCVP) technique has enabled facile preparation of segmented hyperbranched polymer (SHP) by using chain transfer monomer (CTM)-based double-head agent during the past decade. Meanwhile, the design and development of block-statistical copolymers has been proven in our recent studies to be a simple yet effective way to address the extracellular stability vs intracellular high delivery efficacy dilemma. To integrate the advantages of both hyperbranched and block-statistical structures, we herein reported the fabrication of hyperbranched block-statistical copolymer-based prodrug with pH and reduction dual sensitivities using RAFT-SCVP and post-polymerization click coupling. The external homo oligo(ethylene glycol methyl ether methacrylate) (OEGMA) block provides sufficient extracellularly colloidal stability for the nanocarriers by steric hindrance, and the interior OEGMA units incorporated by the statistical copolymerization promote intracellular drug release by facilitating the permeation of GSH and H + for the cleavage of the reduction-responsive disulfide bond and pH-liable carbonate link as well as weakening the hydrophobic encapsulation of drug molecules. The delivery efficacy of the target hyperbranched block-statistical copolymer-based prodrug was evaluated in terms of in vitro drug release and cytotoxicity studies, which confirms both acidic pH and reduction-triggered drug release for inhibiting proliferation of HeLa cells. Interestingly, the simultaneous application of both acidic pH and GSH triggers promoted significantly the cleavage and release of CPT compared to the exertion of single trigger. This study thus developed a facile approach toward hyperbranched polymer-based prodrugs with high therapeutic efficacy for anticancer drug delivery.

  4. Knowledge-based prediction of protein backbone conformation using a structural alphabet.

    PubMed

    Vetrivel, Iyanar; Mahajan, Swapnil; Tyagi, Manoj; Hoffmann, Lionel; Sanejouand, Yves-Henri; Srinivasan, Narayanaswamy; de Brevern, Alexandre G; Cadet, Frédéric; Offmann, Bernard

    2017-01-01

    Libraries of structural prototypes that abstract protein local structures are known as structural alphabets and have proven to be very useful in various aspects of protein structure analyses and predictions. One such library, Protein Blocks, is composed of 16 standard 5-residues long structural prototypes. This form of analyzing proteins involves drafting its structure as a string of Protein Blocks. Predicting the local structure of a protein in terms of protein blocks is the general objective of this work. A new approach, PB-kPRED is proposed towards this aim. It involves (i) organizing the structural knowledge in the form of a database of pentapeptide fragments extracted from all protein structures in the PDB and (ii) applying a knowledge-based algorithm that does not rely on any secondary structure predictions and/or sequence alignment profiles, to scan this database and predict most probable backbone conformations for the protein local structures. Though PB-kPRED uses the structural information from homologues in preference, if available. The predictions were evaluated rigorously on 15,544 query proteins representing a non-redundant subset of the PDB filtered at 30% sequence identity cut-off. We have shown that the kPRED method was able to achieve mean accuracies ranging from 40.8% to 66.3% depending on the availability of homologues. The impact of the different strategies for scanning the database on the prediction was evaluated and is discussed. Our results highlight the usefulness of the method in the context of proteins without any known structural homologues. A scoring function that gives a good estimate of the accuracy of prediction was further developed. This score estimates very well the accuracy of the algorithm (R2 of 0.82). An online version of the tool is provided freely for non-commercial usage at http://www.bo-protscience.fr/kpred/.

  5. Unilateral cervical plexus block for prosthetic laryngoplasty in the standing horse.

    PubMed

    Campoy, L; Morris, T B; Ducharme, N G; Gleed, R D; Martin-Flores, M

    2018-04-20

    Locoregional anaesthetic techniques can facilitate certain surgeries being performed under standing procedural sedation. The second and third spinal cervical nerves (C2, C3) are part of the cervical plexus and provide sensory innervation to the peri-laryngeal structures in people; block of these nerves might permit laryngeal lateralisation surgery in horses. To describe the anatomical basis for an ultrasound-guided cervical plexus block in horses. To compare this block with conventional local anaesthetic tissue infiltration in horses undergoing standing prosthetic laryngoplasty. Cadaveric study followed by a double-blinded prospective clinical trial. A fresh equine cadaver was dissected to characterise the distribution of C2 and C3 to the perilaryngeal structures on the left side. A second cadaver was utilised to correlate ultrasound images with the previously identified structures; a tissue marker was injected to confirm the feasibility of an ultrasound-guided approach to the cervical plexus. In the clinical study, horses were assigned to two groups, CP (n = 17; cervical plexus block) and INF (n = 17; conventional tissue infiltration). Data collection and analyses included time to completion of surgical procedure, sedation time, surgical field conditions and surgeon's perception of block quality. We confirmed that C2 and C3 provided innervation to the perilaryngeal structures. The nerve root of C2 was identified ultrasonographically located between the longus capitis and the cleidomastoideus muscles, caudal to the parotid gland. The CP group was deemed to provide better (P<0.0002) surgical conditions with no differences in the other variables measured. Further studies with larger numbers of horses may be necessary to detect smaller differences in surgical procedure completion time based on the improved surgical filed conditions. For standing unilateral laryngeal surgery, a cervical plexus block is a viable alternative to tissue infiltration and it improves the surgical field conditions. © 2018 EVJ Ltd.

  6. Understanding the Effect of the Dianhydride Structure on the Properties of Semiaromatic Polyimides Containing a Biobased Fatty Diamine

    PubMed Central

    2017-01-01

    In this work we report the effect of the hard block dianhydride structure on the overall properties of partially biobased semiaromatic polyimides. For the study, four polyimides were synthesized using aliphatic fatty dimer diamine (DD1) as the soft block and four different commercially available aromatic dianhydrides as the hard block: 4,4′-(4,4′-isopropylidenediphenoxy) bis(phthalic anhydride) (BPADA), 4,4′-oxidiphthalic anhydride (ODPA), 4,4′-(Hexafluoroisopropylidene) diphthalic anhydride (6FDA), and 3,3′,4,4′-biphenyltetracarboxylic dianhydride (BPDA). The polymers synthesized were fully organo-soluble thermoplastic branched polyimides with glass transition temperatures close to room temperature. The detailed analysis took into account several aspects of the dianhydrides structure (planarity, rigidity, bridging group between the phtalimides, and electronic properties) and related them to the results obtained by differential scanning calorimetry, rheology, fluorescence and broadband dielectric spectroscopy. Moreover, the effects of physical parameters (crystallization and electronic interactions) on the relaxation behavior are discussed. Despite the presence of the bulky branched soft block given by the dimer diamine, all polyimides showed intermolecular charge transfer complexes, whose extent depends on the electronic properties of the dianhydride hard block. Furthermore, the results showed that polyimides containing flexible and bulky hard blocks turned out fully amorphous while the more rigid dianhydride (BPDA) led to a nanophase separated morphology with low degree of crystallinity resulting in constrained segmental relaxation with high effect on its mechanical response with the annealing time. This work represents the first detailed report on the development and characterization of polyimides based on a biobased fatty dimer diamine. The results highlight the potential of polymer property design by controlled engineering of the aromatic dianhydride blocks. PMID:29333351

  7. DNA-Templated Polymerization of Side-Chain-Functionalized Peptide Nucleic Acid Aldehydes

    PubMed Central

    Kleiner, Ralph E.; Brudno, Yevgeny; Birnbaum, Michael E.; Liu, David R.

    2009-01-01

    The DNA-templated polymerization of synthetic building blocks provides a potential route to the laboratory evolution of sequence-defined polymers with structures and properties not necessarily limited to those of natural biopolymers. We previously reported the efficient and sequence-specific DNA-templated polymerization of peptide nucleic acid (PNA) aldehydes. Here, we report the enzyme-free, DNA-templated polymerization of side-chain-functionalized PNA tetramer and pentamer aldehydes. We observed that the polymerization of tetramer and pentamer PNA building blocks with a single lysine-based side chain at various positions in the building block could proceed efficiently and sequence-specifically. In addition, DNA-templated polymerization also proceeded efficiently and in a sequence-specific manner with pentamer PNA aldehydes containing two or three lysine side chains in a single building block to generate more densely functionalized polymers. To further our understanding of side-chain compatibility and expand the capabilities of this system, we also examined the polymerization efficiencies of 20 pentamer building blocks each containing one of five different side-chain groups and four different side-chain regio- and stereochemistries. Polymerization reactions were efficient for all five different side-chain groups and for three of the four combinations of side-chain regio- and stereochemistries. Differences in the efficiency and initial rate of polymerization correlate with the apparent melting temperature of each building block, which is dependent on side-chain regio- and stereochemistry, but relatively insensitive to side-chain structure among the substrates tested. Our findings represent a significant step towards the evolution of sequence-defined synthetic polymers and also demonstrate that enzyme-free nucleic acid-templated polymerization can occur efficiently using substrates with a wide range of side-chain structures, functionalization positions within each building block, and functionalization densities. PMID:18341334

  8. Application of welding simulation to block joints in shipbuilding and assessment of welding-induced residual stresses and distortions

    NASA Astrophysics Data System (ADS)

    Fricke, Wolfgang; Zacke, Sonja

    2014-06-01

    During ship design, welding-induced distortions are roughly estimated as a function of the size of the component as well as the welding process and residual stresses are assumed to be locally in the range of the yield stress. Existing welding simulation methods are very complex and time-consuming and therefore not applicable to large structures like ships. Simplified methods for the estimation of welding effects were and still are subject of several research projects, but mostly concerning smaller structures. The main goal of this paper is the application of a multi-layer welding simulation to the block joint of a ship structure. When welding block joints, high constraints occur due to the ship structure which are assumed to result in accordingly high residual stresses. Constraints measured during construction were realized in a test plant for small-scale welding specimens in order to investigate their and other effects on the residual stresses. Associated welding simulations were successfully performed with fine-mesh finite element models. Further analyses showed that a courser mesh was also able to reproduce the welding-induced reaction forces and hence the residual stresses after some calibration. Based on the coarse modeling it was possible to perform the welding simulation at a block joint in order to investigate the influence of the resulting residual stresses on the behavior of the real structure, showing quite interesting stress distributions. Finally it is discussed whether smaller and idealized models of definite areas of the block joint can be used to achieve the same results offering possibilities to consider residual stresses in the design process.

  9. Observed Human Errors in Interpreting 3D visualizations: implications for Teaching Students how to Comprehend Geological Block Diagrams

    NASA Astrophysics Data System (ADS)

    Bemis, K. G.; Pirl, E.; Chiang, J.; Tremaine, M.

    2009-12-01

    Block diagrams are commonly used to communicate three dimensional geological structures and other phenomena relevant to geological science (e.g., water bodies in the ocean). However, several recent studies have suggested that these 3D visualizations create difficulties for individuals with low to moderate spatial abilities. We have therefore initiated a series of studies to understand what it is about the 3D structures that make them so difficult for some people and also to determine if we can improve people’s understanding of these structures through web-based training not related to geology or other underlying information. Our first study examined what mistakes subjects made in a set of 3D block diagrams designed to represent progressively more difficult internal structures. Each block was shown bisected by a plane either perpendicular or at an angle to the block sides. Five low to medium spatial subjects were asked to draw the features that would appear on the bisecting plane. They were asked to talk aloud as they solved the problem. Each session was videotaped. Using the time it took subjects to solve the problems, the subject verbalizations of their problem solving and the drawings that were found to be in error, we have been able to find common patterns in the difficulties the subjects had with the diagrams. We have used these patterns to generate a set of strategies the subjects used in solving the problems. From these strategies, we are developing methods of teaching. A problem found in earlier work on geology structures was not observed in our study, that is, one of subjects failing to recognize the 2D representation of the block as 3D and drawing the cross-section as a combined version of the visible faces of the object. We attribute this to our experiment introduction, suggesting that even this simple training needs to be carried out with students encountering 3D block diagrams. Other problems subjects had included difficulties in perceptually recognizing variations in layer thicknesses, difficulties in recognizing an internal structure from the visible cues on the block walls, difficulties in mentally constructing objects and intersections that were not perpendicular, and difficulties in keeping track of the number of folds of a layer, and thus, the number of intersections of the layer with the bisecting plane. All of these problems suggest that web-based games giving mass practice with these variations in block diagram representations are likely to give any person appropriate skills in their interpretation. The time to complete the drawings and the errors in the drawings were also correlated with quantifiable properties of the diagrams, e.g., number of layers, number of folds in the layers, angle of bisection of the plane, etc. These will be used in further research to organize the training from easy to hard problems following what is known already about mass practice and developing abstracted skill sets. The plan is to also make the training adaptive, that is, to provide practice in those areas where an individual user is having the most problems.

  10. Using CDBG to Support Community-Based Youth Programs

    ERIC Educational Resources Information Center

    Torrico, Roxana

    2008-01-01

    This brief provides policymakers, stakeholders, community leaders, and program developers working in or with community-based youth programs with a basic understanding of how the Community Development Block Grant (CDBG) is structured, how community-based youth programs fit into CDBG purposes and activities, and how communities nationwide are using…

  11. Formation and Characterization of Anisotropic Block Copolymer Gels

    NASA Astrophysics Data System (ADS)

    Liaw, Chya Yan; Joester, Derk; Burghardt, Wesley; Shull, Kenneth

    2012-02-01

    Cylindrical micelles formed from block copolymer solutions closely mimic biological fibers that are presumed to guide mineral formation during biosynthesis of hard tissues like bone. The goal of our work is to use acrylic block copolymers as oriented templates for studying mineral formation reactions in model systems where the structure of the underlying template is well characterized and reproducible. Self-consistent mean field theory is first applied to investigate the thermodynamically stable micellar morphologies as a function of temperature and block copolymer composition. Small-angle x-ray scattering, optical birefringence and shear rheometry are used to study the morphology development during thermal processing. Initial experiments are based on a thermally-reversible alcohol-soluble system that can be converted to an aqueous gel by hydrolysis of a poly(t-butyl methacrylate) block to a poly(methacrylic acid) block. Aligned cylindrical domains are formed in the alcohol-based system when shear is applied in an appropriate temperature regime, which is below the critical micelle temperature but above the temperature at which the relaxation time of the gels becomes too large. Processing strategies for producing the desired cylindrical morphologies are being developed that account for both thermodynamic and kinetic effects.

  12. Self-assembly strategies for the synthesis of functional nanostructured materials

    NASA Astrophysics Data System (ADS)

    Perego, M.; Seguini, G.

    2016-06-01

    Self-assembly is the autonomous organization of components into patterns or structures without human intervention. This is the approach followed by nature to generate living cells and represents one of the practical strategies to fabricate ensembles of nanostructures. In static self-assembly the formation of ordered structures could require energy but once formed the structures are stable. The introduction of additional regular features in the environment could be used to template the self-assembly guiding the organization of the components and determining the final structure they form. In this regard self-assembly of block copolymers represents a potent platform for fundamental studies at the nanoscale and for application-driven investigation as a tool to fabricate functional nanostructured materials. Block copolymers can hierarchically assemble into chemically distinct domains with size and periodicity on the order of 10nm or below, offering a potentially inexpensive route to generate large-area nanostructured materials. The final structure characteristics of these materials are dictated by the properties of the elementary block copolymers, like chain length, volume fraction or degree of block incompatibility. Modern synthetic chemistry offers the possibility to design these macromolecules with very specific length scales and geometries, directly embodying in the block copolymers the code that drives their self- assembling process. The understanding of the kinetics and thermodynamics of the block copolymer self-assembly process in the bulk phase as well as in thin films represents a fundamental prerequisite toward the exploitation of these materials. Incorporating block copolymer into device fabrication procedures or directly into devices, as active elements, will lead to the development of a new generation of devices fabricated using the fundamental law of nature to our advantage in order to minimize cost and power consumption in the fabrication process. Moreover the capability to precisely organize these nano-objects on appropriate substrates is the key point to support the technological development of new device concepts with predictable characteristics based on these nano-materials. In the next coming years this area of research, at the intersection between fundamental science and technology, is expected to disclose additional insights in the physics of the self-assembly process and to delineate unforeseen applications for these exciting materials.

  13. Local Influence Analysis of Nonlinear Structural Equation Models

    ERIC Educational Resources Information Center

    Lee, Sik-Yum; Tang, Nian-Sheng

    2004-01-01

    By regarding the latent random vectors as hypothetical missing data and based on the conditional expectation of the complete-data log-likelihood function in the EM algorithm, we investigate assessment of local influence of various perturbation schemes in a nonlinear structural equation model. The basic building blocks of local influence analysis…

  14. Silicene Flowers: A Dual Stabilized Silicon Building Block for High-Performance Lithium Battery Anodes.

    PubMed

    Zhang, Xinghao; Qiu, Xiongying; Kong, Debin; Zhou, Lu; Li, Zihao; Li, Xianglong; Zhi, Linjie

    2017-07-25

    Nanostructuring is a transformative way to improve the structure stability of high capacity silicon for lithium batteries. Yet, the interface instability issue remains and even propagates in the existing nanostructured silicon building blocks. Here we demonstrate an intrinsically dual stabilized silicon building block, namely silicene flowers, to simultaneously address the structure and interface stability issues. These original Si building blocks as lithium battery anodes exhibit extraordinary combined performance including high gravimetric capacity (2000 mAh g -1 at 800 mA g -1 ), high volumetric capacity (1799 mAh cm -3 ), remarkable rate capability (950 mAh g -1 at 8 A g -1 ), and excellent cycling stability (1100 mA h g -1 at 2000 mA g -1 over 600 cycles). Paired with a conventional cathode, the fabricated full cells deliver extraordinarily high specific energy and energy density (543 Wh kg ca -1 and 1257 Wh L ca -1 , respectively) based on the cathode and anode, which are 152% and 239% of their commercial counterparts using graphite anodes. Coupled with a simple, cost-effective, scalable synthesis approach, this silicon building block offers a horizon for the development of high-performance batteries.

  15. Nesting in an Object Oriented Language is NOT for the Birds

    NASA Astrophysics Data System (ADS)

    Buhr, P. A.; Zarnke, C. R.

    The notion of nested blocks has come into disfavour or has been ignored in recent program language design. Many of the current object oriented programming languages use subclassing as the sole mechanism to establish relationships between classes and have no general notion of nesting. We argue that nesting (and, more generally, hierarchical organization) is a powerful mechanism that provides facilities that are not otherwise possible in a class based programming language. We agree that traditional block structure and its associated nesting have severe problems, and we suggest several extensions to the notion of blocks and block structure that indirectly make nesting a useful and powerful mechanism, particularly in an object oriented programming system. The main extension is to allow references to definitions from outside of the containing block, thereby making the contained definitions available in a larger scope. References are made using either the name of the containing entity or an instance of the containing entity. The extensions suggest a way to organize the programming environment for a large, multi-user system. These facilities are not available with subclassing, and subclassing provides facilities not available by nesting; hence, an object oriented language can benefit by providing nesting as well.

  16. Importance of crystallinity of anchoring block of semi-solid amphiphilic triblock copolymers in stabilization of silicone nanoemulsions.

    PubMed

    Le Kim, Trang Huyen; Jun, Hwiseok; Nam, Yoon Sung

    2017-10-01

    Polymer emulsifiers solidified at the interface between oil and water can provide exceptional dispersion stability to emulsions due to the formation of unique semi-solid interphase. Our recent works showed that the structural stability of paraffin-in-water emulsions highly depends on the oil wettability of hydrophobic block of methoxy poly(ethylene glycol)-block-poly(ε-caprolactone) (mPEG-b-PCL). Here we investigate the effects of the crystallinity of hydrophobic block of triblock copolymer-based emulsifiers, PCLL-b-PEG-b-PCLL, on the colloidal properties of silicone oil-in-water nanoemulsions. The increased ratio of l-lactide to ε-caprolactone decreases the crystallinity of the hydrophobic block, which in turn reduces the droplet size of silicone oil nanoemulsions due to the increased chain mobility at the interface. All of the prepared nanoemulsions are very stable for a month at 37°C. However, the exposure to repeated freeze-thaw cycles quickly destabilizes the nanoemulsions prepared using the polymer with the reduced crystallinity. This work demonstrates that the anchoring chain crystallization in the semi-solid interphase is critically important for the structural robustness of nanoemulsions under harsh physical stresses. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Hybrid architecture for encoded measurement-based quantum computation

    PubMed Central

    Zwerger, M.; Briegel, H. J.; Dür, W.

    2014-01-01

    We present a hybrid scheme for quantum computation that combines the modular structure of elementary building blocks used in the circuit model with the advantages of a measurement-based approach to quantum computation. We show how to construct optimal resource states of minimal size to implement elementary building blocks for encoded quantum computation in a measurement-based way, including states for error correction and encoded gates. The performance of the scheme is determined by the quality of the resource states, where within the considered error model a threshold of the order of 10% local noise per particle for fault-tolerant quantum computation and quantum communication. PMID:24946906

  18. Hydrophilic interaction chromatography-multiple reaction monitoring mass spectrometry method for basic building block analysis of low molecular weight heparins prepared through nitrous acid depolymerization.

    PubMed

    Sun, Xiaojun; Guo, Zhimou; Yu, Mengqi; Lin, Chao; Sheng, Anran; Wang, Zhiyu; Linhardt, Robert J; Chi, Lianli

    2017-01-06

    Low molecular weight heparins (LMWHs) are important anticoagulant drugs that are prepared through depolymerization of unfractionated heparin. Based on the types of processing reactions and the structures of the products, LMWHs can be divided into different classifications. Enoxaparin is prepared by benzyl esterification and alkaline depolymerization, while dalteparin and nadroparin are prepared through nitrous acid depolymerization followed by borohydride reduction. Compositional analysis of their basic building blocks is an effective way to provide structural information on heparin and LMWHs. However, most current compositional analysis methods have been limited to heparin and enoxaparin. A sensitive and comprehensive approach is needed for detailed investigation of the structure of LMWHs prepared through nitrous acid depolymerization, especially their characteristic saturated non-reducing end (NRE) and 2,5-anhydro-d-mannitol reducing end (RE). A maltose modified hydrophilic interaction column offers improved separation of complicated mixtures of acidic disaccharides and oligosaccharides. A total of 36 basic building blocks were unambiguously identified by high-resolution tandem mass spectrometry (MS). Multiple reaction monitoring (MRM) MS/MS quantification was developed and validated in the analysis of dalteparin and nadroparin samples. Each group of building blocks revealed different aspects of the properties of LMWHs, such as functional motifs required for anticoagulant activity, the structure of heparin starting materials, cleavage sites in the depolymerization reaction, and undesired structural modifications resulting from side reactions. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Froissart bound and self-similarity based models of proton structure functions

    NASA Astrophysics Data System (ADS)

    Choudhury, D. K.; Saikia, Baishali

    2018-03-01

    Froissart bound implies that the total proton-proton cross-section (or equivalently proton structure function) cannot rise faster than log2s ˜log2 1 x. Compatibility of such behavior with the notion of self-similarity in proton structure function was suggested by us sometime back. In the present work, we generalize and improve it further by considering more recent self-similarity based models of proton structure functions and compare with recent data as well as with the model of Block, Durand, Ha and McKay.

  20. Clinic expert information extraction based on domain model and block importance model.

    PubMed

    Zhang, Yuanpeng; Wang, Li; Qian, Danmin; Geng, Xingyun; Yao, Dengfu; Dong, Jiancheng

    2015-11-01

    To extract expert clinic information from the Deep Web, there are two challenges to face. The first one is to make a judgment on forms. A novel method based on a domain model, which is a tree structure constructed by the attributes of query interfaces is proposed. With this model, query interfaces can be classified to a domain and filled in with domain keywords. Another challenge is to extract information from response Web pages indexed by query interfaces. To filter the noisy information on a Web page, a block importance model is proposed, both content and spatial features are taken into account in this model. The experimental results indicate that the domain model yields a precision 4.89% higher than that of the rule-based method, whereas the block importance model yields an F1 measure 10.5% higher than that of the XPath method. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Implementation analysis of RC5 algorithm on Preneel-Govaerts-Vandewalle (PGV) hashing schemes using length extension attack

    NASA Astrophysics Data System (ADS)

    Siswantyo, Sepha; Susanti, Bety Hayat

    2016-02-01

    Preneel-Govaerts-Vandewalle (PGV) schemes consist of 64 possible single-block-length schemes that can be used to build a hash function based on block ciphers. For those 64 schemes, Preneel claimed that 4 schemes are secure. In this paper, we apply length extension attack on those 4 secure PGV schemes which use RC5 algorithm in its basic construction to test their collision resistance property. The attack result shows that the collision occurred on those 4 secure PGV schemes. Based on the analysis, we indicate that Feistel structure and data dependent rotation operation in RC5 algorithm, XOR operations on the scheme, along with selection of additional message block value also give impact on the collision to occur.

  2. Cationic polymers for DNA origami coating - examining their binding efficiency and tuning the enzymatic reaction rates.

    PubMed

    Kiviaho, Jenny K; Linko, Veikko; Ora, Ari; Tiainen, Tony; Järvihaavisto, Erika; Mikkilä, Joona; Tenhu, Heikki; Nonappa; Kostiainen, Mauri A

    2016-06-02

    DNA origamis are fully tailored, programmable, biocompatible and readily functionalizable nanostructures that provide an excellent foundation for the development of sophisticated drug-delivery systems. However, the DNA origami objects suffer from certain drawbacks such as low cell-transfection rates and low stability. A great deal of studies on polymer-based transfection agents, mainly focusing on polyplex formation and toxicity, exists. In this study, the electrostatic binding between a brick-like DNA origami and cationic block-copolymers was explored. The effect of the polymer structure on the binding was investigated and the toxicity of the polymer-origami complexes evaluated. The study shows that all of the analyzed polymers had a suitable binding efficiency irrespective of the block structure. It was also observed that the toxicity of polymer-origami complexes was insignificant at the biologically relevant concentration levels. Besides brick-like DNA origamis, tubular origami carriers equipped with enzymes were also coated with the polymers. By adjusting the amount of cationic polymers that cover the DNA structures, we showed that it is possible to control the enzyme kinetics of the complexes. This work gives a starting point for further development of biocompatible and effective polycation-based block copolymers that can be used in coating different DNA origami nanostructures for various bioapplications.

  3. Development of a Blocking ELISA Using a Monoclonal Antibody to a Dominant Epitope in Non-Structural Protein 3A of Foot-and-Mouth Disease Virus, as a Matching Test for a Negative-Marker Vaccine.

    PubMed

    Fu, Yuanfang; Li, Pinghua; Cao, Yimei; Wang, Na; Sun, Pu; Shi, Qian; Ji, Xincheng; Bao, Huifang; Li, Dong; Chen, Yingli; Bai, Xingwen; Ma, Xueqing; Zhang, Jing; Lu, Zengjun; Liu, Zaixin

    2017-01-01

    Foot-and-mouth disease (FMD) is a devastating animal disease. Strategies for differentiation of infected from vaccinated animals (DIVA) remain very important for controlling disease. Development of an epitope-deleted marker vaccine and accompanying diagnostic method will improve the efficiency of DIVA. Here, a monoclonal antibody (Mab) was found to recognize a conserved "AEKNPLE" epitope spanning amino acids 109-115 of non-structural protein (NSP) 3A of foot-and-mouth disease virus (FMDV; O/Tibet/CHA/99 strain), which could be deleted by a reverse-genetic procedure. In addition, a blocking ELISA was developed based on this Mab against NSP 3A, which could serve as a matching test for a negative-marker vaccine. The criterion of this blocking ELISA was determined by detecting panels of sera from different origins. The serum samples with a percentage inhibition (PI) equal or greater than 50% were considered to be from infected animals, and those with <50% PI were considered to be from non-infected animals. This test showed similar performance when compared with other 2 blocking ELISAs based on an anti-NSP 3B Mab. This is the first report of the DIVA test for an NSP antibody based on an Mab against the conserved and predominant "AEKNPLE" epitope in NSP 3A of FMDV.

  4. Combining a popularity-productivity stochastic block model with a discriminative-content model for general structure detection.

    PubMed

    Chai, Bian-fang; Yu, Jian; Jia, Cai-Yan; Yang, Tian-bao; Jiang, Ya-wen

    2013-07-01

    Latent community discovery that combines links and contents of a text-associated network has drawn more attention with the advance of social media. Most of the previous studies aim at detecting densely connected communities and are not able to identify general structures, e.g., bipartite structure. Several variants based on the stochastic block model are more flexible for exploring general structures by introducing link probabilities between communities. However, these variants cannot identify the degree distributions of real networks due to a lack of modeling of the differences among nodes, and they are not suitable for discovering communities in text-associated networks because they ignore the contents of nodes. In this paper, we propose a popularity-productivity stochastic block (PPSB) model by introducing two random variables, popularity and productivity, to model the differences among nodes in receiving links and producing links, respectively. This model has the flexibility of existing stochastic block models in discovering general community structures and inherits the richness of previous models that also exploit popularity and productivity in modeling the real scale-free networks with power law degree distributions. To incorporate the contents in text-associated networks, we propose a combined model which combines the PPSB model with a discriminative model that models the community memberships of nodes by their contents. We then develop expectation-maximization (EM) algorithms to infer the parameters in the two models. Experiments on synthetic and real networks have demonstrated that the proposed models can yield better performances than previous models, especially on networks with general structures.

  5. Combining a popularity-productivity stochastic block model with a discriminative-content model for general structure detection

    NASA Astrophysics Data System (ADS)

    Chai, Bian-fang; Yu, Jian; Jia, Cai-yan; Yang, Tian-bao; Jiang, Ya-wen

    2013-07-01

    Latent community discovery that combines links and contents of a text-associated network has drawn more attention with the advance of social media. Most of the previous studies aim at detecting densely connected communities and are not able to identify general structures, e.g., bipartite structure. Several variants based on the stochastic block model are more flexible for exploring general structures by introducing link probabilities between communities. However, these variants cannot identify the degree distributions of real networks due to a lack of modeling of the differences among nodes, and they are not suitable for discovering communities in text-associated networks because they ignore the contents of nodes. In this paper, we propose a popularity-productivity stochastic block (PPSB) model by introducing two random variables, popularity and productivity, to model the differences among nodes in receiving links and producing links, respectively. This model has the flexibility of existing stochastic block models in discovering general community structures and inherits the richness of previous models that also exploit popularity and productivity in modeling the real scale-free networks with power law degree distributions. To incorporate the contents in text-associated networks, we propose a combined model which combines the PPSB model with a discriminative model that models the community memberships of nodes by their contents. We then develop expectation-maximization (EM) algorithms to infer the parameters in the two models. Experiments on synthetic and real networks have demonstrated that the proposed models can yield better performances than previous models, especially on networks with general structures.

  6. Efficient low-bit-rate adaptive mesh-based motion compensation technique

    NASA Astrophysics Data System (ADS)

    Mahmoud, Hanan A.; Bayoumi, Magdy A.

    2001-08-01

    This paper proposes a two-stage global motion estimation method using a novel quadtree block-based motion estimation technique and an active mesh model. In the first stage, motion parameters are estimated by fitting block-based motion vectors computed using a new efficient quadtree technique, that divides a frame into equilateral triangle blocks using the quad-tree structure. Arbitrary partition shapes are achieved by allowing 4-to-1, 3-to-1 and 2-1 merge/combine of sibling blocks having the same motion vector . In the second stage, the mesh is constructed using an adaptive triangulation procedure that places more triangles over areas with high motion content, these areas are estimated during the first stage. finally the motion compensation is achieved by using a novel algorithm that is carried by both the encoder and the decoder to determine the optimal triangulation of the resultant partitions followed by affine mapping at the encoder. Computer simulation results show that the proposed method gives better performance that the conventional ones in terms of the peak signal-to-noise ration (PSNR) and the compression ratio (CR).

  7. Determining the Mechanical Properties of Lattice Block Structures

    NASA Technical Reports Server (NTRS)

    Wilmoth, Nathan

    2013-01-01

    Lattice block structures and shape memory alloys possess several traits ideal for solving intriguing new engineering problems in industries such as aerospace, military, and transportation. Recent testing at the NASA Glenn Research Center has investigated the material properties of lattice block structures cast from a conventional aerospace titanium alloy as well as lattice block structures cast from nickel-titanium shape memory alloy. The lattice block structures for both materials were sectioned into smaller subelements for tension and compression testing. The results from the cast conventional titanium material showed that the expected mechanical properties were maintained. The shape memory alloy material was found to be extremely brittle from the casting process and only compression testing was completed. Future shape memory alloy lattice block structures will utilize an adjusted material composition that will provide a better quality casting. The testing effort resulted in baseline mechanical property data from the conventional titanium material for comparison to shape memory alloy materials once suitable castings are available.

  8. Digital Morphing Wing: Active Wing Shaping Concept Using Composite Lattice-Based Cellular Structures.

    PubMed

    Jenett, Benjamin; Calisch, Sam; Cellucci, Daniel; Cramer, Nick; Gershenfeld, Neil; Swei, Sean; Cheung, Kenneth C

    2017-03-01

    We describe an approach for the discrete and reversible assembly of tunable and actively deformable structures using modular building block parts for robotic applications. The primary technical challenge addressed by this work is the use of this method to design and fabricate low density, highly compliant robotic structures with spatially tuned stiffness. This approach offers a number of potential advantages over more conventional methods for constructing compliant robots. The discrete assembly reduces manufacturing complexity, as relatively simple parts can be batch-produced and joined to make complex structures. Global mechanical properties can be tuned based on sub-part ordering and geometry, because local stiffness and density can be independently set to a wide range of values and varied spatially. The structure's intrinsic modularity can significantly simplify analysis and simulation. Simple analytical models for the behavior of each building block type can be calibrated with empirical testing and synthesized into a highly accurate and computationally efficient model of the full compliant system. As a case study, we describe a modular and reversibly assembled wing that performs continuous span-wise twist deformation. It exhibits high performance aerodynamic characteristics, is lightweight and simple to fabricate and repair. The wing is constructed from discrete lattice elements, wherein the geometric and mechanical attributes of the building blocks determine the global mechanical properties of the wing. We describe the mechanical design and structural performance of the digital morphing wing, including their relationship to wind tunnel tests that suggest the ability to increase roll efficiency compared to a conventional rigid aileron system. We focus here on describing the approach to design, modeling, and construction as a generalizable approach for robotics that require very lightweight, tunable, and actively deformable structures.

  9. Digital Morphing Wing: Active Wing Shaping Concept Using Composite Lattice-Based Cellular Structures

    PubMed Central

    Jenett, Benjamin; Calisch, Sam; Cellucci, Daniel; Cramer, Nick; Gershenfeld, Neil; Swei, Sean

    2017-01-01

    Abstract We describe an approach for the discrete and reversible assembly of tunable and actively deformable structures using modular building block parts for robotic applications. The primary technical challenge addressed by this work is the use of this method to design and fabricate low density, highly compliant robotic structures with spatially tuned stiffness. This approach offers a number of potential advantages over more conventional methods for constructing compliant robots. The discrete assembly reduces manufacturing complexity, as relatively simple parts can be batch-produced and joined to make complex structures. Global mechanical properties can be tuned based on sub-part ordering and geometry, because local stiffness and density can be independently set to a wide range of values and varied spatially. The structure's intrinsic modularity can significantly simplify analysis and simulation. Simple analytical models for the behavior of each building block type can be calibrated with empirical testing and synthesized into a highly accurate and computationally efficient model of the full compliant system. As a case study, we describe a modular and reversibly assembled wing that performs continuous span-wise twist deformation. It exhibits high performance aerodynamic characteristics, is lightweight and simple to fabricate and repair. The wing is constructed from discrete lattice elements, wherein the geometric and mechanical attributes of the building blocks determine the global mechanical properties of the wing. We describe the mechanical design and structural performance of the digital morphing wing, including their relationship to wind tunnel tests that suggest the ability to increase roll efficiency compared to a conventional rigid aileron system. We focus here on describing the approach to design, modeling, and construction as a generalizable approach for robotics that require very lightweight, tunable, and actively deformable structures. PMID:28289574

  10. High temperature lithium cells with solid polymer electrolytes

    DOEpatents

    Yang, Jin; Eitouni, Hany Basam; Singh, Mohit

    2017-03-07

    Electrochemical cells that use electrolytes made from new polymer compositions based on poly(2,6-dimethyl-1,4-phenylene oxide) and other high-softening-temperature polymers are disclosed. These materials have a microphase domain structure that has an ionically-conductive phase and a phase with good mechanical strength and a high softening temperature. In one arrangement, the structural block has a softening temperature of about 210.degree. C. These materials can be made with either homopolymers or with block copolymers. Such electrochemical cells can operate safely at higher temperatures than have been possible before, especially in lithium cells. The ionic conductivity of the electrolytes increases with increasing temperature.

  11. Development of a novel biosensing system based on the structural change of a polymerized guanine-quadruplex DNA nanostructure.

    PubMed

    Morita, Yo; Yoshida, Wataru; Savory, Nasa; Han, Sung Woong; Tera, Masayuki; Nagasawa, Kazuo; Nakamura, Chikashi; Sode, Koji; Ikebukuro, Kazunori

    2011-08-15

    By inserting an adenosine aptamer into an aptamer that forms a G-quadruplex, we developed an adaptor molecule, named the Gq-switch, which links an electrode with flavin adenine dinucleotide-dependent glucose dehydrogenase (FADGDH) that is capable of transferring electron to a electrode directly. First, we selected an FADGDH-binding aptamer and identified that its sequence is composed of two blocks of consecutive six guanine bases and it forms a polymerized G-quadruplex structure. Then, we inserted a sequence of an adenosine aptamer between the two blocks of consecutive guanine bases, and we found it also bound to adenosine. Then we named it as Gq-switch. In the absence of adenosine, the Gq-switch-FADGDH complex forms a 30-nm high bulb-shaped structure that changes in the presence of adenosine to give an 8-nm high wire-shaped structure. This structural change brings the FADGDH sufficiently close to the electrode for electron transfer to occur, and the adenosine can be detected from the current produced by the FADGDH. Adenosine was successfully detected with a concentration dependency using the Gq-switch-FADGDH complex immobilized Au electrode by measuring response current to the addition of glucose. Copyright © 2011 Elsevier B.V. All rights reserved.

  12. Graded porous inorganic materials derived from self-assembled block copolymer templates.

    PubMed

    Gu, Yibei; Werner, Jörg G; Dorin, Rachel M; Robbins, Spencer W; Wiesner, Ulrich

    2015-03-19

    Graded porous inorganic materials directed by macromolecular self-assembly are expected to offer unique structural platforms relative to conventional porous inorganic materials. Their preparation to date remains a challenge, however, based on the sparsity of viable synthetic self-assembly pathways to control structural asymmetry. Here we demonstrate the fabrication of graded porous carbon, metal, and metal oxide film structures from self-assembled block copolymer templates by using various backfilling techniques in combination with thermal treatments for template removal and chemical transformations. The asymmetric inorganic structures display mesopores in the film top layers and a gradual pore size increase along the film normal in the macroporous sponge-like support structure. Substructure walls between macropores are themselves mesoporous, constituting a structural hierarchy in addition to the pore gradation. Final graded structures can be tailored by tuning casting conditions of self-assembled templates as well as the backfilling processes. We expect that these graded porous inorganic materials may find use in applications including separation, catalysis, biomedical implants, and energy conversion and storage.

  13. Naming Block Structures: A Multimodal Approach

    ERIC Educational Resources Information Center

    Cohen, Lynn; Uhry, Joanna

    2011-01-01

    This study describes symbolic representation in block play in a culturally diverse suburban preschool classroom. Block play is "multimodal" and can allow children to experiment with materials to represent the world in many forms of literacy. Combined qualitative and quantitative data from seventy-seven block structures were collected and analyzed.…

  14. Significant role of structural fractures in Ren-Qiu buried-block oil field, eastern China

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

    Fei, Q.; Xie-Pei, W.

    1983-03-01

    Ren-qui oil field is in a buried block of Sinian (upper Proterozoic) rocks located in the Ji-zhong depression of the western Bohai Bay basin in eastern China. The main reservoir consists of Sinian dolomite rocks. It is a fault block with a large growth fault on the west side which trends north-northeast with throws of up to 1 km (0.6 mi) or more. The source rocks for the oil are Paleogene age and overlie the Sinian dolomite rocks. The structural fractures are the main factor forming the reservoir of the buried-block oil field. Three structural lines, trending northeast, north-northeast, andmore » northwest, form the regional netted fracture system. The north-northeast growth fault controlled the structural development of the buried block. The block was raised and eroded before the Tertiary sediments were deposited. In the Eocene Epoch, the Ji-zhong depression subsided, but the deposition, faulting, and related uplift of the block happened synchronously as the block was gradually submerged. At the same time, several horizontal and vertical karst zones were formed by the karst water along the netted structural fractures. The Eocene oil source rocks lapped onto the block and so the buried block, with many developed karst fractures, was surrounded by a great thickness of source rocks. As the growth fault developed, the height of the block was increased from 400 m (1300 ft) before the Oligocene to 1300 m (4250 ft) after. As the petroleum was generated, it migrated immediately into the karst fractures of the buried block along the growth fault. The karst-fractured block reservoir has an 800-m (2600-ft) high oil-bearing closure and good connections developed between the karst fractures.« less

  15. Structure and function of μ-conotoxins, peptide-based sodium channel blockers with analgesic activity

    PubMed Central

    Green, Brad R; Bulaj, Grzegorz; Norton, Raymond S

    2015-01-01

    μ-Conotoxins block voltage-gated sodium channels (VGSCs) and compete with tetrodotoxin for binding to the sodium conductance pore. Early efforts identified μ-conotoxins that preferentially blocked the skeletal muscle subtype (NaV1.4). However, the last decade witnessed a significant increase in the number of μ-conotoxins and the range of VGSC subtypes inhibited (NaV1.2, NaV1.3 or NaV1.7). Twenty μ-conotoxin sequences have been identified to date and structure–activity relationship studies of several of these identified key residues responsible for interactions with VGSC subtypes. Efforts to engineer-in subtype specificity are driven by in vivo analgesic and neuromuscular blocking activities. This review summarizes structural and pharmacological studies of μ-conotoxins, which show promise for development of selective blockers of NaV1.2, and perhaps also NaV1.1,1.3 or 1.7. PMID:25406007

  16. Structural Genomics: Correlation Blocks, Population Structure, and Genome Architecture

    PubMed Central

    Hu, Xin-Sheng; Yeh, Francis C.; Wang, Zhiquan

    2011-01-01

    An integration of the pattern of genome-wide inter-site associations with evolutionary forces is important for gaining insights into the genomic evolution in natural or artificial populations. Here, we assess the inter-site correlation blocks and their distributions along chromosomes. A correlation block is broadly termed as the DNA segment within which strong correlations exist between genetic diversities at any two sites. We bring together the population genetic structure and the genomic diversity structure that have been independently built on different scales and synthesize the existing theories and methods for characterizing genomic structure at the population level. We discuss how population structure could shape correlation blocks and their patterns within and between populations. Effects of evolutionary forces (selection, migration, genetic drift, and mutation) on the pattern of genome-wide correlation blocks are discussed. In eukaryote organisms, we briefly discuss the associations between the pattern of correlation blocks and genome assembly features in eukaryote organisms, including the impacts of multigene family, the perturbation of transposable elements, and the repetitive nongenic sequences and GC-rich isochores. Our reviews suggest that the observable pattern of correlation blocks can refine our understanding of the ecological and evolutionary processes underlying the genomic evolution at the population level. PMID:21886455

  17. Production in Pichia pastoris of protein-based polymers with small heterodimer-forming blocks.

    PubMed

    Domeradzka, Natalia E; Werten, Marc W T; de Vries, Renko; de Wolf, Frits A

    2016-05-01

    Some combinations of leucine zipper peptides are capable of forming α-helical heterodimeric coiled coils with very high affinity. These can be used as physical cross-linkers in the design of protein-based polymers that form supramolecular structures, for example hydrogels, upon mixing solutions containing the complementary blocks. Such two-component physical networks are of interest for many applications in biomedicine, pharmaceutics, and diagnostics. This article describes the efficient secretory production of A and B type leucine zipper peptides fused to protein-based polymers in Pichia pastoris. By adjusting the fermentation conditions, we were able to significantly reduce undesirable proteolytic degradation. The formation of A-B heterodimers in mixtures of the purified products was confirmed by size exclusion chromatography. Our results demonstrate that protein-based polymers incorporating functional heterodimer-forming blocks can be produced with P. pastoris in sufficient quantities for use in future supramolecular self-assembly studies and in various applications. © 2015 Wiley Periodicals, Inc.

  18. Adolescent Boys' and Girls' Block Constructions Differ in Structural Balance: A Block-Building Characteristic Related to Math Achievement

    ERIC Educational Resources Information Center

    Casey, Beth M.; Pezaris, Elizabeth E.; Bassi, Julie

    2012-01-01

    Two studies were conducted on block building in adolescents, assessing middle school (Study 1) and high school students (Study 2). Students were asked to build something interesting with blocks. In both samples, the same pattern of gender differences were found; boys built taller structures than girls, and balanced a larger number of blocks on a…

  19. Molecular dynamics study of the encapsulation capability of a PCL-PEO based block copolymer for hydrophobic drugs with different spatial distributions of hydrogen bond donors and acceptors.

    PubMed

    Patel, Sarthak K; Lavasanifar, Afsaneh; Choi, Phillip

    2010-03-01

    Molecular dynamics simulation was used to study the potential of using a block copolymer containing three poly(epsilon-caprolactone) (PCL) blocks of equal length connected to one end of a poly(ethylene oxide) (PEO) block, designated as PEO-b-3PCL, to encapsulate two classes of hydrophobic drugs with distinctively different molecular structures. In particular, the first class of drugs consisted of two cucurbitacin drugs (CuB and CuI) that contain multiple hydrogen bond donors and acceptors evenly distributed on their molecules while the other class of drugs (fenofibrate and nimodipine) contain essentially only clustered hydrogen bond acceptors. In the case of cucurbitacin drugs, the results showed that PEO-b-3PCL lowered the Flory-Huggins interaction parameters (chi) considerably (i.e., increased the drug solubility) compared to the linear di-block copolymer PEO-b-PCL with the same PCL/PEO (w/w) ratio of 1.0. However, the opposite effect was observed for fenofibrate and nimodipine. Analysis of the intermolecular interactions indicates that the number of hydrogen bonds formed between the three PCL blocks and cucurbitacin drugs is significantly higher than that of the linear di-block copolymer. On the other hand, owing to the absence of hydrogen bond donors and the clustering of the hydrogen bond acceptors on the fenofibrate and nimodipine molecules, this significantly reduces the number of hydrogen bonds formed in the multi-PCL block environment, leading to unfavourable chi values. The findings of the present work suggest that multi-hydrophobic block architecture could potentially increase the drug loading for hydrophobic drugs with structures containing evenly distributed multiple hydrogen bond donors and acceptors. (c) 2009 Elsevier Ltd. All rights reserved.

  20. Matriarch: A Python Library for Materials Architecture.

    PubMed

    Giesa, Tristan; Jagadeesan, Ravi; Spivak, David I; Buehler, Markus J

    2015-10-12

    Biological materials, such as proteins, often have a hierarchical structure ranging from basic building blocks at the nanoscale (e.g., amino acids) to assembled structures at the macroscale (e.g., fibers). Current software for materials engineering allows the user to specify polypeptide chains and simple secondary structures prior to molecular dynamics simulation, but is not flexible in terms of the geometric arrangement of unequilibrated structures. Given some knowledge of a larger-scale structure, instructing the software to create it can be very difficult and time-intensive. To this end, the present paper reports a mathematical language, using category theory, to describe the architecture of a material, i.e., its set of building blocks and instructions for combining them. While this framework applies to any hierarchical material, here we concentrate on proteins. We implement this mathematical language as an open-source Python library called Matriarch. It is a domain-specific language that gives the user the ability to create almost arbitrary structures with arbitrary amino acid sequences and, from them, generate Protein Data Bank (PDB) files. In this way, Matriarch is more powerful than commercial software now available. Matriarch can be used in tandem with molecular dynamics simulations and helps engineers design and modify biologically inspired materials based on their desired functionality. As a case study, we use our software to alter both building blocks and building instructions for tropocollagen, and determine their effect on its structure and mechanical properties.

  1. Structural reinterpretation of the Ajo mining district, Pima County, Arizona, based on paleomagnetic and geochronologic studies.

    USGS Publications Warehouse

    Hagstrum, J.T.; Cox, D.P.; Miller, R.J.

    1987-01-01

    The Ajo mining district of southern Arizona is divided into two main structural blocks by the Gibson Arroyo fault. The eastern Camelback Mountain block contains the Late Cretaceous-early Tertiary porphyry copper deposit which has been previously thought to be associated with the displaced apex of a large intrusion exposed by deeper erosion in the western Cardigan Peak block. However, unpublished U-Pb data support a mid-Tertiary age for the western intrusion. The following sequence of mid-Tertiary events in the district are indicated: 1) emplacement of the western intrusion, 2) movement along the Gibson Arroyo fault, 3) unroofing and perhaps tilting of the pluton approx 70o to the south along with the Camelback Mountain block, 4) syntectonic depositions of the Locomotive Fanglomerate and the Ajo Volcanics, 5) continued uplift and tilting to the south totaling 40o to 60o, 6) intrusion of the youngest dikes with attendant alteration and remagnetization of the host rocks, and 7) minor (?) oblique movement along the Gibson Arroyo fault.-from Authors

  2. Domain modeling and grid generation for multi-block structured grids with application to aerodynamic and hydrodynamic configurations

    NASA Technical Reports Server (NTRS)

    Spekreijse, S. P.; Boerstoel, J. W.; Vitagliano, P. L.; Kuyvenhoven, J. L.

    1992-01-01

    About five years ago, a joint development was started of a flow simulation system for engine-airframe integration studies on propeller as well as jet aircraft. The initial system was based on the Euler equations and made operational for industrial aerodynamic design work. The system consists of three major components: a domain modeller, for the graphical interactive subdivision of flow domains into an unstructured collection of blocks; a grid generator, for the graphical interactive computation of structured grids in blocks; and a flow solver, for the computation of flows on multi-block grids. The industrial partners of the collaboration and NLR have demonstrated that the domain modeller, grid generator and flow solver can be applied to simulate Euler flows around complete aircraft, including propulsion system simulation. Extension to Navier-Stokes flows is in progress. Delft Hydraulics has shown that both the domain modeller and grid generator can also be applied successfully for hydrodynamic configurations. An overview is given about the main aspects of both domain modelling and grid generation.

  3. Origami-based tunable truss structures for non-volatile mechanical memory operation.

    PubMed

    Yasuda, Hiromi; Tachi, Tomohiro; Lee, Mia; Yang, Jinkyu

    2017-10-17

    Origami has recently received significant interest from the scientific community as a method for designing building blocks to construct metamaterials. However, the primary focus has been placed on their kinematic applications by leveraging the compactness and auxeticity of planar origami platforms. Here, we present volumetric origami cells-specifically triangulated cylindrical origami (TCO)-with tunable stability and stiffness, and demonstrate their feasibility as non-volatile mechanical memory storage devices. We show that a pair of TCO cells can develop a double-well potential to store bit information. What makes this origami-based approach more appealing is the realization of two-bit mechanical memory, in which two pairs of TCO cells are interconnected and one pair acts as a control for the other pair. By assembling TCO-based truss structures, we experimentally verify the tunable nature of the TCO units and demonstrate the operation of purely mechanical one- and two-bit memory storage prototypes.Origami is a popular method to design building blocks for mechanical metamaterials. Here, the authors assemble a volumetric origami-based structure, predict its axial and rotational movements during folding, and demonstrate the operation of mechanical one- and two-bit memory storage.

  4. Revisiting Parallel Cyclic Reduction and Parallel Prefix-Based Algorithms for Block Tridiagonal System of Equations

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

    Seal, Sudip K; Perumalla, Kalyan S; Hirshman, Steven Paul

    2013-01-01

    Simulations that require solutions of block tridiagonal systems of equations rely on fast parallel solvers for runtime efficiency. Leading parallel solvers that are highly effective for general systems of equations, dense or sparse, are limited in scalability when applied to block tridiagonal systems. This paper presents scalability results as well as detailed analyses of two parallel solvers that exploit the special structure of block tridiagonal matrices to deliver superior performance, often by orders of magnitude. A rigorous analysis of their relative parallel runtimes is shown to reveal the existence of a critical block size that separates the parameter space spannedmore » by the number of block rows, the block size and the processor count, into distinct regions that favor one or the other of the two solvers. Dependence of this critical block size on the above parameters as well as on machine-specific constants is established. These formal insights are supported by empirical results on up to 2,048 cores of a Cray XT4 system. To the best of our knowledge, this is the highest reported scalability for parallel block tridiagonal solvers to date.« less

  5. GPU-accelerated computing for Lagrangian coherent structures of multi-body gravitational regimes

    NASA Astrophysics Data System (ADS)

    Lin, Mingpei; Xu, Ming; Fu, Xiaoyu

    2017-04-01

    Based on a well-established theoretical foundation, Lagrangian Coherent Structures (LCSs) have elicited widespread research on the intrinsic structures of dynamical systems in many fields, including the field of astrodynamics. Although the application of LCSs in dynamical problems seems straightforward theoretically, its associated computational cost is prohibitive. We propose a block decomposition algorithm developed on Compute Unified Device Architecture (CUDA) platform for the computation of the LCSs of multi-body gravitational regimes. In order to take advantage of GPU's outstanding computing properties, such as Shared Memory, Constant Memory, and Zero-Copy, the algorithm utilizes a block decomposition strategy to facilitate computation of finite-time Lyapunov exponent (FTLE) fields of arbitrary size and timespan. Simulation results demonstrate that this GPU-based algorithm can satisfy double-precision accuracy requirements and greatly decrease the time needed to calculate final results, increasing speed by approximately 13 times. Additionally, this algorithm can be generalized to various large-scale computing problems, such as particle filters, constellation design, and Monte-Carlo simulation.

  6. Block Copolymer Membranes for Efficient Capture of a Chemotherapy Drug

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

    Chen, X. Chelsea; Oh, Hee Jeung; Yu, Jay F.

    In this paper, we introduce the use of block copolymer membranes for an emerging application, “drug capture”. The polymer is incorporated in a new class of biomedical devices, referred to as ChemoFilter, which is an image-guided temporarily deployable endovascular device designed to increase the efficacy of chemotherapy-based cancer treatment. We show that block copolymer membranes consisting of functional sulfonated polystyrene end blocks and a structural polyethylene middle block (SSES) are capable of capturing doxorubicin, a chemotherapy drug. We focus on the relationship between morphology of the membrane in the ChemoFilter device and efficacy of doxorubicin capture measured in vitro. Usingmore » small-angle X-ray scattering and cryogenic scanning transmission electron microscopy, we discovered that rapid doxorubicin capture is associated with the presence of water-rich channels in the lamellar-forming S-SES membranes in aqueous environment.« less

  7. Block Copolymer Membranes for Efficient Capture of a Chemotherapy Drug

    DOE PAGES

    Chen, X. Chelsea; Oh, Hee Jeung; Yu, Jay F.; ...

    2016-07-23

    In this paper, we introduce the use of block copolymer membranes for an emerging application, “drug capture”. The polymer is incorporated in a new class of biomedical devices, referred to as ChemoFilter, which is an image-guided temporarily deployable endovascular device designed to increase the efficacy of chemotherapy-based cancer treatment. We show that block copolymer membranes consisting of functional sulfonated polystyrene end blocks and a structural polyethylene middle block (SSES) are capable of capturing doxorubicin, a chemotherapy drug. We focus on the relationship between morphology of the membrane in the ChemoFilter device and efficacy of doxorubicin capture measured in vitro. Usingmore » small-angle X-ray scattering and cryogenic scanning transmission electron microscopy, we discovered that rapid doxorubicin capture is associated with the presence of water-rich channels in the lamellar-forming S-SES membranes in aqueous environment.« less

  8. Quantification of urban structure on building block level utilizing multisensoral remote sensing data

    NASA Astrophysics Data System (ADS)

    Wurm, Michael; Taubenböck, Hannes; Dech, Stefan

    2010-10-01

    Dynamics of urban environments are a challenge to a sustainable development. Urban areas promise wealth, realization of individual dreams and power. Hence, many cities are characterized by a population growth as well as physical development. Traditional, visual mapping and updating of urban structure information of cities is a very laborious and cost-intensive task, especially for large urban areas. For this purpose, we developed a workflow for the extraction of the relevant information by means of object-based image classification. In this manner, multisensoral remote sensing data has been analyzed in terms of very high resolution optical satellite imagery together with height information by a digital surface model to retrieve a detailed 3D city model with the relevant land-use / land-cover information. This information has been aggregated on the level of the building block to describe the urban structure by physical indicators. A comparison between the indicators derived by the classification and a reference classification has been accomplished to show the correlation between the individual indicators and a reference classification of urban structure types. The indicators have been used to apply a cluster analysis to group the individual blocks into similar clusters.

  9. Aircraft propeller induced structure-borne noise

    NASA Technical Reports Server (NTRS)

    Unruh, James F.

    1989-01-01

    A laboratory-based test apparatus employing components typical of aircraft construction was developed that would allow the study of structure-borne noise transmission due to propeller induced wake/vortex excitation of in-wake structural appendages. The test apparatus was employed to evaluate several aircraft installation effects (power plant placement, engine/nacelle mass loading, and wing/fuselage attachment methods) and several structural response modifications for structure-borne noise control (the use of wing blocking mass/fuel, wing damping treaments, and tuned mechanical dampers). Most important was the development of in-flight structure-borne noise transmission detection techniques using a combination of ground-based frequency response function testing and in-flight structural response measurement. Propeller wake/vortex excitation simulation techniques for improved ground-based testing were also developed to support the in-flight structure-borne noise transmission detection development.

  10. Digital Alchemy for Materials Design: Colloids and Beyond

    NASA Astrophysics Data System (ADS)

    van Anders, Greg; Klotsa, Daphne; Karas, Andrew; Dodd, Paul; Glotzer, Sharon

    Starting with the early alchemists, a holy grail of science has been to make desired materials by manipulating basic building blocks. Building blocks that show promise for assembling new complex materials can be synthesized at the nanoscale with attributes that would astonish the ancient alchemists in their versatility. However, this versatility means that connecting building-block attributes to bulk structure is both necessary for rationally engineering materials and difficult because building block attributes can be altered in many ways. We show how to exploit the malleability of colloidal nanoparticle ``elements'' to quantitatively link building-block attributes to bulk structure through a statistical thermodynamic framework we term ``digital alchemy''. We use this framework to optimize building blocks for a given target structure and to determine which building-block attributes are most important to control for self-assembly, through a set of novel thermodynamic response functions. We thereby establish direct links between the attributes of colloidal building blocks and the bulk structures they form. Moreover, our results give concrete solutions to the more general conceptual challenge of optimizing emergent behaviors in nature and can be applied to other types of matter.

  11. Two-dimensional phase separated structures of block copolymers on solids

    NASA Astrophysics Data System (ADS)

    Sen, Mani; Jiang, Naisheng; Endoh, Maya; Koga, Tadanori; Ribbe, Alexander

    The fundamental, yet unsolved question in block copolymer (BCP) thin films is the self-organization process of BCPs at the solid-polymer melt interface. We here focus on the self-organization processes of cylinder-forming polystyrene-block-poly (4-vinylpyridine) diblock copolymer and lamellar-forming poly (styrene-block-butadiene-block-styrene) triblock copolymer on Si substrates as model systems. In order to reveal the buried interfacial structures, the following experimental protocols were utilized: the BCP monolayer films were annealed under vacuum at T>Tg of the blocks (to equilibrate the melts); vitrification of the annealed BCP films via rapid quench to room temperature; subsequent intensive solvent leaching (to remove unadsorbed chains) with chloroform, a non-selective good solvent for the blocks. The strongly bound BCP layers were then characterized by using atomic force microscopy, scanning electron microscopy, grazing incidence small angle X-ray scattering, and X-ray reflectivity. The results showed that both blocks lie flat on the substrate, forming the two-dimensional, randomly phase-separated structure irrespective of their microdomain structures and interfacial energetics. Acknowledgement of financial support from NSF Grant (CMMI -1332499).

  12. SVM-PB-Pred: SVM based protein block prediction method using sequence profiles and secondary structures.

    PubMed

    Suresh, V; Parthasarathy, S

    2014-01-01

    We developed a support vector machine based web server called SVM-PB-Pred, to predict the Protein Block for any given amino acid sequence. The input features of SVM-PB-Pred include i) sequence profiles (PSSM) and ii) actual secondary structures (SS) from DSSP method or predicted secondary structures from NPS@ and GOR4 methods. There were three combined input features PSSM+SS(DSSP), PSSM+SS(NPS@) and PSSM+SS(GOR4) used to test and train the SVM models. Similarly, four datasets RS90, DB433, LI1264 and SP1577 were used to develop the SVM models. These four SVM models developed were tested using three different benchmarking tests namely; (i) self consistency, (ii) seven fold cross validation test and (iii) independent case test. The maximum possible prediction accuracy of ~70% was observed in self consistency test for the SVM models of both LI1264 and SP1577 datasets, where PSSM+SS(DSSP) input features was used to test. The prediction accuracies were reduced to ~53% for PSSM+SS(NPS@) and ~43% for PSSM+SS(GOR4) in independent case test, for the SVM models of above two same datasets. Using our method, it is possible to predict the protein block letters for any query protein sequence with ~53% accuracy, when the SP1577 dataset and predicted secondary structure from NPS@ server were used. The SVM-PB-Pred server can be freely accessed through http://bioinfo.bdu.ac.in/~svmpbpred.

  13. An electrostatic Particle-In-Cell code on multi-block structured meshes

    NASA Astrophysics Data System (ADS)

    Meierbachtol, Collin S.; Svyatskiy, Daniil; Delzanno, Gian Luca; Vernon, Louis J.; Moulton, J. David

    2017-12-01

    We present an electrostatic Particle-In-Cell (PIC) code on multi-block, locally structured, curvilinear meshes called Curvilinear PIC (CPIC). Multi-block meshes are essential to capture complex geometries accurately and with good mesh quality, something that would not be possible with single-block structured meshes that are often used in PIC and for which CPIC was initially developed. Despite the structured nature of the individual blocks, multi-block meshes resemble unstructured meshes in a global sense and introduce several new challenges, such as the presence of discontinuities in the mesh properties and coordinate orientation changes across adjacent blocks, and polyjunction points where an arbitrary number of blocks meet. In CPIC, these challenges have been met by an approach that features: (1) a curvilinear formulation of the PIC method: each mesh block is mapped from the physical space, where the mesh is curvilinear and arbitrarily distorted, to the logical space, where the mesh is uniform and Cartesian on the unit cube; (2) a mimetic discretization of Poisson's equation suitable for multi-block meshes; and (3) a hybrid (logical-space position/physical-space velocity), asynchronous particle mover that mitigates the performance degradation created by the necessity to track particles as they move across blocks. The numerical accuracy of CPIC was verified using two standard plasma-material interaction tests, which demonstrate good agreement with the corresponding analytic solutions. Compared to PIC codes on unstructured meshes, which have also been used for their flexibility in handling complex geometries but whose performance suffers from issues associated with data locality and indirect data access patterns, PIC codes on multi-block structured meshes may offer the best compromise for capturing complex geometries while also maintaining solution accuracy and computational efficiency.

  14. An electrostatic Particle-In-Cell code on multi-block structured meshes

    DOE PAGES

    Meierbachtol, Collin S.; Svyatskiy, Daniil; Delzanno, Gian Luca; ...

    2017-09-14

    We present an electrostatic Particle-In-Cell (PIC) code on multi-block, locally structured, curvilinear meshes called Curvilinear PIC (CPIC). Multi-block meshes are essential to capture complex geometries accurately and with good mesh quality, something that would not be possible with single-block structured meshes that are often used in PIC and for which CPIC was initially developed. In spite of the structured nature of the individual blocks, multi-block meshes resemble unstructured meshes in a global sense and introduce several new challenges, such as the presence of discontinuities in the mesh properties and coordinate orientation changes across adjacent blocks, and polyjunction points where anmore » arbitrary number of blocks meet. In CPIC, these challenges have been met by an approach that features: (1) a curvilinear formulation of the PIC method: each mesh block is mapped from the physical space, where the mesh is curvilinear and arbitrarily distorted, to the logical space, where the mesh is uniform and Cartesian on the unit cube; (2) a mimetic discretization of Poisson's equation suitable for multi-block meshes; and (3) a hybrid (logical-space position/physical-space velocity), asynchronous particle mover that mitigates the performance degradation created by the necessity to track particles as they move across blocks. The numerical accuracy of CPIC was verified using two standard plasma–material interaction tests, which demonstrate good agreement with the corresponding analytic solutions. And compared to PIC codes on unstructured meshes, which have also been used for their flexibility in handling complex geometries but whose performance suffers from issues associated with data locality and indirect data access patterns, PIC codes on multi-block structured meshes may offer the best compromise for capturing complex geometries while also maintaining solution accuracy and computational efficiency.« less

  15. An electrostatic Particle-In-Cell code on multi-block structured meshes

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

    Meierbachtol, Collin S.; Svyatskiy, Daniil; Delzanno, Gian Luca

    We present an electrostatic Particle-In-Cell (PIC) code on multi-block, locally structured, curvilinear meshes called Curvilinear PIC (CPIC). Multi-block meshes are essential to capture complex geometries accurately and with good mesh quality, something that would not be possible with single-block structured meshes that are often used in PIC and for which CPIC was initially developed. In spite of the structured nature of the individual blocks, multi-block meshes resemble unstructured meshes in a global sense and introduce several new challenges, such as the presence of discontinuities in the mesh properties and coordinate orientation changes across adjacent blocks, and polyjunction points where anmore » arbitrary number of blocks meet. In CPIC, these challenges have been met by an approach that features: (1) a curvilinear formulation of the PIC method: each mesh block is mapped from the physical space, where the mesh is curvilinear and arbitrarily distorted, to the logical space, where the mesh is uniform and Cartesian on the unit cube; (2) a mimetic discretization of Poisson's equation suitable for multi-block meshes; and (3) a hybrid (logical-space position/physical-space velocity), asynchronous particle mover that mitigates the performance degradation created by the necessity to track particles as they move across blocks. The numerical accuracy of CPIC was verified using two standard plasma–material interaction tests, which demonstrate good agreement with the corresponding analytic solutions. And compared to PIC codes on unstructured meshes, which have also been used for their flexibility in handling complex geometries but whose performance suffers from issues associated with data locality and indirect data access patterns, PIC codes on multi-block structured meshes may offer the best compromise for capturing complex geometries while also maintaining solution accuracy and computational efficiency.« less

  16. Synthesis, characterization, and biocompatibility of alternating block polyurethanes based on PLA and PEG.

    PubMed

    Mei, Tingzhen; Zhu, Yonghe; Ma, Tongcui; He, Tao; Li, Linjing; Wei, Chiju; Xu, Kaitian

    2014-09-01

    A series of alternating block polyurethanes (abbreviated as PULA-alt-PEG) and random block polyurethanes (abbreviated as PULA-ran-PEG) based on poly(L-lactic acid) (PLA) and poly(ethylene glycol) (PEG) were synthesized. The differences of PULA-alt/ran-PEG chemical structure, molecular weight, distribution, thermal properties, mechanical properties and static contact angle were systematically investigated. The PULA-alt/ran-PEG polyurethanes exhibited low T(g) (-47.3 ∼ -34.4°C), wide mechanical properties (stress σ(t): 4.6-32.6 MPa, modulus E: 11.4-323.9 MPa and strain ε: 468-1530%) and low water contact angle (35.4-51.4°). Scanning electron microscope (SEM) observation showed that PULA-alt-PEG film displays rougher and more patterned surface morphology than PULA-ran-PEG does, due to more regular structures of PULA-alt-PEG. Hydrolytic degradation shows that degradation rate of random block polyurethane series PULA-ran-PEG is higher than the alternating counterpart PULA-alt-PEG. PLA segment degradation is faster than urethane linkage and PEG segment almost does not degrade in the buffer solution. Platelet adhesion study showed that all the polyurethanes possess excellent hemocompatibility. The cell culture assay revealed that PULA-alt/ran-PEG polyurethanes were cell inert and unfavorable for the attachment of rat glial cell due to the hydrophilic characters of the materials. © 2013 Wiley Periodicals, Inc.

  17. Sonoanatomy relevant for ultrasound-guided central neuraxial blocks via the paramedian approach in the lumbar region

    PubMed Central

    Karmakar, M K; Li, X; Kwok, W H; Ho, A M-H; Ngan Kee, W D

    2012-01-01

    Objectives The use of ultrasound to guide peripheral nerve blocks is now a well-established technique in regional anaesthesia. However, despite reports of ultrasound guided epidural access via the paramedian approach, there are limited data on the use of ultrasound for central neuraxial blocks, which may be due to a poor understanding of spinal sonoanatomy. The aim of this study was to define the sonoanatomy of the lumbar spine relevant for central neuraxial blocks via the paramedian approach. Methods The sonoanatomy of the lumbar spine relevant for central neuraxial blocks via the paramedian approach was defined using a “water-based spine phantom”, young volunteers and anatomical slices rendered from the Visible Human Project data set. Results The water-based spine phantom was a simple model to study the sonoanatomy of the osseous elements of the lumbar spine. Each osseous element of the lumbar spine, in the spine phantom, produced a “signature pattern” on the paramedian sagittal scans, which was comparable to its sonographic appearance in vivo. In the volunteers, despite the narrow acoustic window, the ultrasound visibility of the neuraxial structures at the L3/L4 and L4/L5 lumbar intervertebral spaces was good, and we were able to delineate the sonoanatomy relevant for ultrasound-guided central neuraxial blocks via the paramedian approach. Conclusion Using a simple water-based spine phantom, volunteer scans and anatomical slices from the Visible Human Project (cadaver) we have described the sonoanatomy relevant for ultrasound-guided central neuraxial blocks via the paramedian approach in the lumbar region. PMID:22010025

  18. A Theoretically Informed Model for the Rheology of Entangled Block Copolymer Nanocomposites

    NASA Astrophysics Data System (ADS)

    Su, Yongrui; Ramirez-Hernandez, Abelardo; Peters, Brandon; de Pablo, Juan J.

    2014-03-01

    The addition of nanoparticles to block copolymer systems has been shown to have important effects on their equilibrium structure and properties. Less is known about the non-equilibrium behavior of block polymer nanocomposites. A new particle-based, theoretically informed coarse-grained model for multicomponent nanocomposites is proposed to examine the effects of nanoparticles on the rheology of entangled block copolymer melts. Entanglements are treated at the two-molecule level, through slip-springs that couple the dynamics of neighboring pairs of chains. The inclusion of slip-springs changes the polymer dynamics from unentangled to entangled. The nanoparticles are functionalized with short polymer chains that can entangle with the copolymers. We study the nonlinear rheology of the resulting nanocomposites under shear flow with a dissipative particle dynamics (DPD) thermostat.

  19. Vibration Analysis of Beam and Block Precast Slab System due to Human Vibrations

    NASA Astrophysics Data System (ADS)

    Chik, T. N. T.; Kamil, M. R. H.; Yusoff, N. A.

    2018-04-01

    Beam and block precast slabs system are very efficient which generally give maximum structural performance where their voids based on the design of the unit soffit block allow a significant reduction of the whole slab self-weight. Initially for some combinations of components or the joint connection of the structural slab, this structural system may be susceptible to excessive vibrations that could effects the performance and also serviceability. Dynamic forces are excited from people walking and jumping which produced vibrations to the slab system in the buildings. Few studies concluded that human induced vibration on precast slabs system may be harmful to structural performance and mitigate the human comfort level. This study will investigate the vibration analysis of beam and block precast slab by using finite element method at the school building. Human activities which are excited from jumping and walking will induce the vibrations signal to the building. Laser Doppler Vibrometer (LDV) was used to measure the dynamic responses of slab towards the vibration sources. Five different points were assigned specifically where each of location will determine the behaviour of the entire slabs. The finite element analyses were developed in ABAQUS software and the data was further processed in MATLAB ModalV to assess the vibration criteria. The results indicated that the beam and block precast systems adequate enough to the vibration serviceability and human comfort criteria. The overall vibration level obtained was fell under VC-E curve which it is generally under the maximum permissible level of vibrations. The vibration level on the slab is acceptable within the limit that have been used by Gordon.

  20. Effect of Thermal and Chemical Treatment on the Microstructural, Mechanical and Machining Performance of W319 Al-Si-Cu Cast Alloy Engine Blocks and Directionally Solidified Machinability Test Blocks

    NASA Astrophysics Data System (ADS)

    Szablewski, Daniel

    The research presented in this work is focused on making a link between casting microstructural, mechanical and machining properties for 319 Al-Si sand cast components. In order to achieve this, a unique Machinability Test Block (MTB) is designed to simulate the Nemak V6 Al-Si engine block solidification behavior. This MTB is then utilized to cast structures with in-situ nano-alumina particle master alloy additions that are Mg based, as well as independent in-situ Mg additions, and Sr additions to the MTB. The Universal Metallurgical Simulator and Analyzer (UMSA) Technology Platform is utilized for characterization of each cast structure at different Secondary Dendrite Arm Spacing (SDAS) levels. The rapid quench method and Jominy testing is used to assess the capability of the nano-alumina master alloy to modify the microstructure at different SDAS levels. Mechanical property assessment of the MTB is done at different SDAS levels on cast structures with master alloy additions described above. Weibull and Quality Index statistical analysis tools are then utilized to assess the mechanical properties. The MTB is also used to study single pass high speed face milling and bi-metallic cutting operations where the Al-Si hypoeutectic structure is combined with hypereutectoid Al-Si liners and cast iron cylinder liners. These studies are utilized to aid the implementation of Al-Si liners into the Nemak V6 engine block and bi-metallic cutting of the head decks. Machining behavior is also quantified for the investigated microstructures, and the Silicon Modification Level (SiML) is utilized for microstructural analysis as it relates to the machining behavior.

  1. Computational strategies for the automated design of RNA nanoscale structures from building blocks using NanoTiler.

    PubMed

    Bindewald, Eckart; Grunewald, Calvin; Boyle, Brett; O'Connor, Mary; Shapiro, Bruce A

    2008-10-01

    One approach to designing RNA nanoscale structures is to use known RNA structural motifs such as junctions, kissing loops or bulges and to construct a molecular model by connecting these building blocks with helical struts. We previously developed an algorithm for detecting internal loops, junctions and kissing loops in RNA structures. Here we present algorithms for automating or assisting many of the steps that are involved in creating RNA structures from building blocks: (1) assembling building blocks into nanostructures using either a combinatorial search or constraint satisfaction; (2) optimizing RNA 3D ring structures to improve ring closure; (3) sequence optimisation; (4) creating a unique non-degenerate RNA topology descriptor. This effectively creates a computational pipeline for generating molecular models of RNA nanostructures and more specifically RNA ring structures with optimized sequences from RNA building blocks. We show several examples of how the algorithms can be utilized to generate RNA tecto-shapes.

  2. Computational strategies for the automated design of RNA nanoscale structures from building blocks using NanoTiler☆

    PubMed Central

    Bindewald, Eckart; Grunewald, Calvin; Boyle, Brett; O’Connor, Mary; Shapiro, Bruce A.

    2013-01-01

    One approach to designing RNA nanoscale structures is to use known RNA structural motifs such as junctions, kissing loops or bulges and to construct a molecular model by connecting these building blocks with helical struts. We previously developed an algorithm for detecting internal loops, junctions and kissing loops in RNA structures. Here we present algorithms for automating or assisting many of the steps that are involved in creating RNA structures from building blocks: (1) assembling building blocks into nanostructures using either a combinatorial search or constraint satisfaction; (2) optimizing RNA 3D ring structures to improve ring closure; (3) sequence optimisation; (4) creating a unique non-degenerate RNA topology descriptor. This effectively creates a computational pipeline for generating molecular models of RNA nanostructures and more specifically RNA ring structures with optimized sequences from RNA building blocks. We show several examples of how the algorithms can be utilized to generate RNA tecto-shapes. PMID:18838281

  3. Nanoporous polymeric nanofibers based on selectively etched PS-b-PDMS block copolymers.

    PubMed

    Demirel, Gokcen B; Buyukserin, Fatih; Morris, Michael A; Demirel, Gokhan

    2012-01-01

    One-dimensional nanoporous polymeric nanofibers have been fabricated within an anodic aluminum oxide (AAO) membrane by a facile approach based on selective etching of poly(dimethylsiloxane) (PDMS) domains in polystyrene-block-poly(dimethylsiloxane) (PS-b-PDMS) block copolymers that had been formed within the AAO template. It was observed that prior to etching, the well-ordered PS-b-PDMS nanofibers are solid and do not have any porosity. The postetched PS nanofibers, on the other hand, had a highly porous structure having about 20-50 nm pore size. The nanoporous polymeric fibers were also employed as a drug carrier for the native, continuous, and pulsatile drug release using Rhodamine B (RB) as a model drug. These studies showed that enhanced drug release and tunable drug dosage can be achieved by using ultrasound irradiation. © 2011 American Chemical Society

  4. Hybrid Silicon-Based Organic/Inorganic Block Copolymers with Sol-Gel Active Moieties: Synthetic Advances, Self-Assembly and Applications in Biomedicine and Materials Science.

    PubMed

    Czarnecki, Sebastian; Bertin, Annabelle

    2018-03-07

    Hybrid silicon-based organic/inorganic (multi)block copolymers are promising polymeric precursors to create robust nano-objects and nanomaterials due to their sol-gel active moieties via self-assembly in solution or in bulk. Such nano-objects and nanomaterials have great potential in biomedicine as nanocarriers or scaffolds for bone regeneration as well as in materials science as Pickering emulsifiers, photonic crystals or coatings/films with antibiofouling, antibacterial or water- and oil-repellent properties. Thus, this Review outlines recent synthetic efforts in the preparation of these hybrid inorganic/organic block copolymers, gives an overview of their self-assembled structures and finally presents recent examples of their use in the biomedical field and material science. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. In Situ Resource-Based Lunar and Martian Habitat Structures Development at NASA/MSFC

    NASA Technical Reports Server (NTRS)

    Bodiford, Melanie P.; Fiske, Michael R.; McGregory, Walter; Pope, Regina D.

    2005-01-01

    As the nation prepares to return to the Moon and subsequently to Mars, it is apparent that the viability of long duration visits with appropriate radiation shielding/crew protection, hinges on the development of habitat structures, preferably in advance of a manned landing, and preferably utilizing in-situ resources. A relatively large number of habitat structure configurations can be developed from a relatively small set of in-situ resource-based construction products, including, blocks, raw regolith, reinforced concrete, and glass products. A much larger group of habitat designs can be developed when "imported" material are brought from Earth, including thin films and liners, and foldable, or expandable metal structures. These, and other technologies have been identified, and subjected to a rigorous trade study evaluation with respect to exploration and other performance criteria. In this paper, results of this trade study will be presented, as well as various habitat structure design concepts and concepts for construction automation. Results of initial tests aimed at concrete, block and glass production using Lunar regolith simulants will also be presented. Key issues and concerns will be discussed, as well as design concepts for a Lunar environment testbed to be developed at MSFC's Microgravity Development Laboratory. (MDL).

  6. In-situ Resource-based Lunar and Martian Habitat Structures Development at NASA/MSFC

    NASA Technical Reports Server (NTRS)

    Bodiford, Melanie P.; Burks, Kevin H.; Fiske, Michael R.; Strong, Janet D.; McGregor, Walter

    2005-01-01

    As the nation prepares to return to the Moon and subsequently to Mars, it is apparent that the viability of long duration visits with appropriate radiation shielding/crew protection, hinges on the development of habitat structures, preferably in advance of a manned landing, and preferably utilizing in-situ resources. A relatively large number of habitat structure configurations can be developed from a relatively small set of in-situ resource-based construction products, including, blocks, raw regolith, reinforced concrete, and glass products. A much larger group of habitat designs can be developed when "imported" material are brought from Earth, including thin films and liners, and foldable, or expandable metal structures. These, and other technologies have been identified, and subjected to a rigorous trade study evaluation with respect to exploration and other performance criteria. In this paper, results of this trade study will be presented, as well as various habitat structure design concepts and concepts for construction automation. Results of initial tests aimed at concrete, block and glass production using Lunar regolith simulants will also be presented. Key issues and concerns will be discussed, as well as design concepts for a Lunar environment testbed to be developed at MSFC's Microgravity Development Laboratory (MDL).

  7. The StreamCat Dataset: Accumulated Attributes for NHDPlusV2 Catchments (Version 2.1) for the Conterminous United States: 2010 US Census Housing Unit and Population Density

    EPA Pesticide Factsheets

    This dataset represents the population and housing unit density within individual, local NHDPlusV2 catchments and upstream, contributing watersheds based on 2010 US Census data. Densities are calculated for every block group and watershed averages are calculated for every local NHDPlusV2 catchment(see Data Sources for links to NHDPlusV2 data and Census Data). This data set is derived from The TIGER/Line Files and related database (.dbf) files for the conterminous USA. It was downloaded as Block Group-Level Census 2010 SF1 Data in File Geodatabase Format (ArcGIS version 10.0). The landscape raster (LR) was produced based on the data compiled from the questions asked of all people and about every housing unit. The (block-group population / block group area) and (block-group housing units / block group area) were summarized by local catchment and by watershed to produce local catchment-level and watershed-level metrics as a continuous data type (see Data Structure and Attribute Information for a description). Using a riparian buffer(see Process Steps), statistics were generated for areas within each catchment that are within 100 meters of the stream reach in an attempt to evaluate for the riparian zone.

  8. Multi-level bandwidth efficient block modulation codes

    NASA Technical Reports Server (NTRS)

    Lin, Shu

    1989-01-01

    The multilevel technique is investigated for combining block coding and modulation. There are four parts. In the first part, a formulation is presented for signal sets on which modulation codes are to be constructed. Distance measures on a signal set are defined and their properties are developed. In the second part, a general formulation is presented for multilevel modulation codes in terms of component codes with appropriate Euclidean distances. The distance properties, Euclidean weight distribution and linear structure of multilevel modulation codes are investigated. In the third part, several specific methods for constructing multilevel block modulation codes with interdependency among component codes are proposed. Given a multilevel block modulation code C with no interdependency among the binary component codes, the proposed methods give a multilevel block modulation code C which has the same rate as C, a minimum squared Euclidean distance not less than that of code C, a trellis diagram with the same number of states as that of C and a smaller number of nearest neighbor codewords than that of C. In the last part, error performance of block modulation codes is analyzed for an AWGN channel based on soft-decision maximum likelihood decoding. Error probabilities of some specific codes are evaluated based on their Euclidean weight distributions and simulation results.

  9. Superalloy Lattice Block Structures

    NASA Technical Reports Server (NTRS)

    Nathal, M. V.; Whittenberger, J. D.; Hebsur, M. G.; Kantzos, P. T.; Krause, D. L.

    2004-01-01

    Initial investigations of investment cast superalloy lattice block suggest that this technology will yield a low cost approach to utilize the high temperature strength and environmental resistance of superalloys in lightweight, damage tolerant structural configurations. Work to date has demonstrated that relatively large superalloy lattice block panels can be successfully investment cast from both IN-718 and Mar-M247. These castings exhibited mechanical properties consistent with the strength of the same superalloys measured from more conventional castings. The lattice block structure also accommodates significant deformation without failure, and is defect tolerant in fatigue. The potential of lattice block structures opens new opportunities for the use of superalloys in future generations of aircraft applications that demand strength and environmental resistance at elevated temperatures along with low weight.

  10. Block and Gradient Copoly(2-oxazoline) Micelles: Strikingly Different on the Inside.

    PubMed

    Filippov, Sergey K; Verbraeken, Bart; Konarev, Petr V; Svergun, Dmitri I; Angelov, Borislav; Vishnevetskaya, Natalya S; Papadakis, Christine M; Rogers, Sarah; Radulescu, Aurel; Courtin, Tim; Martins, José C; Starovoytova, Larisa; Hruby, Martin; Stepanek, Petr; Kravchenko, Vitaly S; Potemkin, Igor I; Hoogenboom, Richard

    2017-08-17

    Herein, we provide a direct proof for differences in the micellar structure of amphiphilic diblock and gradient copolymers, thereby unambiguously demonstrating the influence of monomer distribution along the polymer chains on the micellization behavior. The internal structure of amphiphilic block and gradient co poly(2-oxazolines) based on the hydrophilic poly(2-methyl-2-oxazoline) (PMeOx) and the hydrophobic poly(2-phenyl-2-oxazoline) (PPhOx) was studied in water and water-ethanol mixtures by small-angle X-ray scattering (SAXS), small-angle neutron scattering (SANS), static and dynamic light scattering (SLS/DLS), and 1 H NMR spectroscopy. Contrast matching SANS experiments revealed that block copolymers form micelles with a uniform density profile of the core. In contrast to popular assumption, the outer part of the core of the gradient copolymer micelles has a distinctly higher density than the middle of the core. We attribute the latter finding to back-folding of chains resulting from hydrophilic-hydrophobic interactions, leading to a new type of micelles that we refer to as micelles with a "bitterball-core" structure.

  11. Synthesis and studies of polypeptide materials: Self-assembled block copolypeptide amphiphiles, DNA-condensing block copolypeptides and membrane-interactive random copolypeptides

    NASA Astrophysics Data System (ADS)

    Wyrsta, Michael Dmytro

    A new class of transition metal initiators for the controlled polymerization of alpha-aminoacid-N-carboxyanhydrides (alpha-NCAs), has been developed by Deming et al. This discovery has allowed for the synthesis of well-defined "protein-like" polymers. Using this chemistry we have made distinct block/random copolypeptides for biomedical applications. Drug delivery, gene delivery, and antimicrobial polymers were the focus of our research efforts. The motivation for the synthesis and study of synthetic polypeptide based materials comes from proteins. Natural proteins are able to adopt a staggeringly large amount of uniquely well-defined folded structures. These structures account for the diversity in properties of proteins. As catalysts (enzymes) natural proteins perform some of the most difficult chemistry with ease and precision at ambient pressures and temperatures. They also exhibit incredible structural properties that directly result from formation of complex hierarchical assemblies. Self-assembling block copolymers were synthesized with various compositions and architectures. In general, di- and tri-block amphiphiles were studied for their self-assembling properties. Both spherical and tubular vesicles were found to assemble from di- and tri-block amphiphiles, respectively. In addition to self-assembly, pH responsiveness was engineered into these amphiphiles by the incorporation of basic residues (lysine) into the hydrophobic block. Another form of self-assembly studied was the condensation of DNA using cationic block copolymers. It was found that cationic block copolymers could condense DNA into compact, ordered, water-soluble aggregates on the nanoscale. These aggregates sufficiently protected DNA from nucleases and yet were susceptible to proteases. These studies form the basis of a gene delivery platform. The ease with which NCAs are polymerized renders them completely amenable to parallel synthetic methods. We have employed this technique to discover new antimicrobial polypeptides. The polymers studied were themselves the antimicrobial agent, not a self-assembled aggregate that contained antibiotics. It was found that powerful antibacterial polymers could be readily prepared with simple binary compositions. Antibacterial activity was sensitive to copolymer composition, bacterial cell-wall type, and insensitive to chain length (within reason).

  12. Polyacrylonitrile block copolymers for the preparation of a thin carbon coating around TiO2 nanorods for advanced lithium-ion batteries.

    PubMed

    Oschmann, Bernd; Bresser, Dominic; Tahir, Muhammad Nawaz; Fischer, Karl; Tremel, Wolfgang; Passerini, Stefano; Zentel, Rudolf

    2013-11-01

    Herein, a new method for the realization of a thin and homogenous carbonaceous particle coating, made by carbonizing RAFT polymerization derived block copolymers anchored on anatase TiO2 nanorods, is presented. These block copolymers consist of a short anchor block (based on dopamine) and a long, easily graphitizable block of polyacrylonitrile. The grafting of such block copolymers to TiO2 nanorods creates a polymer shell, which can be visualized by atomic force microscopy (AFM). Thermal treatment at 700 °C converts the polyacrylonitrile block to partially graphitic structures (as determined by Raman spectroscopy), establishing a thin carbon coating (as determined by transmission electron microscopy, TEM, analysis). The carbon-coated TiO2 nanorods show improved electrochemical performance in terms of achievable specific capacity and, particularly, long-term cycling stability by reducing the average capacity fading per cycle from 0.252 mAh g(-1) to only 0.075 mAh g(-1) . © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Atmospheric Blocking and Atlantic Multi-Decadal Ocean Variability

    NASA Technical Reports Server (NTRS)

    Haekkinen, Sirpa; Rhines, Peter B.; Worthlen, Denise L.

    2011-01-01

    Based on the 20th century atmospheric reanalysis, winters with more frequent blocking, in a band of blocked latitudes from Greenland to Western Europe, are found to persist over several decades and correspond to a warm North Atlantic Ocean, in-phase with Atlantic multi-decadal ocean variability. Atmospheric blocking over the northern North Atlantic, which involves isolation of large regions of air from the westerly circulation for 5 days or more, influences fundamentally the ocean circulation and upper ocean properties by impacting wind patterns. Winters with clusters of more frequent blocking between Greenland and western Europe correspond to a warmer, more saline subpolar ocean. The correspondence between blocked westerly winds and warm ocean holds in recent decadal episodes (especially, 1996-2010). It also describes much longer-timescale Atlantic multidecadal ocean variability (AMV), including the extreme, pre-greenhouse-gas, northern warming of the 1930s-1960s. The space-time structure of the wind forcing associated with a blocked regime leads to weaker ocean gyres and weaker heat-exchange, both of which contribute to the warm phase of AMV.

  14. Formation of cage-like particles by poly(amino acid)-based block copolymers in aqueous solution.

    PubMed Central

    Cudd, A; Bhogal, M; O'Mullane, J; Goddard, P

    1991-01-01

    When dissolved in N,N-dimethylformamide and then dialyzed against phosphate-buffered saline, A-B-A block copolymers composed of poly [N5-(2-hydroxyethyl)-L-glutamine]-block-poly(gamma-benzyl-L-glutamate)- block-poly [N5-(2-hydroxyethyl)-L-glutamine] form particles. The particles are cage-like structures with average diameters of 300 nm (average polydispersity, 0.3-0.5). They are stable in aqueous solution at 4 degrees C for up to 3 weeks, at which time flocculation becomes apparent. Negative staining and freeze-fracture electron microscopy suggest that cage-like particles are formed by selective association of segregated micelle populations. A model of particle formation is presented in which B blocks form micelles in dimethylformamide. On dialysis against an aqueous solution, the extended A blocks then associate intermolecularly to form rod-shaped micelles, which connect the B block micelles. The result is a meshed cage-like particle. The implications of these observations on the aggregation behavior of polymeric surfactants in dilute solution are discussed. Images PMID:11607245

  15. Block versus Random Amphiphilic Glycopolymer Nanopaticles as Glucose-Responsive Vehicles.

    PubMed

    Guo, Qianqian; Zhang, Tianqi; An, Jinxia; Wu, Zhongming; Zhao, Yu; Dai, Xiaomei; Zhang, Xinge; Li, Chaoxing

    2015-10-12

    To explore the effect of polymer structure on their self-assembled aggregates and their unique characteristics, this study was devoted to developing a series of amphiphilic block and random phenylboronic acid-based glycopolymers by RAFT polymerization. The amphiphilic glycopolymers were successfully self-assembled into spherically shaped nanoparticles with narrow size distribution in aqueous solution. For block and random copolymers with similar monomer compositions, block copolymer nanoparticles exhibited a more regular transmittance change with the increasing glucose level, while a more evident variation of size and quicker decreasing tendency in I/I0 behavior in different glucose media were observed for random copolymer nanoparticles. Cell viability of all the polymer nanoparticles investigated by MTT assay was higher than 80%, indicating that both block and random copolymers had good cytocompatibility. Insulin could be encapsulated into both nanoparticles, and insulin release rate for random glycopolymer was slightly quicker than that for the block ones. We speculate that different chain conformations between block and random glycopolymers play an important role in self-assembled nanoaggregates and underlying glucose-sensitive behavior.

  16. NUCLEAR REACTORS

    DOEpatents

    Long, E.; Ashley, J.W.

    1958-12-16

    A graphite moderator structure is described for a gas-cooled nuclear reactor having a vertical orlentation wherein the structure is physically stable with regard to dlmensional changes due to Wigner growth properties of the graphite, and leakage of coolant gas along spaces in the structure is reduced. The structure is comprised of stacks of unlform right prismatic graphite blocks positioned in layers extending in the direction of the lengths of the blocks, the adjacent end faces of the blocks being separated by pairs of tiles. The blocks and tiles have central bores which are in alignment when assembled and are provided with cooperatlng keys and keyways for physical stability.

  17. Design development of graphite primary structures enables SSTO success

    NASA Astrophysics Data System (ADS)

    Biagiotti, V. A.; Yahiro, J. S.; Suh, Daniel E.; Hodges, Eric R.; Prior, Donald J.

    1997-01-01

    This paper describes the development of a graphite composite wing and a graphite composite intertank primary structure for application toward Single-Stage to Orbit space vehicles such as those under development in NASA's X-33/Reusable Launch Vehicle (RLV) Program. The trade study and designs are based on a Rockwell vertical take-off and horizontal landing (VTHL) wing-body RLV vehicle. Northrop Grumman's approach using a building block development technique is described. Composite Graphite/Bismaleimide (Gr/BMI) material characterization test results are presented. Unique intertank and wing composite subcomponent test article designs are described and test results to date are presented. Wing and intertank Full Scale Section Test Article (FSTA) objectives and designs are outlined. Trade studies, supporting building block testing, and FSTA demonstrations combine to develop graphite primary structure composite technology that enables developing X-33/RLV design programs to meet critical SSTO structural weight and operations performance criteria.

  18. Hollow Block Copolymer Nanoparticles through a Spontaneous One-Step Structural Reorganization

    PubMed Central

    Petzetakis, Nikos; Robin, Mathew P.; Patterson, Joseph P.; Kelley, Elizabeth G.; Cotanda, Pepa; Bomans, Paul H. H.; Sommerdijk, Nico A. J. M.; Dove, Andrew P.; Epps, Thomas H.; O'Reilly, Rachel K.

    2013-01-01

    The spontaneous one-step synthesis of hollow nanocages and nanotubes from spherical and cylindrical micelles based on poly(acrylic acid)-b-polylactide (P(AA)-b-P(LA)) block copolymers (BCPs) has been achieved. This structural reorganization, which occurs simply upon drying of the samples, was elucidated by transmission electron microscopy (TEM) and atomic force microscopy (AFM). We show that it was necessary to use stain-free imaging to examine these nanoscale assemblies, as the hollow nature of the particles was obscured by application of a heavy metal stain. Additionally, the internal topology of the P(AA)-b-P(LA) particles could be tuned by manipulating the drying conditions to give solid or compartmentalized structures. Upon re-suspension, these reorganized nanoparticles retain their hollow structure and can be display significantly enhanced loading of a hydrophobic dye compared to the original cylinders. PMID:23391297

  19. M13 Bacteriophage-Based Self-Assembly Structures and Their Functional Capabilities.

    PubMed

    Moon, Jong-Sik; Kim, Won-Geun; Kim, Chuntae; Park, Geun-Tae; Heo, Jeong; Yoo, So Y; Oh, Jin-Woo

    2015-06-01

    Controlling the assembly of basic structural building blocks in a systematic and orderly fashion is an emerging issue in various areas of science and engineering such as physics, chemistry, material science, biological engineering, and electrical engineering. The self-assembly technique, among many other kinds of ordering techniques, has several unique advantages and the M13 bacteriophage can be utilized as part of this technique. The M13 bacteriophage (Phage) can easily be modified genetically and chemically to demonstrate specific functions. This allows for its use as a template to determine the homogeneous distribution and percolated network structures of inorganic nanostructures under ambient conditions. Inexpensive and environmentally friendly synthesis can be achieved by using the M13 bacteriophage as a novel functional building block. Here, we discuss recent advances in the application of M13 bacteriophage self-assembly structures and the future of this technology.

  20. M13 Bacteriophage-Based Self-Assembly Structures and Their Functional Capabilities

    PubMed Central

    Moon, Jong-Sik; Kim, Won-Geun; Kim, Chuntae; Park, Geun-Tae; Heo, Jeong; Yoo, So Y; Oh, Jin-Woo

    2015-01-01

    Controlling the assembly of basic structural building blocks in a systematic and orderly fashion is an emerging issue in various areas of science and engineering such as physics, chemistry, material science, biological engineering, and electrical engineering. The self-assembly technique, among many other kinds of ordering techniques, has several unique advantages and the M13 bacteriophage can be utilized as part of this technique. The M13 bacteriophage (Phage) can easily be modified genetically and chemically to demonstrate specific functions. This allows for its use as a template to determine the homogeneous distribution and percolated network structures of inorganic nanostructures under ambient conditions. Inexpensive and environmentally friendly synthesis can be achieved by using the M13 bacteriophage as a novel functional building block. Here, we discuss recent advances in the application of M13 bacteriophage self-assembly structures and the future of this technology. PMID:26146494

  1. Characterizing the Three-Dimensional Structure of Block Copolymers via Sequential Infiltration Synthesis and Scanning Transmission Electron Tomography

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

    Segal-Peretz, Tamar; Winterstein, Jonathan; Doxastakis, Manolis

    Understanding and controlling the three-dimensional structure of block copolymer (BCP) thin films is critical for utilizing these materials for sub-20 nm nanopatterning in semiconductor devices, as well as in membranes and solar cell applications. Combining an atomic layer deposition (ALD) based technique for enhancing the contrast of BCPs in transmission electron microscopy (TEM) together with scanning TEM (STEM) tomography reveals and characterizes the three-dimensional structures of poly(styrene-block-methyl methacrylate) (PS-b-PMMA) thin films with great clarity. Sequential infiltration synthesis (SIS), a block-selective technique for growing inorganic materials in BCPs films in ALD, and an emerging tool for enhancing the etch contrast ofmore » BCPs, was harnessed to significantly enhance the high-angle scattering from the polar domains of BCP films in the TEM. The power of combining SIS and STEM tomography for three dimensional (3D) characterization of BCPs films was demonstrated with the following cases: self-assembled cylindrical, lamellar, and spherical PS-PMMA thin films. In all cases, STEM tomography has revealed 3D structures that were hidden underneath the surface, including: 1) the 3D structure of defects in cylindrical and lamellar phases, 2) non-perpendicular 3D surface of grain boundaries in the cylindrical phase, and 3) the 3D arrangement of spheres in body centered cubic (BCC) and hexagonal closed pack (HCP) morphologies in the spherical phase. The 3D data of the spherical morphologies was compared to coarse-grained simulations and assisted in validating the simulations’ parameters. STEM tomography of SIS-treated BCP films enables the characterization of the exact structure used for pattern transfer, and can lead to better understating of the physics which is utilized in BCP lithography.« less

  2. An O([Formula: see text]) algorithm for sorting signed genomes by reversals, transpositions, transreversals and block-interchanges.

    PubMed

    Yu, Shuzhi; Hao, Fanchang; Leong, Hon Wai

    2016-02-01

    We consider the problem of sorting signed permutations by reversals, transpositions, transreversals, and block-interchanges. The problem arises in the study of species evolution via large-scale genome rearrangement operations. Recently, Hao et al. gave a 2-approximation scheme called genome sorting by bridges (GSB) for solving this problem. Their result extended and unified the results of (i) He and Chen - a 2-approximation algorithm allowing reversals, transpositions, and block-interchanges (by also allowing transversals) and (ii) Hartman and Sharan - a 1.5-approximation algorithm allowing reversals, transpositions, and transversals (by also allowing block-interchanges). The GSB result is based on introduction of three bridge structures in the breakpoint graph, the L-bridge, T-bridge, and X-bridge that models goodreversal, transposition/transreversal, and block-interchange, respectively. However, the paper by Hao et al. focused on proving the 2-approximation GSB scheme and only mention a straightforward [Formula: see text] algorithm. In this paper, we give an [Formula: see text] algorithm for implementing the GSB scheme. The key idea behind our faster GSB algorithm is to represent cycles in the breakpoint graph by their canonical sequences, which greatly simplifies the search for these bridge structures. We also give some comparison results (running time and computed distances) against the original GSB implementation.

  3. Nano-structured polymer composites and process for preparing same

    DOEpatents

    Hillmyer, Marc; Chen, Liang

    2013-04-16

    A process for preparing a polymer composite that includes reacting (a) a multi-functional monomer and (b) a block copolymer comprising (i) a first block and (ii) a second block that includes a functional group capable of reacting with the multi-functional monomer, to form a crosslinked, nano-structured, bi-continuous composite. The composite includes a continuous matrix phase and a second continuous phase comprising the first block of the block copolymer.

  4. Transport and Depositional Model for Large Country Rock Blocks Within the Searchlight Pluton, Southern Nevada

    NASA Astrophysics Data System (ADS)

    Perrault, D. S.; Furbish, D. J.; Miller, C. F.

    2006-05-01

    Searchlight pluton, a steeply tilted, 10 km thick Miocene intrusion in the Colorado River Extensional Corridor, exposes a zone with abundant, 5-400 m long blocks of Proterozoic gneiss. Blocks are present within a pair of subparallel horizons that make up a 2 km-thick zone and extend about 6 km laterally away from the pluton's north margin slightly oblique to the initially subhorizontal boundary between the pluton's middle unit (granite) and lower unit (qtz monzonite). Blocks are a variety of Precambrian metasedimentary gneisses, granitic gneisses, and mylonites. Blocks are commonly polylithologic and well foliated, with long and intermediate dimensions parallel to both their own foliation and that of the granitic host. Their average aspect ratio is ~ 4:1. Blocks within these horizons are interpreted as stoped (detached country rock that experience gravity- induced displacement) based on several lines of evidence. First, the distribution and abundances of blocks are not consistent with an isolated panel of wall rock (screen). The zone is laterally discontinuous (local abundances vary from ~ 0-40 %); transects a gradational (cm-m scale) internal contact at a slightly oblique angle; and tapers away from the pluton's margin. Second, while block foliations are homoclinal and show fairly consistent attitudes from block to block, block foliations are discordant with wall rock foliations at the same stratigraphic level (adjacent north wall). Third, mush disturbance features such as schlieren and enhanced feldspar foliation beneath blocks suggest a downward compaction. We interpret the blocks to have been emplaced after wall collapse events. We are using scaled settling experiments to clarify how blocks move within viscous fluids and interact with crystal mushes. The experiments, involving tabular ceramic blocks with density ρ = 1.75-2.20 g cm-3 settling in shampoo (ρ = 1.02 g cm-3) with viscosity μ = 20.35 Pa s, are scaled to order-of-magnitude by the particle Reynolds number (Re ~ 10-2) based on a prototype spherical block of diameter ~ 50 m settling through a crystal free magma with the density (~ 2.25 g cm-3) and viscosity (~ 105 Pa s) of a granitic melt. With low Reynolds number settling, tabular blocks starting from arbitrary orientation tend to become aligned with their long dimension vertical. During alignment fluid shear is focused on the trailing part of the downward facing surface of the block, inducing a torque that tends to upright the block. Settling experiments also provide insights regarding how blocks might interact with mush/melt interfaces. Mushes at sufficiently high crystal content (>50%) stiffen rheologically. Stoped blocks settling on these interfaces may impart stresses that result in localized deformation of the mush (forming schlieren and/or compaction features). We moreover suggest that tabular blocks are deposited with their long axes horizontal at these interfaces; blocks with a geometry controlled by internal structures (e.g. foliation) would on average possess a subparallel alignment of both their geometric shape and internal structure. At sufficiently low Re, this realignment of a tabular block begins as it approaches a semi-rigid surface or interface and the leading fluid boundary layer interacts with the interface; the vertical speed of the block decreases and it begins to deflect and take on a lateral motion.

  5. An open-structure sound insulator against low-frequency and wide-band acoustic waves

    NASA Astrophysics Data System (ADS)

    Chen, Zhe; Fan, Li; Zhang, Shu-yi; Zhang, Hui; Li, Xiao-juan; Ding, Jin

    2015-10-01

    To block sound, i.e., the vibration of air, most insulators are based on sealed structures and prevent the flow of the air. In this research, an acoustic metamaterial adopting side structures, loops, and labyrinths, arranged along a main tube, is presented. By combining the accurately designed side structures, an extremely wide forbidden band with a low cut-off frequency of 80 Hz is produced, which demonstrates a powerful low-frequency and wide-band sound insulation ability. Moreover, by virtue of the bypass arrangement, the metamaterial is based on an open structure, and thus air flow is allowed while acoustic waves can be insulated.

  6. Parquet: Regions of areal plastic dislocations (on Venus)

    NASA Technical Reports Server (NTRS)

    Sukhanov, A. L.

    1986-01-01

    The extensive flat elevations of the Northern Hemisphere of Venus are covered with frequently intersecting lines of dislocations, resembling the outline of a giant parquet. In the internal sections of these regions we find grabens and regions of extension, and on the periphery lobe-shaped flow structures. The parquet was formed after the beginning of the formation of the lava plains, but covered by the youngest lava. These structures apparently arose partly because of the dragging of blocks of crust by the asthenospheric flows, and partly in the gravitational sliding of such heated blocks in the partial melting of their base. It is possible that these elevations occupy on Venus the place of the Earth's rift systems.

  7. New polytypes of LPSO structures in an Mg-Co-Y alloy

    NASA Astrophysics Data System (ADS)

    Jin, Q. Q.; Shao, X. H.; Hu, X. B.; Peng, Z. Z.; Ma, X. L.

    2017-01-01

    The magnesium alloys containing long-period stacking ordered (LPSO) structures exhibit excellent mechanical properties. Each LPSO structure is known to contain either AB‧C‧A or AB‧C building block and feature its own stacking sequences. By atomic-scale high-angle annular dark field scanning transmission electron microscopy, we find the co-existence of AB‧C‧A and AB‧C building block in a single LPSO structure of the as-cast Mg92Co2Y6 (at.%) alloy, leading to the formation of six new polytypes of the LPSO structures determined as 29H, 51R, 60H, 72R, 102R and 192R. The lattice parameter of each LPSO structure is derived as ? and ? (n presents the number of basal layers in a unit cell). The stacking sequences and the space groups of these newly identified LPSO structures are proposed based on the electron diffraction and atomic-scale aberration-corrected high-resolution images. A random distribution of Co/Y elements in the basal planes of AB‧C‧A and AB‧C structural units is also observed and discussed.

  8. Multistage Computerized Adaptive Testing with Uniform Item Exposure

    ERIC Educational Resources Information Center

    Edwards, Michael C.; Flora, David B.; Thissen, David

    2012-01-01

    This article describes a computerized adaptive test (CAT) based on the uniform item exposure multi-form structure (uMFS). The uMFS is a specialization of the multi-form structure (MFS) idea described by Armstrong, Jones, Berliner, and Pashley (1998). In an MFS CAT, the examinee first responds to a small fixed block of items. The items comprising…

  9. Policy in Practice: The Implementation of Structured English Immersion in Arizona

    ERIC Educational Resources Information Center

    Lillie, Karen E.; Markos, Amy; Estrella, Alexandria; Nguyen, Tracy; Trifiro, Anthony; Arias, M. Beatriz; Wiley, Terrence G.; Peer, Karisa; Perez, Karla

    2010-01-01

    This study examines the implementation and organization of the state mandated curriculum in the 4-hour SEI block in 18 K-12 classrooms in 5 different districts. We focus on the effects of grouping by language proficiency, the delivery of the structure-based ESL curriculum, the provision of resources and limiting of access to grade-level…

  10. Materials taking a lesson from nature.

    PubMed

    Tian, Liangfei; Croisier, Emmanuel; Frauenrath, Holger

    2013-01-01

    Structural biomaterials with their often extraordinary properties and versatile functions are typically constructed from very limited sets of building blocks and types of supramolecular interactions. In this review we discuss how, inspired by nature's design principles for protein-based materials, oligopeptide-modified polymers can be used as a versatile toolbox to program nanostructure and hierarchical structure formation in synthetic materials.

  11. Large space erectable structures - building block structures study

    NASA Technical Reports Server (NTRS)

    Armstrong, W. H.; Skoumal, D. E.; Straayer, J. W.

    1977-01-01

    A modular planar truss structure and a long slender boom concept identified as building block approaches to construction of large spacecraft configurations are described. The concepts are compatible in weight and volume goals with the Space Transportation System, use standard structural units, and represent high on-orbit productivity in terms of structural area or beam length. Results of structural trade studies involving static and dynamic analyses of a single module and rigid body deployment analyses to assess kinetics and kinematics of automatic deployment of the building block modules are presented.

  12. Improved Tumor Targeting of Polymer-based Nanovesicles Using Polymer-Lipid Blends

    PubMed Central

    Cheng, Zhiliang; Elias, Drew R.; Kamat, Neha P.; Johnston, Eric D.; Poloukhtine, Andrei; Popik, Vladimir; Hammer, Daniel A.; Tsourkas, Andrew

    2011-01-01

    Block copolymer-based vesicles have recently garnered a great deal of interest as nanoplatforms for drug delivery and molecular imaging applications due to their unique structural properties. These nanovesicles have been shown to direct their cargo to disease sites either through enhanced permeability and retention or even more efficiently via active targeting. Here we show that the efficacy of nanovesicle targeting can be significantly improved when prepared from polymer-lipid blends compared with block copolymer alone. Polymer-lipid hybrid nanovesicles were produced from the aqueous co-assembly of the diblock copolymer, poly(ethylene oxide)-block-polybutadiene (PEO-PBD), and the phospholipid, hydrogenated soy phosphatidylcholine (HSPC). The PEG-based vesicles, 117 nm in diameter, were functionalized with either folic acid or anti-HER2/neu affibodies as targeting ligands to confer specificity for cancer cells. Our results revealed that nanovesicles prepared from polymer-lipid blends led to significant improvement in cell binding compared to nanovesicles prepared from block copolymer alone in both in vitro cell studies and murine tumor models. Therefore, it is envisioned that nanovesicles composed of polymer-lipid blends may constitute a preferred embodiment for targeted drug delivery and molecular imaging applications. PMID:21899335

  13. Guiding principles for peptide nanotechnology through directed discovery.

    PubMed

    Lampel, A; Ulijn, R V; Tuttle, T

    2018-05-21

    Life's diverse molecular functions are largely based on only a small number of highly conserved building blocks - the twenty canonical amino acids. These building blocks are chemically simple, but when they are organized in three-dimensional structures of tremendous complexity, new properties emerge. This review explores recent efforts in the directed discovery of functional nanoscale systems and materials based on these same amino acids, but that are not guided by copying or editing biological systems. The review summarises insights obtained using three complementary approaches of searching the sequence space to explore sequence-structure relationships for assembly, reactivity and complexation, namely: (i) strategic editing of short peptide sequences; (ii) computational approaches to predicting and comparing assembly behaviours; (iii) dynamic peptide libraries that explore the free energy landscape. These approaches give rise to guiding principles on controlling order/disorder, complexation and reactivity by peptide sequence design.

  14. Nearly Efficiency-Droop-Free AlGaN-Based Ultraviolet Light-Emitting Diodes with a Specifically Designed Superlattice p-Type Electron Blocking Layer for High Mg Doping Efficiency.

    PubMed

    Zhang, Zi-Hui; Huang Chen, Sung-Wen; Chu, Chunshuang; Tian, Kangkai; Fang, Mengqian; Zhang, Yonghui; Bi, Wengang; Kuo, Hao-Chung

    2018-04-24

    This work reports a nearly efficiency-droop-free AlGaN-based deep ultraviolet light-emitting diode (DUV LED) emitting in the peak wavelength of 270 nm. The DUV LED utilizes a specifically designed superlattice p-type electron blocking layer (p-EBL). The superlattice p-EBL enables a high hole concentration in the p-EBL which correspondingly increases the hole injection efficiency into the multiple quantum wells (MQWs). The enhanced hole concentration within the MQW region can more efficiently recombine with electrons in the way of favoring the radiative recombination, leading to a reduced electron leakage current level. As a result, the external quantum efficiency for the proposed DUV LED structure is increased by 100% and the nearly efficiency-droop-free DUV LED structure is obtained experimentally.

  15. Nearly Efficiency-Droop-Free AlGaN-Based Ultraviolet Light-Emitting Diodes with a Specifically Designed Superlattice p-Type Electron Blocking Layer for High Mg Doping Efficiency

    NASA Astrophysics Data System (ADS)

    Zhang, Zi-Hui; Huang Chen, Sung-Wen; Chu, Chunshuang; Tian, Kangkai; Fang, Mengqian; Zhang, Yonghui; Bi, Wengang; Kuo, Hao-Chung

    2018-04-01

    This work reports a nearly efficiency-droop-free AlGaN-based deep ultraviolet light-emitting diode (DUV LED) emitting in the peak wavelength of 270 nm. The DUV LED utilizes a specifically designed superlattice p-type electron blocking layer (p-EBL). The superlattice p-EBL enables a high hole concentration in the p-EBL which correspondingly increases the hole injection efficiency into the multiple quantum wells (MQWs). The enhanced hole concentration within the MQW region can more efficiently recombine with electrons in the way of favoring the radiative recombination, leading to a reduced electron leakage current level. As a result, the external quantum efficiency for the proposed DUV LED structure is increased by 100% and the nearly efficiency-droop-free DUV LED structure is obtained experimentally.

  16. A multi-block adaptive solving technique based on lattice Boltzmann method

    NASA Astrophysics Data System (ADS)

    Zhang, Yang; Xie, Jiahua; Li, Xiaoyue; Ma, Zhenghai; Zou, Jianfeng; Zheng, Yao

    2018-05-01

    In this paper, a CFD parallel adaptive algorithm is self-developed by combining the multi-block Lattice Boltzmann Method (LBM) with Adaptive Mesh Refinement (AMR). The mesh refinement criterion of this algorithm is based on the density, velocity and vortices of the flow field. The refined grid boundary is obtained by extending outward half a ghost cell from the coarse grid boundary, which makes the adaptive mesh more compact and the boundary treatment more convenient. Two numerical examples of the backward step flow separation and the unsteady flow around circular cylinder demonstrate the vortex structure of the cold flow field accurately and specifically.

  17. Finite Frequency Traveltime Tomography of Lithospheric and Upper Mantle Structures beneath the Cordillera-Craton Transition in Southwestern Canada

    NASA Astrophysics Data System (ADS)

    Chen, Y.; Gu, Y. J.; Hung, S. H.

    2014-12-01

    Based on finite-frequency theory and cross-correlation teleseismic relative traveltime data from the USArray, Canadian National Seismograph Network (CNSN) and Canadian Rockies and Alberta Network (CRANE), we present a new tomographic model of P-wave velocity perturbations for the lithosphere and upper mantle beneath the Cordillera-cration transition region in southwestern Canada. The inversion procedure properly accounts for the finite-volume sensitivities of measured travel time residuals, and the resulting model shows a greater resolution of upper mantle velocity heterogeneity beneath the study area than earlier approaches based on the classical ray-theoretical approach. Our model reveals a lateral change of P velocities from -0.5% to 0.5% down to ~200-km depth in a 50-km wide zone between the Alberta Basin and the foothills of the Rocky Mountains, which suggests a sharp structural gradient along the Cordillera deformation front. The stable cratonic lithosphere, delineated by positive P-velocity perturbations of 0.5% and greater, extends down to a maximum depth of ~180 km beneath the Archean Loverna Block (LB). In comparison, the mantle beneath the controversial Medicine Hat Block (MHB) exhibits significantly higher velocities in the uppermost mantle and a shallower (130-150 km depth) root, generally consistent with the average depth of the lithosphere-asthenosphere boundary beneath Southwest Western Canada Sedimentary Basin (WCSB). The complex shape of the lithospheric velocities under the MHB may be evidence of extensive erosion or a partial detachment of the Precambrian lithospheric root. Furthermore, distinct high velocity anomalies in LB and MHB, which are separated by 'normal' mantle block beneath the Vulcan structure (VS), suggest different Archean assembly and collision histories between these two tectonic blocks.

  18. Joint Chroma Subsampling and Distortion-Minimization-Based Luma Modification for RGB Color Images With Application.

    PubMed

    Chung, Kuo-Liang; Hsu, Tsu-Chun; Huang, Chi-Chao

    2017-10-01

    In this paper, we propose a novel and effective hybrid method, which joins the conventional chroma subsampling and the distortion-minimization-based luma modification together, to improve the quality of the reconstructed RGB full-color image. Assume the input RGB full-color image has been transformed to a YUV image, prior to compression. For each 2×2 UV block, one 4:2:0 subsampling is applied to determine the one subsampled U and V components, U s and V s . Based on U s , V s , and the corresponding 2×2 original RGB block, a main theorem is provided to determine the ideally modified 2×2 luma block in constant time such that the color peak signal-to-noise ratio (CPSNR) quality distortion between the original 2×2 RGB block and the reconstructed 2×2 RGB block can be minimized in a globally optimal sense. Furthermore, the proposed hybrid method and the delivered theorem are adjusted to tackle the digital time delay integration images and the Bayer mosaic images whose Bayer CFA structure has been widely used in modern commercial digital cameras. Based on the IMAX, Kodak, and screen content test image sets, the experimental results demonstrate that in high efficiency video coding, the proposed hybrid method has substantial quality improvement, in terms of the CPSNR quality, visual effect, CPSNR-bitrate trade-off, and Bjøntegaard delta PSNR performance, of the reconstructed RGB images when compared with existing chroma subsampling schemes.

  19. Designer amphiphilic proteins as building blocks for the intracellular formation of organelle-like compartments

    NASA Astrophysics Data System (ADS)

    Huber, Matthias C.; Schreiber, Andreas; von Olshausen, Philipp; Varga, Balázs R.; Kretz, Oliver; Joch, Barbara; Barnert, Sabine; Schubert, Rolf; Eimer, Stefan; Kele, Péter; Schiller, Stefan M.

    2015-01-01

    Nanoscale biological materials formed by the assembly of defined block-domain proteins control the formation of cellular compartments such as organelles. Here, we introduce an approach to intentionally ‘program’ the de novo synthesis and self-assembly of genetically encoded amphiphilic proteins to form cellular compartments, or organelles, in Escherichia coli. These proteins serve as building blocks for the formation of artificial compartments in vivo in a similar way to lipid-based organelles. We investigated the formation of these organelles using epifluorescence microscopy, total internal reflection fluorescence microscopy and transmission electron microscopy. The in vivo modification of these protein-based de novo organelles, by means of site-specific incorporation of unnatural amino acids, allows the introduction of artificial chemical functionalities. Co-localization of membrane proteins results in the formation of functionalized artificial organelles combining artificial and natural cellular function. Adding these protein structures to the cellular machinery may have consequences in nanobiotechnology, synthetic biology and materials science, including the constitution of artificial cells and bio-based metamaterials.

  20. Reliability study of Piezoelectric Structures Dedicated to Energy Harvesting by the Way of Blocking Force Investigation

    NASA Astrophysics Data System (ADS)

    Maaroufi, S.; Parrain, F.; Lefeuvre, E.; Boutaud, B.; Dal Molin, R.

    2015-12-01

    In this paper we propose an approach to study the reliability of piezoelectric structures and more precisely energy harvesting micro-devices dedicated to autonomous active medical implants (new generation pacemakers). The structure under test is designed as a bimorph piezoelectric cantilever with a seismic mass at its tip. Good understanding of material aging and mechanical failure is critical for this kind of system. To study the reliability and durability of the piezoelectric part we propose to establish a new accelerated methodology and an associated test bench where the environment and stimuli can be precisely controlled over a wide period of time. This will allow the identification of potential failure modes and the study of their impacts by the way of direct mechanical investigation based on stiffness and blocking force measurements performed periodically.

  1. An Approach for On-Board Software Building Blocks Cooperation and Interfaces Definition

    NASA Astrophysics Data System (ADS)

    Pascucci, Dario; Campolo, Giovanni; Candia, Sante; Lisio, Giovanni

    2010-08-01

    This paper provides an insight on the Avionic SW architecture developed by Thales Alenia Space Italy (TAS-I) to achieve structuring of the OBSW as a set of self-standing and re-usable building blocks. It is initially described the underlying framework for building blocks cooperation, which is based on ECSSE-70 packets forwarding (for services request to a building block) and standard parameters exchange for data communication. Subsequently it is discussed the high level of flexibility and scalability of the resulting architecture, reporting as example an implementation of the Failure Detection, Isolation and Recovery (FDIR) function which exploits the proposed architecture. The presented approach evolves from avionic SW architecture developed in the scope of the project PRIMA (Mult-Purpose Italian Re-configurable Platform) and has been adopted for the Sentinel-1 Avionic Software (ASW).

  2. Digital database of microfossil localities in Alameda and Contra Costa Counties, California

    USGS Publications Warehouse

    McDougall, Kristin; Block, Debra L.

    2014-01-01

    The eastern San Francisco Bay region (Contra Costa and Alameda Counties, California) is a geologically complex area divided by faults into a suite of tectonic blocks. Each block contains a unique stratigraphic sequence of Tertiary sediments that in most blocks unconformably overlie Mesozoic sediments. Age and environmental interpretations based on analysis of microfossil assemblages are key factors in interpreting geologic history, structure, and correlation of each block. Much of this data, however, is distributed in unpublished internal reports and memos, and is generally unavailable to the geologic community. In this report the U.S. Geological Survey microfossil data from the Tertiary sediments of Alameda and Contra Costa counties are analyzed and presented in a digital database, which provides a user-friendly summary of the micropaleontologic data, locality information, and biostratigraphic and ecologic interpretations.

  3. ALI (Autonomous Lunar Investigator): Revolutionary Approach to Exploring the Moon with Addressable Reconfigurable Technology

    NASA Technical Reports Server (NTRS)

    Clark, P. E.; Curtis, S. A.; Rilee, M. L.; Floyd, S. R.

    2005-01-01

    Addressable Reconfigurable Technology (ART) based structures: Mission Concepts based on Addressable Reconfigurable Technology (ART), originally studied for future ANTS (Autonomous Nanotechnology Swarm) Space Architectures, are now being developed as rovers for nearer term use in lunar and planetary surface exploration. The architecture is based on the reconfigurable tetrahedron as a building block. Tetrahedra are combined to form space-filling networks, shaped for the required function. Basic structural components are highly modular, addressable arrays of robust nodes (tetrahedral apices) from which highly reconfigurable struts (tetrahedral edges), acting as supports or tethers, are efficiently reversibly deployed/stowed, transforming and reshaping the structures as required.

  4. Microstructure synthesis control of biological polyhydroxyalkanoates with mass spectrometry

    NASA Astrophysics Data System (ADS)

    Pederson, Erik Norman

    Polyhydroxyalkanoates (PHA's) are a class of biologically produced polymers, or plastic, that is synthesized by various microorganisms. PHA's are made from biorenewable resources and are fully biodegradable and biocompatible, making them an environmentally friendly green polymer. A method of incorporating polymer microstructure into the PHA synthesized in Ralstonia eutropha was developed. These microstructures were synthesized with polyhydroxybutyrate (PHB) and poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) as the polymer domains. To synthesize the PHB V copolymer, the additional presence of valerate was required. To control valerate substrate additions to the bioreactor, an off-gas mass spectrometry (MS) feedback control system was developed. Important process information including the cell physiology, growth kinetics, and product formation kinetics in the bioreactor was obtained with MS and used to control microstructure synthesis. The two polymer microstructures synthesized were core-shell granules and block copolymers. Block copolymers control the structure of the individual polymer chains while core-shell granules control the organization of many polymer chains. Both these microstructures result in properties unattainable by blending the two polymers together. The core-shell structures were synthesized with controlled domain thickness based on a developed model. Different block copolymers compositions were synthesized by varying the switching time of the substrate pulses responsible for block copolymer synthesis. The block copolymers were tested to determine their chemical properties and cast into films to determine the materials properties. These block copolymer films possessed new properties not achieved by copolymers or blends of the two polymers.

  5. Laboratory testing of a building envelope segment based on cellular concrete

    NASA Astrophysics Data System (ADS)

    Fořt, Jan; Pavlík, Zbyšek; Černý, Robert

    2016-07-01

    Hygrothermal performance of a building envelope based on cellular concrete blocks is studied in the paper. Simultaneously, the strain fields induced by the heat and moisture changes are monitored. The studied wall is exposed to the climatic load corresponding to the winter climatic conditions of the moderate year for Prague. The winter climatic exposure is chosen in order to simulate the critical conditions of the building structure from the point of view of material performance and temperature and humidity loading. The evaluation of hygrothermal performance of a researched wall is done on the basis of relative humidity and temperature profiles measured along the cross section of the cellular concrete blocks. Strain gauges are fixed on the wall surface in expected orientation of the blocks expansion. The obtained results show a good hygrothermal function of the analyzed cellular concrete wall and its insignificant strain.

  6. Influence of aggregated morphology on carbon dioxide uptake of polythiophene conjugated organic networks

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

    Qiao, Shanlin; University of Chinese Academy of Sciences, Beijing 100049; Du, Zhengkun

    2014-04-01

    Two novel thiophene-based conjugated networks CMPs-TTT and CMPs-DTBT were designed and prepared with different steric configuration building blocks by FeCl{sub 3} oxidative coupling polymerization. UV–vis spectra, FE-SEM and TEM images showed CMPs-TTT and CMPs-DTBT having the different aggregated morphologies. After porous analysis and gas adsorption test, the result showed CO{sub 2} uptake capacity of CMPs-DTBT with amorphous aggregation model is 2.88 times and 2.66 times greater than that of CMPs-TTT with large lamellar structure model at 273 K and 298 K (1.0 bar), respectively. As a result, this communication proved that change the topological structure of the polymer can influencemore » the CO{sub 2} adsorption capacity significantly. - Graphical abstract: Two thiophene-based conjugated networks were prepared with different steric configuration building blocks, and they show various CO{sub 2} uptake capacity and sorption isosteric enthalpies, although they have identical chemical constitution. - Highlights: • Topological-directed design and synthesis two conjugated porous polymers. • Two thiophene-based CMPs show different aggregated morphologies. • They exhibit similar porosity structure and different CO{sub 2} uptake capacity.« less

  7. Enhanced Bioactivity of α-Tocopheryl Succinate Based Block Copolymer Nanoparticles by Reduced Hydrophobicity.

    PubMed

    Palao-Suay, Raquel; Aguilar, María Rosa; Parra-Ruiz, Francisco J; Maji, Samarendra; Hoogenboom, Richard; Rohner, Nathan A; Thomas, Susan N; Román, Julio San

    2016-12-01

    Well-structured amphiphilic copolymers are necessary to obtain self-assembled nanoparticles (NPs) based on synthetic polymers. Highly homogeneous and monodispersed macromolecules obtained by controlled polymerization have successfully been used for this purpose. However, disaggregation of the organized macromolecules is desired when a bioactive element, such as α-tocopheryl succinate, is introduced in self-assembled NPs and this element must be exposed or released to exert its action. The aim of this work is to demonstrate that the bioactivity of synthetic NPs based on defined reversible addition-fragmentation chain transfer polymerization copolymers can be enhanced by the introduction of hydrophilic comonomers in the hydrophobic segment. The amphiphilic terpolymers are based on poly(ethylene glycol) (PEG) as hydrophilic block, and a hydrophobic block based on a methacrylic derivative of α-tocopheryl succinate (MTOS) and small amounts of 2-hydroxyethyl methacrylate (HEMA) (PEG-b-poly(MTOS-co-HEMA)). The introduction of HEMA reduces hydrophobicity and introduces "disorder" both in the homogeneous blocks and the compact core of the corresponding NPs. These NPs are able to encapsulate additional α-tocopheryl succinate (α-TOS) with high efficiency and their biological activity is much higher than that described for the unmodified copolymers, proposedly due to more efficient degradation and release of α-TOS, demonstrating the importance of the hydrophilic-hydrophobic balance. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. SAQP and EUV block patterning of BEOL metal layers on IMEC's iN7 platform

    NASA Astrophysics Data System (ADS)

    Bekaert, Joost; Di Lorenzo, Paolo; Mao, Ming; Decoster, Stefan; Larivière, Stéphane; Franke, Joern-Holger; Blanco Carballo, Victor M.; Kutrzeba Kotowska, Bogumila; Lazzarino, Frederic; Gallagher, Emily; Hendrickx, Eric; Leray, Philippe; Kim, R. Ryoung-han; McIntyre, Greg; Colsters, Paul; Wittebrood, Friso; van Dijk, Joep; Maslow, Mark; Timoshkov, Vadim; Kiers, Ton

    2017-03-01

    The imec N7 (iN7) platform has been developed to evaluate EUV patterning of advanced logic BEOL layers. Its design is based on a 42 nm first-level metal (M1) pitch, and a 32 nm pitch for the subsequent M2 layer. With these pitches, the iN7 node is an `aggressive' full-scaled N7, corresponding to IDM N7, or foundry N5. Even in a 1D design style, single exposure of the 16 nm half-pitch M2 layer is very challenging for EUV lithography, because of its tight tip-to-tip configurations. Therefore, the industry is considering the hybrid use of ArFi-based SAQP combined with EUV Block as an alternative to EUV single exposure. As a consequence, the EUV Block layer may be one of the first layers to adopt EUV lithography in HVM. In this paper, we report on the imec iN7 SAQP + Block litho performance and process integration, targeting the M2 patterning for a 7.5 track logic design. The Block layer is exposed on an ASML NXE:3300 EUV-scanner at imec, using optimized illumination conditions and state-of-the-art metal-containing negative tone resist (Inpria). Subsequently, the SAQP and block structures are characterized in a morphological study, assessing pattern fidelity and CD/EPE variability. The work is an experimental feasibility study of EUV insertion, for SAQP + Block M2 patterning on an industry-relevant N5 use-case.

  9. Synthesis of sharply thermo and PH responsive PMA-b-PNIPAM-b-PEG-b-PNIPAM-b-PMA by RAFT radical polymerization and its schizophrenic micellization in aqueous solutions.

    PubMed

    Ahmadkhani, Lida; Abbasian, Mojtaba; Akbarzadeh, Abolfazl

    2017-01-01

    Sharply thermo- and pH-responsive pentablock terpolymer with a core-shell-corona structure was prepared by RAFT polymerization of N-isopropylacrylamide and methacrylic acid monomers using PEG-based benzoate-type of RAFT agent. The PEG-based RAFT agent could be easily synthesized by dihydroxyl-capped PEG with 4-cyano-4-(thiobenzoyl) sulfanylpentanoic acids, using esterification reaction. This pentablock terpolymer was characterized by 1 H NMR, FT-IR, and GPC. The PDI was obtained by GPC, indicating that the molecular weight distribution was narrow and the polymerization was well controlled. The thermo- and pH-responsive micellization of the pentablock terpolymer in aqueous solution was investigated using fluorescence spectroscopy technique, UV-vis transmittance, and TEM. The LCST of pentablock terpolymer increased (over 50 °C) compared to the NIPAM homopolymer (~32 °C), due to the incorporation of the hydrophilic PEG and PMA blocks in pentablock terpolymer (PNIPAM block as the core, PEG the block and the hydrophilic PMA block as the shell and the corona). Also, pH-dependent phase transition behavior shows at a pH value of about ~5.8, according to pKa of MAA. Thus, in acidic solution at room temperature, the pentablock terpolymer self-assembled to form core-shell-corona micelles, with the hydrophobic PMA block as the core, the PNIPAM block and the hydrophilic PEG block as the shell and the corona, respectively.

  10. Patchy micelles based on coassembly of block copolymer chains and block copolymer brushes on silica particles.

    PubMed

    Zhu, Shuzhe; Li, Zhan-Wei; Zhao, Hanying

    2015-04-14

    Patchy particles are a type of colloidal particles with one or more well-defined patches on the surfaces. The patchy particles with multiple compositions and functionalities have found wide applications from the fundamental studies to practical uses. In this research patchy micelles with thiol groups in the patches were prepared based on coassembly of free block copolymer chains and block copolymer brushes on silica particles. Thiol-terminated and cyanoisopropyl-capped polystyrene-block-poly(N-isopropylacrylamide) block copolymers (PS-b-PNIPAM-SH and PS-b-PNIPAM-CIP) were synthesized by reversible addition-fragmentation chain transfer polymerization and chemical modifications. Pyridyl disulfide-functionalized silica particles (SiO2-SS-Py) were prepared by four-step surface chemical reactions. PS-b-PNIPAM brushes on silica particles were prepared by thiol-disulfide exchange reaction between PS-b-PNIPAM-SH and SiO2-SS-Py. Surface micelles on silica particles were prepared by coassembly of PS-b-PNIPAM-CIP and block copolymer brushes. Upon cleavage of the surface micelles from silica particles, patchy micelles with thiol groups in the patches were obtained. Dynamic light scattering, transmission electron microscopy, and zeta-potential measurements demonstrate the preparation of patchy micelles. Gold nanoparticles can be anchored onto the patchy micelles through S-Au bonds, and asymmetric hybrid structures are formed. The thiol groups can be oxidized to disulfides, which results in directional assembly of the patchy micelles. The self-assembly behavior of the patchy micelles was studied experimentally and by computer simulation.

  11. Cell Penetrating Polymers Containing Guanidinium Trigger Apoptosis in Human Hepatocellular Carcinoma Cells unless Conjugated to a Targeting N-Acetyl-Galactosamine Block.

    PubMed

    Tan, Zhe; Dhande, Yogesh K; Reineke, Theresa M

    2017-12-20

    A series of 3-guanidinopropyl methacrylamide (GPMA)-based polymeric gene delivery vehicles were developed via aqueous reversible addition-fragmentation chain transfer (RAFT) polymerization. The polymers have been evaluated for their cellular internalization ability, transfection efficiency, and cytotoxicity. Two homopolymers: P(GPMA 20 ), P(GPMA 34 ), were synthesized to study the effect of guanidium polymer length on delivery efficiency and toxicity. In addition, an N-acetyl-d-galactosamine (GalNAc)-based hydrophilic block was incorporated to produce diblock polymers, which provides a neutral hydrophilic block that sterically protects plasmid-polymer complexes (polyplexes) from colloidal aggregation and aids polyplex targeting to hepatocytes via binding to asialoglycoprotein receptors (ASGPRs). Polyplexes formed with P(GPMA x ) (x = 20, 34) homopolymers were shown to be internalized via both energy-dependent and independent pathways, whereas polyplexes formed with block polymers were internalized through endocytosis. Notably, P(GPMA x ) polyplexes enter cells very efficiently but are also very toxic to human hepatocellular carcinoma (HepG2) cells and triggered cell apoptosis. In comparison, the presence of a carbohydrate block in the polymer structures reduced the cytotoxicity of the polyplex formulations and increased gene delivery efficiency with HepG2 cells. Transfection efficiency and toxicity studies were also carried out with HEK 293T (human embryonic kidney) cells for comparison. Results showed that polyplexes formed with the P(GPMA x ) homopolymers exhibit much higher transfection efficiency and lower toxicity with HEK 293T cells. The presence of the carbohydrate block did not further increase transfection efficiency in comparison to the homopolymers with HEK 293T cells, likely due to the lack of ASGPRs on the HEK 293T cell line. This study revealed that although guanidinium-based polymers have high membrane permeability, their application as plasmid delivery vehicles may be limited by their high cytotoxicity to certain cell types. Thus, the use of cell penetrating structures in polyplex formulations should be used with caution and carefully tailored toward individual cell/tissue types.

  12. Improved lossless intra coding for H.264/MPEG-4 AVC.

    PubMed

    Lee, Yung-Lyul; Han, Ki-Hun; Sullivan, Gary J

    2006-09-01

    A new lossless intra coding method based on sample-by-sample differential pulse code modulation (DPCM) is presented as an enhancement of the H.264/MPEG-4 AVC standard. The H.264/AVC design includes a multidirectional spatial prediction method to reduce spatial redundancy by using neighboring samples as a prediction for the samples in a block of data to be encoded. In the new lossless intra coding method, the spatial prediction is performed based on samplewise DPCM instead of in the block-based manner used in the current H.264/AVC standard, while the block structure is retained for the residual difference entropy coding process. We show that the new method, based on samplewise DPCM, does not have a major complexity penalty, despite its apparent pipeline dependencies. Experiments show that the new lossless intra coding method reduces the bit rate by approximately 12% in comparison with the lossless intra coding method previously included in the H.264/AVC standard. As a result, the new method is currently being adopted into the H.264/AVC standard in a new enhancement project.

  13. A Tabu-Search Heuristic for Deterministic Two-Mode Blockmodeling of Binary Network Matrices.

    PubMed

    Brusco, Michael; Steinley, Douglas

    2011-10-01

    Two-mode binary data matrices arise in a variety of social network contexts, such as the attendance or non-attendance of individuals at events, the participation or lack of participation of groups in projects, and the votes of judges on cases. A popular method for analyzing such data is two-mode blockmodeling based on structural equivalence, where the goal is to identify partitions for the row and column objects such that the clusters of the row and column objects form blocks that are either complete (all 1s) or null (all 0s) to the greatest extent possible. Multiple restarts of an object relocation heuristic that seeks to minimize the number of inconsistencies (i.e., 1s in null blocks and 0s in complete blocks) with ideal block structure is the predominant approach for tackling this problem. As an alternative, we propose a fast and effective implementation of tabu search. Computational comparisons across a set of 48 large network matrices revealed that the new tabu-search heuristic always provided objective function values that were better than those of the relocation heuristic when the two methods were constrained to the same amount of computation time.

  14. Electrically and chemically tunable soft-solid block copolymer structural color (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Park, Cheolmin

    2016-09-01

    1D photonic crystals based on the periodic stacking of two different dielectric layers have been widely studied due to their potential use in low-power reflective mode displays, e-books and sensors, but the fabrication of mechanically flexible polymer structural color (SC) films, with electro-active color switching, remains challenging. Here, we demonstrate free-standing electric field tunable ionic liquid swollen block copolymer films. Placement of a polymer/ionic liquid (IL) film-reservoir adjacent to a self-assembled poly(styrene-block-quaternized 2vinyl pyridine) (PS-b-QP2VP) copolymer SC film allowed the development of R, G and B full-color SC block copolymer films by swelling of the QP2VP domains by the ionic liquid associated with water molecules. The IL-polymer/BCP SC film is mechanically flexible with excellent color stability over several days at ambient conditions. The selective swelling of the QP2VP domains could be controlled by both the ratio of the IL to a polymer in the gel-like IL reservoir layer and by an applied voltage in the range of -3V to +6V using a metal/IL reservoir/SC film/IL reservoir/metal capacitor type device.

  15. Electrochemical aptasensor based on the dual-amplification of G-quadruplex horseradish peroxidase-mimicking DNAzyme and blocking reagent-horseradish peroxidase.

    PubMed

    Yuan, Yali; Gou, Xuxu; Yuan, Ruo; Chai, Yaqin; Zhuo, Ying; Mao, Li; Gan, Xianxue

    2011-06-15

    A simple electrochemical aptasensor for sensitive detection of thrombin was fabricated with G-quadruplex horseradish peroxidase-mimicking DNAzyme (hemin/G-quadruplex system) and blocking reagent-horseradish peroxidase as dual signal-amplification scheme. Gold nanoparticles (nano-Au) were firstly electrodeposited onto single wall nanotube (SWNT)-graphene modified electrode surface for the immobilization of electrochemical probe of nickel hexacyanoferrates nanoparticles (NiHCFNPs). Subsequently, another nano-Au layer was electrodeposited for further immobilization of thrombin aptamer (TBA), which later formed hemin/G-quadruplex system with hemin. Horseradish peroxidases (HRP) then served as blocking reagent to block possible remaining active sites and avoided the non-specific adsorption. In the presence of thrombin, the TBA binded to thrombin and the hemin released from the hemin/G-quadruplex electrocatalytic structure, increasing steric hindrance of the aptasensor and decomposing hemin/G-quadruplex electrocatalytic structure, which finally decreased the electrocatalytic efficiency of aptasensor toward H(2)O(2) in the presence of NiHCFNPs with a decreased electrochemical signal. On the basis of the synergistic amplifying action, a detection limit as low as 2 pM for thrombin was obtained. Copyright © 2011 Elsevier B.V. All rights reserved.

  16. Cloud computing-based TagSNP selection algorithm for human genome data.

    PubMed

    Hung, Che-Lun; Chen, Wen-Pei; Hua, Guan-Jie; Zheng, Huiru; Tsai, Suh-Jen Jane; Lin, Yaw-Ling

    2015-01-05

    Single nucleotide polymorphisms (SNPs) play a fundamental role in human genetic variation and are used in medical diagnostics, phylogeny construction, and drug design. They provide the highest-resolution genetic fingerprint for identifying disease associations and human features. Haplotypes are regions of linked genetic variants that are closely spaced on the genome and tend to be inherited together. Genetics research has revealed SNPs within certain haplotype blocks that introduce few distinct common haplotypes into most of the population. Haplotype block structures are used in association-based methods to map disease genes. In this paper, we propose an efficient algorithm for identifying haplotype blocks in the genome. In chromosomal haplotype data retrieved from the HapMap project website, the proposed algorithm identified longer haplotype blocks than an existing algorithm. To enhance its performance, we extended the proposed algorithm into a parallel algorithm that copies data in parallel via the Hadoop MapReduce framework. The proposed MapReduce-paralleled combinatorial algorithm performed well on real-world data obtained from the HapMap dataset; the improvement in computational efficiency was proportional to the number of processors used.

  17. Cloud Computing-Based TagSNP Selection Algorithm for Human Genome Data

    PubMed Central

    Hung, Che-Lun; Chen, Wen-Pei; Hua, Guan-Jie; Zheng, Huiru; Tsai, Suh-Jen Jane; Lin, Yaw-Ling

    2015-01-01

    Single nucleotide polymorphisms (SNPs) play a fundamental role in human genetic variation and are used in medical diagnostics, phylogeny construction, and drug design. They provide the highest-resolution genetic fingerprint for identifying disease associations and human features. Haplotypes are regions of linked genetic variants that are closely spaced on the genome and tend to be inherited together. Genetics research has revealed SNPs within certain haplotype blocks that introduce few distinct common haplotypes into most of the population. Haplotype block structures are used in association-based methods to map disease genes. In this paper, we propose an efficient algorithm for identifying haplotype blocks in the genome. In chromosomal haplotype data retrieved from the HapMap project website, the proposed algorithm identified longer haplotype blocks than an existing algorithm. To enhance its performance, we extended the proposed algorithm into a parallel algorithm that copies data in parallel via the Hadoop MapReduce framework. The proposed MapReduce-paralleled combinatorial algorithm performed well on real-world data obtained from the HapMap dataset; the improvement in computational efficiency was proportional to the number of processors used. PMID:25569088

  18. Preparation, characterization, and in vitro activity evaluation of triblock copolymer-based polymersomes for drugs delivery

    NASA Astrophysics Data System (ADS)

    Besada, Lucas N.; Peruzzo, Pablo; Cortizo, Ana M.; Cortizo, M. Susana

    2018-03-01

    Polymersomes are polymer-based vesicles that form upon hydration of amphiphilic block copolymers and display high stability and durability, due to their mechanical and physical properties. They have hydrophilic reservoirs as well as thick hydrophobic membranes; allowing to encapsulate both water-soluble bioactive agent and hydrophobic drugs. In this study, poly ethylene glycol (PEG3350 and PEG6000) were used as hydrophilic part and poly(vinyl benzoate) (PVBz) as hydrophobic block to synthesize amphiphilic triblock copolymers (PVBz- b-PEG- b-PVBz). Different proportions of hydrophilic/hydrophobic part were assayed in order to obtain polymersomes by solvent injection method. For the synthesis of the copolymers, the initial block of PEG was derived to obtain a macroinitiator through a xanthate functional group (PEGX3 or PEGX6) and the polymerization of vinyl benzoate was carried out through reversible addition-fragmentation chain transfer polymerization (RAFT). The structure of PEGX and copolymers was confirmed by Infrared, 1H-NMR and UV-Vis spectrometry, while the average molecular weight (Mw) and polydispersity index (PI) were determined by size exclusion chromatography (SEC). The structures adopted by the copolymers in aqueous solution by self-assembly were investigated using transmission electron microscopy (TEM), dynamic light scattering (DLS) and small-angle X-ray scattering (SAXS). Both techniques confirm that polymersomes were obtained for a fraction of hydrophilic block ( f) ≈ 35 ± 10%, with a diameter of 38.3 ± 0.3 nm or 22.5 ± 0.7 nm, as determined by TEM and according to the M w of the precursor block copolymer. In addition, we analyzed the possible cytotoxicity in view of its potential application as biomedical nanocarrier. The results suggest that polymersomes seem not induce cytotoxicity during the periods of time tested.

  19. Structured Set Intra Prediction With Discriminative Learning in a Max-Margin Markov Network for High Efficiency Video Coding

    PubMed Central

    Dai, Wenrui; Xiong, Hongkai; Jiang, Xiaoqian; Chen, Chang Wen

    2014-01-01

    This paper proposes a novel model on intra coding for High Efficiency Video Coding (HEVC), which simultaneously predicts blocks of pixels with optimal rate distortion. It utilizes the spatial statistical correlation for the optimal prediction based on 2-D contexts, in addition to formulating the data-driven structural interdependences to make the prediction error coherent with the probability distribution, which is desirable for successful transform and coding. The structured set prediction model incorporates a max-margin Markov network (M3N) to regulate and optimize multiple block predictions. The model parameters are learned by discriminating the actual pixel value from other possible estimates to maximize the margin (i.e., decision boundary bandwidth). Compared to existing methods that focus on minimizing prediction error, the M3N-based model adaptively maintains the coherence for a set of predictions. Specifically, the proposed model concurrently optimizes a set of predictions by associating the loss for individual blocks to the joint distribution of succeeding discrete cosine transform coefficients. When the sample size grows, the prediction error is asymptotically upper bounded by the training error under the decomposable loss function. As an internal step, we optimize the underlying Markov network structure to find states that achieve the maximal energy using expectation propagation. For validation, we integrate the proposed model into HEVC for optimal mode selection on rate-distortion optimization. The proposed prediction model obtains up to 2.85% bit rate reduction and achieves better visual quality in comparison to the HEVC intra coding. PMID:25505829

  20. A Novel DEM Approach to Simulate Block Propagation on Forested Slopes

    NASA Astrophysics Data System (ADS)

    Toe, David; Bourrier, Franck; Dorren, Luuk; Berger, Frédéric

    2018-03-01

    In order to model rockfall on forested slopes, we developed a trajectory rockfall model based on the discrete element method (DEM). This model is able to take the complex mechanical processes at work during an impact into account (large deformations, complex contact conditions) and can explicitly simulate block/soil, block/tree contacts as well as contacts between neighbouring trees. In this paper, we describe the DEM model developed and we use it to assess the protective effect of different types of forest. In addition, we compared it with a more classical rockfall simulation model. The results highlight that forests can significantly reduce rockfall hazard and that the spatial structure of coppice forests has to be taken into account in rockfall simulations in order to avoid overestimating the protective role of these forest structures against rockfall hazard. In addition, the protective role of the forests is mainly influenced by the basal area. Finally, the advantages and limitations of the DEM model were compared with classical rockfall modelling approaches.

  1. The Origin of Hierarchical Structure Formation in Highly Grafted Symmetric Supramolecular Double-Comb Diblock Copolymers.

    PubMed

    Hofman, Anton H; Reza, Mehedi; Ruokolainen, Janne; Ten Brinke, Gerrit; Loos, Katja

    2017-09-01

    Involving supramolecular chemistry in self-assembling block copolymer systems enables design of complex macromolecular architectures that, in turn, could lead to complex phase behavior. It is an elegant route, as complicated and sensitive synthesis techniques can be avoided. Highly grafted double-comb diblock copolymers based on symmetric double hydrogen bond accepting poly(4-vinylpyridine)-block-poly(N-acryloylpiperidine) diblock copolymers and donating 3-nonadecylphenol amphiphiles are realized and studied systematically by changing the molecular weight of the copolymer. Double perpendicular lamellae-in-lamellae are formed in all complexes, independent of the copolymer molecular weight. Temperature-resolved measurements demonstrate that the supramolecular nature and ability to crystallize are responsible for the formation of such multiblock-like structures. Because of these driving forces and severe plasticization of the complexes in the liquid crystalline state, this supramolecular approach can be useful for steering self-assembly of both low- and high-molecular-weight block copolymer systems. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Automatic extraction of tree crowns from aerial imagery in urban environment

    NASA Astrophysics Data System (ADS)

    Liu, Jiahang; Li, Deren; Qin, Xunwen; Yang, Jianfeng

    2006-10-01

    Traditionally, field-based investigation is the main method to investigate greenbelt in urban environment, which is costly and low updating frequency. In higher resolution image, the imagery structure and texture of tree canopy has great similarity in statistics despite the great difference in configurations of tree canopy, and their surface structures and textures of tree crown are very different from the other types. In this paper, we present an automatic method to detect tree crowns using high resolution image in urban environment without any apriori knowledge. Our method catches unique structure and texture of tree crown surface, use variance and mathematical expectation of defined image window to position the candidate canopy blocks coarsely, then analysis their inner structure and texture to refine these candidate blocks. The possible spans of all the feature parameters used in our method automatically generate from the small number of samples, and HOLE and its distribution as an important characteristics are introduced into refining processing. Also the isotropy of candidate image block and holes' distribution is integrated in our method. After introduction the theory of our method, aerial imageries were used ( with a resolution about 0.3m ) to test our method, and the results indicate that our method is an effective approach to automatically detect tree crown in urban environment.

  3. RNA and RNP as Building Blocks for Nanotechnology and Synthetic Biology.

    PubMed

    Ohno, Hirohisa; Saito, Hirohide

    2016-01-01

    Recent technologies that aimed to elucidate cellular function have revealed essential roles for RNA molecules in living systems. Our knowledge concerning functional and structural information of naturally occurring RNA and RNA-protein (RNP) complexes is increasing rapidly. RNA and RNP interaction motifs are structural units that function as building blocks to constitute variety of complex structures. RNA-central synthetic biology and nanotechnology are constructive approaches that employ the accumulated information and build synthetic RNA (RNP)-based circuits and nanostructures. Here, we describe how to design and construct synthetic RNA (RNP)-based devices and structures at the nanometer-scale for biological and future therapeutic applications. RNA/RNP nanostructures can also be utilized as the molecular scaffold to control the localization or interactions of target molecule(s). Moreover, RNA motifs recognized by RNA-binding proteins can be applied to make protein-responsive translational "switches" that can turn gene expression "on" or "off" depending on the intracellular environment. This "synthetic RNA and RNP world" will expand tools for nanotechnology and synthetic biology. In addition, these reconstructive approaches would lead to a greater understanding of building principle in naturally occurring RNA/RNP molecules and systems. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Genetic instability associated with loop or stem–loop structures within transcription units can be independent of nucleotide excision repair

    PubMed Central

    Burns, John A; Chowdhury, Moinuddin A; Cartularo, Laura; Berens, Christian; Scicchitano, David A

    2018-01-01

    Abstract Simple sequence repeats (SSRs) are found throughout the genome, and under some conditions can change in length over time. Germline and somatic expansions of trinucleotide repeats are associated with a series of severely disabling illnesses, including Huntington's disease. The underlying mechanisms that effect SSR expansions and contractions have been experimentally elusive, but models suggesting a role for DNA repair have been proposed, in particular the involvement of transcription-coupled nucleotide excision repair (TCNER) that removes transcription-blocking DNA damage from the transcribed strand of actively expressed genes. If the formation of secondary DNA structures that are associated with SSRs were to block RNA polymerase progression, TCNER could be activated, resulting in the removal of the aberrant structure and a concomitant change in the region's length. To test this, TCNER activity in primary human fibroblasts was assessed on defined DNA substrates containing extrahelical DNA loops that lack discernible internal base pairs or DNA stem–loops that contain base pairs within the stem. The results show that both structures impede transcription elongation, but there is no corresponding evidence that nucleotide excision repair (NER) or TCNER operates to remove them. PMID:29474673

  5. Large Deformation Analysis of a High Steep Slope Relating to the Laxiwa Reservoir, China

    NASA Astrophysics Data System (ADS)

    Lin, Peng; Liu, Xiaoli; Hu, Senying; Li, Pujian

    2016-06-01

    The unstable rock slope in the Laxiwa reservoir area of the Yellow River upstream, China, shows the signs of gravitational and water-impounding induced large deformations over an area of 1.15 × 105 m2. Slope movements have been measured daily at more than 560 observation points since 2009, when the reservoir was first impounded. At two of these points, an average daily movement of around 60-80 mm has ever been observed since the beginning of the impounding. Based on the observed deformations and the geology of the site, a fluid-solid coupling model was then adopted to investigate the existing rockslide activity to better understand the mechanism underlying the large deformations. The results from the field observation, kinematic analysis and numerical modeling indicate that the slope instability is dominated by the strong structurally controlled unstable rock mass. Based on an integrated overview of these analyses, a new toppling mode, i.e. the so-called `conjugate block' mode, is proposed to explain the large deformation mechanism of the slope. The conjugate block is formed by a `dumping block' and toppling blocks. The large deformation of the slope is dominated by (1) a toppling component and (2) a subsiding bilinear wedge induced by planar sliding along the deep-seated faults. Following a thorough numerical analysis, it is concluded that small collapses of rock blocks along the slope will be more frequent with the impounding process continuing and the water level fluctuating during the subsequent operation period. Based on a shear strength reduction method and field monitoring, four controlling faults are identified and the instability of the loose structure in the surface layer is analyzed and discussed. The factor of safety against the sliding failure along the deep seated fractures in the slope is 1.72, which reveals that (1) the collapse of the free-standing fractured blocks cannot be ruled out and the volume of the unstable blocks may be greater than 100,000 m3; (2) the collapse of the whole slope, i.e. with the volume being greater than 92 million m3, or a very large collapse involving several million m3, is considered to be of very low likelihood, unless there are extreme conditions, such as earthquakes and exceptionally heavy rain.

  6. Dispersion and alignment of nanorods in cylindrical block copolymer thin films.

    PubMed

    Rasin, Boris; Chao, Huikuan; Jiang, Guoqian; Wang, Dongliang; Riggleman, Robert A; Composto, Russell J

    2016-02-21

    Although significant progress has been made in controlling the dispersion of spherical nanoparticles in block copolymer thin films, our ability to disperse and control the assembly of anisotropic nanoparticles into well-defined structures is lacking in comparison. Here we use a combination of experiments and field theoretic simulations to examine the assembly of gold nanorods (AuNRs) in a block copolymer. Experimentally, poly(2-vinylpyridine)-grafted AuNRs (P2VP-AuNRs) are incorporated into poly(styrene)-b-poly(2-vinylpyridine) (PS-b-P2VP) thin films with a vertical cylinder morphology. At sufficiently low concentrations, the AuNRs disperse in the block copolymer thin film. For these dispersed AuNR systems, atomic force microscopy combined with sequential ultraviolet ozone etching indicates that the P2VP-AuNRs segregate to the base of the P2VP cylinders. Furthermore, top-down transmission electron microscopy imaging shows that the P2VP-AuNRs mainly lie parallel to the substrate. Our field theoretic simulations indicate that the NRs are strongly attracted to the cylinder base where they can relieve the local stretching of the minority block of the copolymer. These simulations also indicate conditions that will drive AuNRs to adopt a vertical orientation, namely by increasing nanorod length and/or reducing the wetting of the short block towards the substrate.

  7. Substrate structures for InP-based devices

    DOEpatents

    Wanlass, Mark W.; Sheldon, Peter

    1990-01-01

    A substrate structure for an InP-based semiconductor device having an InP based film is disclosed. The substrate structure includes a substrate region having a lightweight bulk substrate and an upper GaAs layer. An interconnecting region is disposed between the substrate region and the InP-based device. The interconnecting region includes a compositionally graded intermediate layer substantially lattice-matched at one end to the GaAs layer and substantially lattice-matched at the opposite end to the InP-based film. The interconnecting region further includes a dislocation mechanism disposed between the GaAs layer and the InP-based film in cooperation with the graded intermediate layer, the buffer mechanism blocking and inhibiting propagation of threading dislocations between the substrate region, and the InP-based device.

  8. Cooperation of Amphiphilicity and Crystallization for Regulating the Self-Assembly of Poly(ethylene glycol)-block-poly(lactic acid) Copolymers.

    PubMed

    Wang, Zhen; Cao, Yuanyuan; Song, Jiaqi; Xie, Zhigang; Wang, Yapei

    2016-09-20

    Tuning the amphiphilicity of block copolymers has been extensively exploited to manipulate the morphological transition of aggregates. The introduction of crystallizable moieties into the amphiphilic copolymers also offers increasing possibilities for regulating self-assembled structures. In this work, we demonstrate a detailed investigation of the self-assembly behavior of amphiphilic poly(ethylene glycol)-block-poly(l-lactic acid) (PEG-b-PLLA) diblock copolymers with the assistance of a common solvent in aqueous solution. With a given length of the PEG block, the molecular weight of the PLA block has great effect on the morphologies of self-assembled nanoaggregates as a result of varying molecular amphiphilicity and polymer crystallization. Common solvents including N,N-dimethylformamide, dioxane, and tetrahydrofuran involved in the early stage of self-assembly led to the change in chain configuration, which further influences the self-assembly of block copolymers. This study expanded the scope of PLA-based copolymers and proposed a possible mechanism of the sphere-to-lozenge and platelet-to-cylinder morphological transitions.

  9. Design of short peptides to block BTLA/HVEM interactions for promoting anticancer T-cell responses

    PubMed Central

    Spodzieja, Marta; Lach, Sławomir; Iwaszkiewicz, Justyna; Cesson, Valérie; Kalejta, Katarzyna; Olive, Daniel; Michielin, Olivier; Speiser, Daniel E.; Zoete, Vincent

    2017-01-01

    Antibody based immune-checkpoint blockade therapy is a major breakthrough in oncology, leading to clinical benefit for cancer patients. Among the growing family of inhibitory receptors, the B and T lymphocyte attenuator (BTLA), which interacts with herpes virus entry mediator (HVEM), is a promising target for immunotherapy. Indeed, BTLA inhibits T-cell proliferation and cytokine production. The crystal structure of the BTLA/HVEM complex has shown that the HVEM(26–38) fragment is directly involved in protein binding. We designed and analyzed the capacity of several analogs of this fragment to block the ligation between BTLA and HVEM, using competitive ELISA and cellular assay. We found that the HVEM(23–39) peptide can block BTLA/HVEM ligation. However, the blocking ability was due to the Cys encompassed in this peptide and that even free cysteine targeted the BTLA protein and blocked its interaction with HVEM. These data highlight a Cys-related artefact in vitro, which should be taken in consideration for future development of BTLA/HVEM blocking compounds. PMID:28594868

  10. Automatic graph-cut based segmentation of bones from knee magnetic resonance images for osteoarthritis research.

    PubMed

    Ababneh, Sufyan Y; Prescott, Jeff W; Gurcan, Metin N

    2011-08-01

    In this paper, a new, fully automated, content-based system is proposed for knee bone segmentation from magnetic resonance images (MRI). The purpose of the bone segmentation is to support the discovery and characterization of imaging biomarkers for the incidence and progression of osteoarthritis, a debilitating joint disease, which affects a large portion of the aging population. The segmentation algorithm includes a novel content-based, two-pass disjoint block discovery mechanism, which is designed to support automation, segmentation initialization, and post-processing. The block discovery is achieved by classifying the image content to bone and background blocks according to their similarity to the categories in the training data collected from typical bone structures. The classified blocks are then used to design an efficient graph-cut based segmentation algorithm. This algorithm requires constructing a graph using image pixel data followed by applying a maximum-flow algorithm which generates a minimum graph-cut that corresponds to an initial image segmentation. Content-based refinements and morphological operations are then applied to obtain the final segmentation. The proposed segmentation technique does not require any user interaction and can distinguish between bone and highly similar adjacent structures, such as fat tissues with high accuracy. The performance of the proposed system is evaluated by testing it on 376 MR images from the Osteoarthritis Initiative (OAI) database. This database included a selection of single images containing the femur and tibia from 200 subjects with varying levels of osteoarthritis severity. Additionally, a full three-dimensional segmentation of the bones from ten subjects with 14 slices each, and synthetic images with background having intensity and spatial characteristics similar to those of bone are used to assess the robustness and consistency of the developed algorithm. The results show an automatic bone detection rate of 0.99 and an average segmentation accuracy of 0.95 using the Dice similarity index. Copyright © 2011 Elsevier B.V. All rights reserved.

  11. Molecular diodes based on conjugated diblock co-oligomers.

    PubMed

    Ng, Man-Kit; Lee, Dong-Chan; Yu, Luping

    2002-10-09

    This report describes synthesis and characterization of a molecular diode based upon a diblock conjugated oligomer system. This system consists of two conjugated blocks with opposite electronic demand. The molecular structure exhibits a built-in electronic asymmetry, much like a semiconductor p-n junction. Electrical measurements by scanning tunneling spectroscopy (STS) clearly revealed a pronounced rectifying effect. Definitive proof for the molecular nature of the rectifying effect in this conjugated diblock molecule is provided by control experiments with a structurally similar reference compound.

  12. Hyperbranched PEGmethacrylate linear pDMAEMA block copolymer as an efficient non-viral gene delivery vector.

    PubMed

    Mathew, Asha; Cao, Hongliang; Collin, Estelle; Wang, Wenxin; Pandit, Abhay

    2012-09-15

    A unique hyperbranched polymeric system with a linear poly-2-dimethylaminoethyl methacrylate (pDMAEMA) block and a hyperbranched polyethylene glycol methyl ether methacrylate (PEGMEMA) and ethylene dimethacrylate (EGDMA) block was designed and synthesized via deactivation enhanced atom transfer radical polymerisation (DE-ATRP) for efficient gene delivery. Using this unique structure, with a linear pDMAEMA block, which efficiently binds to plasmid DNA (pDNA) and hyperbranched polyethylene glycol (PEG) based block as a protective shell, we were able to maintain high transfection levels without sacrificing cellular viability even at high doses. The transfection capability and cytotoxicity of the polymers over a range of pDNA concentration were analysed and the results were compared to commercially available transfection vectors such as polyethylene imine (branched PEI, 25 kDa), partially degraded poly(amido amine)dendrimer (dPAMAM; commercial name: SuperFect(®)) in fibroblasts and adipose tissue derived stem cells (ADSCs). Copyright © 2012 Elsevier B.V. All rights reserved.

  13. Fast assembly of ordered block copolymer nanostructures through microwave annealing.

    PubMed

    Zhang, Xiaojiang; Harris, Kenneth D; Wu, Nathanael L Y; Murphy, Jeffrey N; Buriak, Jillian M

    2010-11-23

    Block copolymer self-assembly is an innovative technology capable of patterning technologically relevant substrates with nanoscale precision for a range of applications from integrated circuit fabrication to tissue interfacing, for example. In this article, we demonstrate a microwave-based method of rapidly inducing order in block copolymer structures. The technique involves the usage of a commercial microwave reactor to anneal block copolymer films in the presence of appropriate solvents, and we explore the effect of various parameters over the polymer assembly speed and defect density. The approach is applied to the commonly used poly(styrene)-b-poly(methyl methacrylate) (PS-b-PMMA) and poly(styrene)-b-poly(2-vinylpyridine) (PS-b-P2VP) families of block copolymers, and it is found that the substrate resistivity, solvent environment, and anneal temperature all critically influence the self-assembly process. For selected systems, highly ordered patterns were achieved in less than 3 min. In addition, we establish the compatibility of the technique with directed assembly by graphoepitaxy.

  14. Kinematics and mechanics of tectonic block rotations

    NASA Technical Reports Server (NTRS)

    Nur, Amos; Scotti, Oona; Ron, Hagai

    1989-01-01

    Paleomagnetic, structural geology, and rock mechanics data are combined to explore the validity of the block rotation concept and its significance. The analysis is based on data from (1) Northern Israel, where fault slip and spacing are used to predict block rotation; (2) the Mojave Desert, with well-documented strike-slip fault sets, organized in at least three major domains; (3) the Lake Mead, Nevada, fault system with well-defined sets of strike-slip faults, which, in contrast to the Mojave region, are surrounded with domains of normal faults; and (4) the San Gabriel Mountains domain with a multiple set of strike-slip faults. It is found that block rotations can have a profound influence on the interpretation of geodetic measurements and the inversion of geodetic data, especially the type collected in GPS surveys. Furthermore, block rotations and domain boundaries may be involved in creating the heterogeneities along active fault systems which are responsible for the initiation and termination of earthquake rupture.

  15. How Young Children Learn to Program with Sensor, Action, and Logic Blocks

    ERIC Educational Resources Information Center

    Wyeth, Peta

    2008-01-01

    Electronic Blocks are a new programming environment designed specifically for children aged between 3 and 8 years. These physical, stackable blocks include sensor blocks, action blocks, and logic blocks. By connecting these blocks, children can program a wide variety of structures that interact with one another and the environment. Electronic…

  16. Improving the performance of AlGaN-based deep-ultraviolet light-emitting diodes using electron blocking layer with a heart-shaped graded Al composition

    NASA Astrophysics Data System (ADS)

    Kwon, M. R.; Park, T. H.; Lee, T. H.; Lee, B. R.; Kim, T. G.

    2018-04-01

    We propose a design for highly efficient AlGaN-based deep-ultraviolet light-emitting diodes (DUV LEDs) using a heart-shaped graded Al composition electron-blocking layer (EBL). This novel structure reduced downward band bending at the interface between the last quantum barrier and the EBL and flattened the electrostatic field in the interlayer between the barriers of the multi-quantum barrier EBL. Consequently, electron leakage was significantly suppressed and hole injection efficiency was found to have improved. The parameter values of simulation were extracted from the experimental data of the reference DUV LEDs. Using the SimuLED, we compared the electrical and optical properties of three structures with different Al compositions in the active region and the EBL. The internal quantum efficiency of the proposed structure was shown to exceed those of the reference DUV LEDs by a factor of 1.9. Additionally, the output power at 20 mA was found to increase by a factor of 2.1.

  17. Reconstructing Past Admixture Processes from Local Genomic Ancestry Using Wavelet Transformation

    PubMed Central

    Sanderson, Jean; Sudoyo, Herawati; Karafet, Tatiana M.; Hammer, Michael F.; Cox, Murray P.

    2015-01-01

    Admixture between long-separated populations is a defining feature of the genomes of many species. The mosaic block structure of admixed genomes can provide information about past contact events, including the time and extent of admixture. Here, we describe an improved wavelet-based technique that better characterizes ancestry block structure from observed genomic patterns. principal components analysis is first applied to genomic data to identify the primary population structure, followed by wavelet decomposition to develop a new characterization of local ancestry information along the chromosomes. For testing purposes, this method is applied to human genome-wide genotype data from Indonesia, as well as virtual genetic data generated using genome-scale sequential coalescent simulations under a wide range of admixture scenarios. Time of admixture is inferred using an approximate Bayesian computation framework, providing robust estimates of both admixture times and their associated levels of uncertainty. Crucially, we demonstrate that this revised wavelet approach, which we have released as the R package adwave, provides improved statistical power over existing wavelet-based techniques and can be used to address a broad range of admixture questions. PMID:25852078

  18. Structural and biological mimicry of protein surface recognition by [alpha/beta]-peptide foldamers

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

    Horne, W. Seth; Johnson, Lisa M.; Ketas, Thomas J.

    Unnatural oligomers that can mimic protein surfaces offer a potentially useful strategy for blocking biomedically important protein-protein interactions. Here we evaluate an approach based on combining {alpha}- and {beta}-amino acid residues in the context of a polypeptide sequence from the HIV protein gp41, which represents an excellent testbed because of the wealth of available structural and biological information. We show that {alpha}/{beta}-peptides can mimic structural and functional properties of a critical gp41 subunit. Physical studies in solution, crystallographic data, and results from cell-fusion and virus-infectivity assays collectively indicate that the gp41-mimetic {alpha}/{beta}-peptides effectively block HIV-cell fusion via a mechanism comparablemore » to that of gp41-derived {alpha}-peptides. An optimized {alpha}/{beta}-peptide is far less susceptible to proteolytic degradation than is an analogous {alpha}-peptide. Our findings show how a two-stage design approach, in which sequence-based {alpha} {yields} {beta} replacements are followed by site-specific backbone rigidification, can lead to physical and biological mimicry of a natural biorecognition process.« less

  19. World Virtual Observatory Organization

    NASA Astrophysics Data System (ADS)

    Ignatyev, Mikhail; Pinigin, Gennadij

    On the base of experience of our Unoversity and Observatory we investigate the seven blocks model of virtual organization for consolidation of resources. This model consists of the next blocks: 1.Population-scientists students robots and agents. 2.Aspiration of population groups. 3.Territory. 4.Production. 5.Ecology and safety. 6.Finance. 7. External relations - input and output flows of population information resources.The world virtual observatory is the virtual world which consists of three groups of variables - appearances essences and structured uncertainty which defines the number and distribution of arbitrary coefficients in equivalent equations. The consolodation of recources permit to create the large telescopes with distributed structure on our planet and cosmos. Virtual instruments can have the best characteristics by means of collective effects which have investigated in our paper.

  20. The structure-directed effect of Al-based metal–organic frameworks on fabrication of alumina by thermal treatment

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

    Liu, Dandan, E-mail: liudandan_upc@126.com; Dai, Fangna, E-mail: fndai@upc.edu.cn; Collage of Science, China University of Petroleum

    2015-05-15

    Highlights: • We use Al-MOFs as precursor in the fabrication process of mesoporous alumina by thermal treatment. • The obtained mesoporous alumina has dual pore system and five-fold aluminum. • The aluminum building units in the precursor show structure-directed effect on the formation of alumina. - Abstract: In this work, the block-shaped Al-based metal–organic frameworks (Al-MOFs) MIL-53 have been synthesized by hydrothermal method. To detect the correlation between the structure of Al-MOFs and the formation of alumina, the ligands are eliminated by thermal treatment. MIL-53 and the calcination products were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR),more » scanning electron microscope (SEM), transmission electron microscopy (TEM), nitrogen adsorption–desorption and solid-state {sup 27}Al nuclear magnetic resonance ({sup 27}Al NMR). It was found that after calcination, the block-shaped Al-MOFs precursor turns into high-crystallinity mesoporous alumina nanosheets, and the thermal treatment product γ-alumina possesses a dual pore system and a large surface area (146 m{sup 2}/g), with five-fold aluminum. During the thermal treatment process, the structure of MIL-53 and its secondary building units have structure-directed effect in the formation of alumina.« less

  1. Noncovalent fabrication and tunable fusion of block copolymer-giant polyoxometalate hybrid micelles.

    PubMed

    Zhang, Liying; Li, Haolong; Wu, Lixin

    2014-09-21

    The block copolymers (BCs), as structure-directing agents, co-assembling with nanoscale inorganic additives is an important route to fabricate nanostructured hybrid materials. In this work, we present a facile approach to fabricate hybrid micelles composed of BCs and polyoxometalates (POMs), in which the POM clusters are premodified with the groups that can specifically interact with a certain BC block. A representative POM (NH4)42[Mo(132)O(372)(CH(3)COO)(30)(H2O)72] (Mo(132)) is chosen as the example and encapsulated with cationic molecules containing carboxyphenyl groups through electrostatic interactions, and then the resulting hybrid complex can further co-assemble with poly(styrene-block-4-vinylpyridine) (PS-b-P4VP) through hydrogen bonding with the pyridine groups, which leads to the formation of hybrid micelles and the localization of Mo(132) in the micelle cores. The micelles exhibit a high stability despite time and dilution. Furthermore, the fusion of the micelles can be readily adjusted by varying the length of PS blocks, which is promising to be used in constructing polymer-POM hybrid materials with discrete or continuous hybrid domains. This work is based on the electrostatic premodification of POMs and thus its concept is generally suitable for the whole anionic POM system, which may create a large class of BC-POM nanocomposites with tunable structures.

  2. Controlled self-assembly of conjugated rod-coil block copolymers for applications in organic optoelectronics

    NASA Astrophysics Data System (ADS)

    Tao, Yuefei

    Organic electronics are of great interest in manufacturing light weight, mechanical flexible, and inexpensive large area devices. While significant improvements have been made over the last several years and it is now clear that morphology on the lengthscale of exciton diffusion (10nm) is of crucial importance, a clear relationship between structure and device properties has not emerged. This lack of understanding largely emerges from an inability to control morphology on this lengthscale. This thesis will center around an approach, based on block copolymer self-assembly, to generate equilibrium nanostructures on the 10 nm lengthscale of exciton diffusion and study their effects on device performance. Self-assembly of semiconducting block copolymers is complicated by the non-classical chain shape of conjugated polymers. Unlike classical polymers, the chains do not assume a Gaussian coil shape which is stretched near block copolymer interfaces, instead the chains are elongated and liquid crystalline. Previous work has demonstrated how these new molecular interactions and shapes control the phase diagram of so-called rod-coil block copolymers. Here, we will focus on controlling domain size, orientation, and chemical structure. While domain size can be controlled directly through molecular weight, this requires significant additional synthesis of domain size is to be varied. Here, the domain size is controlled by blending homopolymers into a self-assembling rod-coil block copolymer. When coil-like blocks are incorporated, the domains swell, as expected. When rod-like blocks are incorporated, they interdigitate with the rods of the block copolymers. This results in an increase in interfacial area which forces the coils to rearrange and an overall decrease in domain size with increasing rod content. Control over lamellar orientation is crucial in order to design and control charge transport pathways and exciton recombination or separation interfaces. While numerous techniques have been demonstrated for classical block copolymers, the pi conjugation in the rod blocks allow for additional control mechanisms. Liquid crystals are traditionally aligned in magnetic fields. Here, it is demonstrated that if the rod-like blocks are aligned unidirectionally, the block copolymer interfaces follow to create macroscopic alignment of the nanostructures. Organic Light Emitting Diodes (OLEDs) are generally composed of electron transporting and hole transporting moieties to balance charge recombination. Here, a new multifunctional bipolar rod-coil block copolymer containing the hole transporting and electron transporting materials is synthesized. Self-assembly of this new block copolymer results in 15nm lamellae oriented in grains both parallel and perpendicula to the anode. The self-assembled block copolymer shows superior device performance to controls consisting of a luminescent, analogous homopolymer, and a blend of the two component homopolymers. The effects of the morphologies and chemical structure on photovoltaics is explored with a rod-coil block copolymer, (poly(3-hexylthiophene-b-acrylic perylene)). By varying the kinetics of self-assembly through processing, the block copolymer can be disordered, ordered with only short range registry between the nanodomains, or with long-range order. The short range ordered samples showed the best device performance suggesting that the connectivity that is a biproduct of poor order is beneficial for device performance.

  3. 15 CFR 50.40 - Fee structure for statistics for city blocks in the 1980 Census of Population and Housing.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 15 Commerce and Foreign Trade 1 2011-01-01 2011-01-01 false Fee structure for statistics for city... SERVICES AND STUDIES BY THE BUREAU OF THE CENSUS § 50.40 Fee structure for statistics for city blocks in... for each city block, drawn from the subjects which are being covered on a 100-percent basis. For these...

  4. 15 CFR 50.40 - Fee structure for statistics for city blocks in the 1980 Census of Population and Housing.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 15 Commerce and Foreign Trade 1 2010-01-01 2010-01-01 false Fee structure for statistics for city... SERVICES AND STUDIES BY THE BUREAU OF THE CENSUS § 50.40 Fee structure for statistics for city blocks in... for each city block, drawn from the subjects which are being covered on a 100-percent basis. For these...

  5. A reuse-based framework for the design of analog and mixed-signal ICs

    NASA Astrophysics Data System (ADS)

    Castro-Lopez, Rafael; Fernandez, Francisco V.; Rodriguez Vazquez, Angel

    2005-06-01

    Despite the spectacular breakthroughs of the semiconductor industry, the ability to design integrated circuits (ICs) under stringent time-to-market (TTM) requirements is lagging behind integration capacity, so far keeping pace with still valid Moore"s Law. The resulting gap is threatening with slowing down such a phenomenal growth. The design community believes that it is only by means of powerful CAD tools and design methodologies - and, possibly, a design paradigm shift - that this design gap can be bridged. In this sense, reuse-based design is seen as a promising solution, and concepts such as IP Block, Virtual Component, and Design Reuse have become commonplace thanks to the significant advances in the digital arena. Unfortunately, the very nature of analog and mixed-signal (AMS) design has hindered a similar level of consensus and development. This paper presents a framework for the reuse-based design of AMS circuits. The framework is founded on three key elements: (1) a CAD-supported hierarchical design flow that facilitates the incorporation of AMS reusable blocks, reduces the overall design time, and expedites the management of increasing AMS design complexity; (2) a complete, clear definition of the AMS reusable block, structured into three separate facets or views: the behavioral, structural, and layout facets, the two first for top-down electrical synthesis and bottom-up verification, the latter used during bottom-up physical synthesis; (3) the design for reusability set of tools, methods, and guidelines that, relying on intensive parameterization as well as on design knowledge capture and encapsulation, allows to produce fully reusable AMS blocks. A case study and a functional silicon prototype demonstrate the validity of the paper"s proposals.

  6. NEUTRON-IRRADIATED STRUCTURES

    DOEpatents

    Ashley, E.L.; Ashley, J.W.; Bowker, H.W.; Hall, R.H.; Kendall, J.W.

    1959-02-01

    A moderator structure is described for a nuclear reactor of the heterogensous type wherein a large mass of moderator is provided with channels therethrough for the introduction of uranium serving as nuclear fuel and for the passage of a cooling fluid. The structure is comprised of blocks of moderator material in superposed horizontal layers, the blocks of each layer being tied together with spaces between them and oriented to have horizontal Wigner growth. The ties are strips of moderator material, the same as the blocks, with transverse Wigner growth, disposed horizontally along lines crossing at vertical axes of the blocks. The blocks are preferably rectangular with a larger or length dimension transverse to the directions of Wiguer growth and are stood on end to provide for horizontal growth.

  7. Enhancing instruction scheduling with a block-structured ISA

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

    Melvin, S.; Patt, Y.

    It is now generally recognized that not enough parallelism exists within the small basic blocks of most general purpose programs to satisfy high performance processors. Thus, a wide variety of techniques have been developed to exploit instruction level parallelism across basic block boundaries. In this paper we discuss some previous techniques along with their hardware and software requirements. Then we propose a new paradigm for an instruction set architecture (ISA): block-structuring. This new paradigm is presented, its hardware and software requirements are discussed and the results from a simulation study are presented. We show that a block-structured ISA utilizes bothmore » dynamic and compile-time mechanisms for exploiting instruction level parallelism and has significant performance advantages over a conventional ISA.« less

  8. Domino structures evolution in strike-slip shear zones; the importance of the cataclastic flow

    NASA Astrophysics Data System (ADS)

    Moreira, N.; Dias, R.

    2018-05-01

    The Porto-Tomar-Ferreira do Alentejo dextral Shear Zone is one of the most important structures of the Iberian Variscides. In its vicinity, close to Abrantes (Central Portugal), a localized heterogeneous strain pattern developed in a decimetric metamorphic siliceous multilayer. This complex pattern was induced by the D2 dextral shearing of the early S0//S1 foliation in brittle-ductile conditions, giving rise to three main shear zone families. One of these families, with antithetic kinematics, delimits blocks with rigid clockwise rotation surrounded by coeval cataclasites, generating a local domino structure. The proposed geometrical and kinematic analysis, coupled with statistical studies, highlights the relation between subsidiary shear zones and the main shear zone. Despite the heterogeneous strain pattern, a quantitative approach of finite strain was applied based on the restoration of the initial fracture pattern. This approach shows the importance of the cataclastic flow coupled with the translational displacement of the domino domain in solving space problems related to the rigid block rotation. Such processes are key in allowing the rigid block rotation inside shear zones whenever the simple shear component is a fundamental mechanism.

  9. Structural design of ketal and acetal blocking groups in two-component chemically amplified positive DUV resists

    NASA Astrophysics Data System (ADS)

    Mertesdorf, Carlo; Muenzel, Norbert; Holzwarth, Heinz E.; Falcigno, Pasquale A.; Schacht, Hans-Thomas; Rohde, Ottmar; Schulz, Reinhard; Slater, Sydney G.; Frey, David; Nalamasu, Omkaram; Timko, Allen G.; Neenan, Thomas X.

    1995-06-01

    In the present study, protecting groups of moderate stability, such as acetals and ketals, were investigated as pendant blocking groups in polyvinyl phenols. Polymers were obtained by reacting enol ethers with the phenolic side groups to form acetal or ketal blocked phenols. Decomposition temperatures, glass transition temperatures, and molecular weights of the resulting polymers were monitored and correlated with the protecting group structure. Stability of the protecting groups can be explained by protonation occurring at either of the two oxygen sites, making two cleavage routes possible. Secondary reactions of the released protecting groups in the resist film were investigated and discussed. The structure of the protecting group was designed in order to meet basic resist properties such as resolution/linearity, DOF, post exposure delay latitude and thermal stability. A Canon FPA 4500 (NA equals 0.37) and a GCA XLS exposure tool (NA equals 0.53) were used for the optimization process. A preoptimized resist formulation based on the above criteria exhibits 0.23 micrometers line/space resolution, 0.8 micrometers focus latitude at 0.25 micrometers resolution and approximately two hours post exposure delay latitude.

  10. Unraveling the Agglomeration Mechanism in Charged Block Copolymer and Surfactant Complexes

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

    Borreguero, Jose M.; Pincus, Philip A.; Sumpter, Bobby G.

    Here, we report a molecular dynamics simulation investigation of self-assembly and complex formation of charged-neutral double hydrophilic and hydrophobic-hydrophilic block copolymers (BCP) with oppositely charged surfactants. Furthermore, the structure of the surfactant micelles and the BCP aggregation on the micelle surface is systematically studied for five different BCP volume fractions that also mimics a reduction of the surfactant concentration. The local electrostatic interactions between the oppositely charged species encourage the formation of core-shell structures between the surfactant micelles where the surfactants form the cores and the charged blocks of the BCP form the corona. The emergent morphologies of these aggregatesmore » are contingent upon the nature of the BCP neutral blocks. The hydrophilic neutral blocks agglomerate with the micelles as hairy colloidal structures while the hydrophobic neutrals agglomerate in lamellar structures with the surfactant micelles. The distribution of counterion charges along the simulation box show a close-to-normal density distribution for the hydrophilic neutral blocks and a binodal distribution for hydrophobic neutral blocks. No specific surfactant concentration dependent scaling relation is observed as opposed to the simpler case of homo-polyelectrolytes.« less

  11. Unraveling the Agglomeration Mechanism in Charged Block Copolymer and Surfactant Complexes

    DOE PAGES

    Borreguero, Jose M.; Pincus, Philip A.; Sumpter, Bobby G.; ...

    2017-01-27

    Here, we report a molecular dynamics simulation investigation of self-assembly and complex formation of charged-neutral double hydrophilic and hydrophobic-hydrophilic block copolymers (BCP) with oppositely charged surfactants. Furthermore, the structure of the surfactant micelles and the BCP aggregation on the micelle surface is systematically studied for five different BCP volume fractions that also mimics a reduction of the surfactant concentration. The local electrostatic interactions between the oppositely charged species encourage the formation of core-shell structures between the surfactant micelles where the surfactants form the cores and the charged blocks of the BCP form the corona. The emergent morphologies of these aggregatesmore » are contingent upon the nature of the BCP neutral blocks. The hydrophilic neutral blocks agglomerate with the micelles as hairy colloidal structures while the hydrophobic neutrals agglomerate in lamellar structures with the surfactant micelles. The distribution of counterion charges along the simulation box show a close-to-normal density distribution for the hydrophilic neutral blocks and a binodal distribution for hydrophobic neutral blocks. No specific surfactant concentration dependent scaling relation is observed as opposed to the simpler case of homo-polyelectrolytes.« less

  12. Phase Behavior of a Single Structured Ionomer Chain in Solution

    DOE PAGES

    Aryal, Dipak; Etampawala, Thusitha; Perahia, Dvora; ...

    2014-08-14

    Structured polymers offer a means to tailor transport pathways within mechanically stable manifolds. Here we examine the building block of such a membrane, namely a single large pentablock co-polymer that consist of a center block of a randomly sulfonated polystyrene, designed for transport, tethered to poly-ethylene-r-propylene and end-capped by poly-t-butyl styrene, for mechanical stability,using molecular dynamics simulations. The polymer structure in a cyclohexane-heptane mixture, a technologically viable solvent, and in water, a poor solvent for all segments and a ubiquitous substance is extracted. In all solvents the pentablock collapsed into nearly spherical aggregates where the ionic block is segregated. Inmore » hydrophobic solvents, the ionic block resides in the center, surrounded by swollen intermix of flexible and end blocks. In water all blocks are collapsed with the sulfonated block residing on the surface. Our results demonstrate that solvents drive different local nano-segregation, providing a gateway to assemble membranes with controlled topology.« less

  13. Resilient self-assembling hydrogels from block copolypeptide amphiphiles

    NASA Astrophysics Data System (ADS)

    Nowak, Andrew Paul

    The ability to produce well defined synthetic polypeptides has been greatly improved by the discovery of transition metal species that mediate the controlled polymerization of N-carboxyanhydrides (NCAs). These metal species create a living polymerization system by producing control over chain length, low polydispersities, and the ability to form complex block architectures. We have applied this system to the synthesis of block copolypeptide amphiphiles. Initial block copolymers synthesized were composed of hydrophilic, cationic poly(L-Lysine) combined with hydrophobic, alpha-helical poly(L-Leucine). These Lysine- block-Leucine copolypeptides were found to form stiff, clear hydrogels at low concentration (˜1 wt%) in low ionic strength water. Based on this unexpected result we used the flexibility of our transition metal polymerization chemistry to better understand the nature and mechanisms of gel formation in these materials. Systematic changes to the original Lysine-block-Leucine copolypeptides were made by altering overall chain size, relative block length, polyelectrolyte charge, and hydrophobic secondary structure. Rheological characterization revealed that the strength of these hydrogels was primarily dependent on degree of polymerization, relative block length, and a well ordered secondary structure in the hydrophobic segment. The Lysine-block-Leucine hydrogels were formed by direct addition of water to dry polypeptide material which swelled to homogeneously fill the entire volume of liquid with no special processing. CryoTEM showed a percolating cellular network at ˜100nm that appears to be comprised of both membranes and fibers. Larger length scales studied with Laser Scanning Confocal Microscopy revealed a spontaneously formed microporous network with large (˜10mum) water rich voids. These hydrogels also displayed interesting mechanical properties including rapid recovery of solid like behavior after being sheared to a liquid and mechanical stability with increased temperature (˜90°C). The behavior of the Lysine- block-Leucine system with salt was also thoroughly investigated. With proper tuning of the relative block composition it was found that hydrogels could be optimized to possess good solubility and mechanical strength in many useful ionic solutions (˜100--200mM) such as pH buffers and cell culture media.

  14. Structural implications of weak Ca2+ block in Drosophila cyclic nucleotide-gated channels.

    PubMed

    Lam, Yee Ling; Zeng, Weizhong; Derebe, Mehabaw Getahun; Jiang, Youxing

    2015-09-01

    Calcium permeability and the concomitant calcium block of monovalent ion current ("Ca(2+) block") are properties of cyclic nucleotide-gated (CNG) channel fundamental to visual and olfactory signal transduction. Although most CNG channels bear a conserved glutamate residue crucial for Ca(2+) block, the degree of block displayed by different CNG channels varies greatly. For instance, the Drosophila melanogaster CNG channel shows only weak Ca(2+) block despite the presence of this glutamate. We previously constructed a series of chimeric channels in which we replaced the selectivity filter of the bacterial nonselective cation channel NaK with a set of CNG channel filter sequences and determined that the resulting NaK2CNG chimeras displayed the ion selectivity and Ca(2+) block properties of the parent CNG channels. Here, we used the same strategy to determine the structural basis of the weak Ca(2+) block observed in the Drosophila CNG channel. The selectivity filter of the Drosophila CNG channel is similar to that of most other CNG channels except that it has a threonine at residue 318 instead of a proline. We constructed a NaK chimera, which we called NaK2CNG-Dm, which contained the Drosophila selectivity filter sequence. The high resolution structure of NaK2CNG-Dm revealed a filter structure different from those of NaK and all other previously investigated NaK2CNG chimeric channels. Consistent with this structural difference, functional studies of the NaK2CNG-Dm chimeric channel demonstrated a loss of Ca(2+) block compared with other NaK2CNG chimeras. Moreover, mutating the corresponding threonine (T318) to proline in Drosophila CNG channels increased Ca(2+) block by 16 times. These results imply that a simple replacement of a threonine for a proline in Drosophila CNG channels has likely given rise to a distinct selectivity filter conformation that results in weak Ca(2+) block. © 2015 Lam et al.

  15. Coastal protection using topological interlocking blocks

    NASA Astrophysics Data System (ADS)

    Pasternak, Elena; Dyskin, Arcady; Pattiaratchi, Charitha; Pelinovsky, Efim

    2013-04-01

    The coastal protection systems mainly rely on the self-weight of armour blocks to ensure its stability. We propose a system of interlocking armour blocks, which form plate-shape assemblies. The shape and the position of the blocks are chosen in such a way as to impose kinematic constraints that prevent the blocks from being removed from the assembly. The topological interlocking shapes include simple convex blocks such as platonic solids, the most practical being tetrahedra, cubes and octahedra. Another class of topological interlocking blocks is so-called osteomorphic blocks, which form plate-like assemblies tolerant to random block removal (almost 25% of blocks need to be removed for the assembly to loose integrity). Both classes require peripheral constraint, which can be provided either by the weight of the blocks or post-tensioned internal cables. The interlocking assemblies provide increased stability because lifting one block involves lifting (and bending) the whole assembly. We model the effect of interlocking by introducing an equivalent additional self-weight of the armour blocks. This additional self-weight is proportional to the critical pressure needed to cause bending of the interlocking assembly when it loses stability. Using beam approximation we find an equivalent stability coefficient for interlocking. It is found to be greater than the stability coefficient of a structure with similar blocks without interlocking. In the case when the peripheral constraint is provided by the weight of the blocks and for the slope angle of 45o, the effective stability coefficient for a structure of 100 blocks is 33% higher than the one for a similar structure without interlocking. Further increase in the stability coefficient can be reached by a specially constructed peripheral constraint system, for instance by using post-tension cables.

  16. Efficient block processing of long duration biotelemetric brain data for health care monitoring

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

    Soumya, I.; Zia Ur Rahman, M., E-mail: mdzr-5@ieee.org; Rama Koti Reddy, D. V.

    In real time clinical environment, the brain signals which doctor need to analyze are usually very long. Such a scenario can be made simple by partitioning the input signal into several blocks and applying signal conditioning. This paper presents various block based adaptive filter structures for obtaining high resolution electroencephalogram (EEG) signals, which estimate the deterministic components of the EEG signal by removing noise. To process these long duration signals, we propose Time domain Block Least Mean Square (TDBLMS) algorithm for brain signal enhancement. In order to improve filtering capability, we introduce normalization in the weight update recursion of TDBLMS,more » which results TD-B-normalized-least mean square (LMS). To increase accuracy and resolution in the proposed noise cancelers, we implement the time domain cancelers in frequency domain which results frequency domain TDBLMS and FD-B-Normalized-LMS. Finally, we have applied these algorithms on real EEG signals obtained from human using Emotive Epoc EEG recorder and compared their performance with the conventional LMS algorithm. The results show that the performance of the block based algorithms is superior to the LMS counter-parts in terms of signal to noise ratio, convergence rate, excess mean square error, misadjustment, and coherence.« less

  17. A Motion Detection Algorithm Using Local Phase Information

    PubMed Central

    Lazar, Aurel A.; Ukani, Nikul H.; Zhou, Yiyin

    2016-01-01

    Previous research demonstrated that global phase alone can be used to faithfully represent visual scenes. Here we provide a reconstruction algorithm by using only local phase information. We also demonstrate that local phase alone can be effectively used to detect local motion. The local phase-based motion detector is akin to models employed to detect motion in biological vision, for example, the Reichardt detector. The local phase-based motion detection algorithm introduced here consists of two building blocks. The first building block measures/evaluates the temporal change of the local phase. The temporal derivative of the local phase is shown to exhibit the structure of a second order Volterra kernel with two normalized inputs. We provide an efficient, FFT-based algorithm for implementing the change of the local phase. The second processing building block implements the detector; it compares the maximum of the Radon transform of the local phase derivative with a chosen threshold. We demonstrate examples of applying the local phase-based motion detection algorithm on several video sequences. We also show how the locally detected motion can be used for segmenting moving objects in video scenes and compare our local phase-based algorithm to segmentation achieved with a widely used optic flow algorithm. PMID:26880882

  18. Structure from Motion

    DTIC Science & Technology

    1988-11-17

    NOTATION 17. COSATI CODES 18. SUBJECT TERMS (Continue on reverse if ntcestary and identify by block number) FIELD GROUP SUB-GROUP ,-.:image...ambiguity in the recognition of partially occluded objects. V 1 , t : ., , ’ -, L: \\ : _ 20. DISTRIBUTION/AVAILABILITY OF ABSTRACT 21. ABSTRACT...constraints involved in the problem. More information can be found in [ 1 ]. Motion-based segmentation. Edge detection algorithms based on visual motion

  19. Influence of topographically patterned angled guidelines on directed self-assembly of block copolymers

    NASA Astrophysics Data System (ADS)

    Rebello, Nathan; Sethuraman, Vaidyanathan; Blachut, Gregory; Ellison, Christopher J.; Willson, C. Grant; Ganesan, Venkat

    2017-11-01

    Single chain in mean-field Monte Carlo simulations were employed to study the self-assembly of block copolymers (BCP) in thin films that use trapezoidal guidelines to direct the orientation and alignment of lamellar patterns. The present study explored the influence of sidewall interactions and geometry of the trapezoidal guidelines on the self-assembly of perpendicularly oriented lamellar morphologies. When both the sidewall and the top surface exhibit preferential interactions to the same block of the BCP, trapezoidal guidelines with intermediate taper angles were found to result in less defective perpendicularly orientated morphologies. Similarly, when the sidewall and top surface are preferential to distinct blocks of the BCP, intermediate tapering angles were found to be optimal in promoting defect free structures. Such results are rationalized based on the energetics arising in the formation of perpendicularly oriented lamella on patterned substrates.

  20. [Present status and trend of heart fluid mechanics research based on medical image analysis].

    PubMed

    Gan, Jianhong; Yin, Lixue; Xie, Shenghua; Li, Wenhua; Lu, Jing; Luo, Anguo

    2014-06-01

    With introduction of current main methods for heart fluid mechanics researches, we studied the characteristics and weakness for three primary analysis methods based on magnetic resonance imaging, color Doppler ultrasound and grayscale ultrasound image, respectively. It is pointed out that particle image velocity (PIV), speckle tracking and block match have the same nature, and three algorithms all adopt block correlation. The further analysis shows that, with the development of information technology and sensor, the research for cardiac function and fluid mechanics will focus on energy transfer process of heart fluid, characteristics of Chamber wall related to blood fluid and Fluid-structure interaction in the future heart fluid mechanics fields.

  1. Cascade process modeling with mechanism-based hierarchical neural networks.

    PubMed

    Cong, Qiumei; Yu, Wen; Chai, Tianyou

    2010-02-01

    Cascade process, such as wastewater treatment plant, includes many nonlinear sub-systems and many variables. When the number of sub-systems is big, the input-output relation in the first block and the last block cannot represent the whole process. In this paper we use two techniques to overcome the above problem. Firstly we propose a new neural model: hierarchical neural networks to identify the cascade process; then we use serial structural mechanism model based on the physical equations to connect with neural model. A stable learning algorithm and theoretical analysis are given. Finally, this method is used to model a wastewater treatment plant. Real operational data of wastewater treatment plant is applied to illustrate the modeling approach.

  2. Gyroid structure via highly asymmetric ABC and AB blends

    NASA Astrophysics Data System (ADS)

    Ahn, Seonghyeon; Kwak, Jongheon; Choi, Chungryong; Kim, Jin Kon

    Gyroid structures are very important because of their co-continuous and network structures. However, a block copolymer shows gyroid structures only at 35 % volume fraction of one block. In this study, we designed ABC/AB blend system. B (polystyrene (PS)) is the matrix, while A (polyisoprene (PI)) and C (poly(2-vinyl pridine (P2VP)) are the core part. This blend shows gyroid structures at 20 % volume fraction, that is smaller than that observed at diblock copolymer. Morphologies of neat block copolymers and blends were characterized by TEM and small angle X-ray scattering.

  3. Role of the electron blocking layer in the graded-index separate confinement heterostructure nitride laser diodes

    NASA Astrophysics Data System (ADS)

    Bojarska, Agata; Goss, Jakub; Stanczyk, Szymon; Makarowa, Irina; Schiavon, Dario; Czernecki, Robert; Suski, Tadeusz; Perlin, Piotr

    2018-04-01

    In this work, we investigate the role of the electron blocking layer (EBL) in laser diodes based on a graded index separate confinement heterostructure. We compare two sets of devices with very different EBL aluminum composition (3% and 12%) and design (graded and superlattice). The results of electro-optical characterization of these laser diodes reveal surprisingly modest role of electron blocking layer composition in determination of the threshold current and the differential efficiency values. However, EBL structure influences the operating voltage, which is decreased for devices with lower EBL and superlattice EBL. We observe also the differences in the thermal stability of devices - characteristic temperature is lower for lasers with 3% Al in EBL.

  4. Preferential Nucleosome Assembly at DNA Triplet Repeats from the Myotonic Dystrophy Gene

    NASA Astrophysics Data System (ADS)

    Wang, Yuh-Hwa; Amirhaeri, Sorour; Kang, Seongman; Wells, Robert D.; Griffith, Jack D.

    1994-07-01

    The expansion of CTG repeats in DNA occurs in or near genes involved in several human diseases, including myotonic dystrophy and Huntington's disease. Nucleosomes, the basic structural element of chromosomes, consist of 146 base pairs of DNA coiled about an octamer of histone proteins and mediate general transcriptional repression. Electron microscopy was used to examine in vitro the nucleosome assembly of DNA containing repeating CTG triplets. The efficiency of nucleosome formation increased with expanded triplet blocks, suggesting that such blocks may repress transcription through the creation of stable nucleosomes.

  5. Dielectric properties of betaine phosphite and deuterated betaine phosphite films

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

    Balashova, E. V., E-mail: balashova@mail.ioffe.ru; Krichevtsov, B. B.; Zaitseva, N. V.

    2011-01-15

    Polycrystalline films of betaine phosphite (BPI) and deuterated BPI have been grown by evaporation on LiNbO{sub 3}, {alpha}-SiO{sub 2}, {alpha}-Al{sub 2}O{sub 3}, and NdGaO{sub 3} substrates. These films consist of large single-crystal blocks in which the polar axis (b) lies in the substrate plane. The results of studying the dielectric properties of the films using interdigital electrodes, X-ray diffraction, and block images in a polarized-light microscope in reflection are reported. The film transition into the ferroelectric state at T = T{sub c} is accompanied by strong anomalies of the capacitance of the film/interdigital structure/substrate structure. The deuteration of BPI filmsmore » leads to an increase in their temperature T{sub c}: from T{sub c} = 200 K for BPI-based structures to T{sub c} = 280 K for structures with a high degree of deuteration (d {approx} 90%).« less

  6. Design development of graphite primary structures enables SSTO success

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

    Biagiotti, V.A.; Yahiro, J.S.; Suh, D.E.

    1997-01-01

    This paper describes the development of a graphite composite wing and a graphite composite intertank primary structure for application toward Single-Stage to Orbit space vehicles such as those under development in NASA{close_quote}s X-33/Reusable Launch Vehicle (RLV) Program. The trade study and designs are based on a Rockwell vertical take-off and horizontal landing (VTHL) wing-body RLV vehicle. Northrop Grumman{close_quote}s approach using a building block development technique is described. Composite Graphite/Bismaleimide (Gr/BMI) material characterization test results are presented. Unique intertank and wing composite subcomponent test article designs are described and test results to date are presented. Wing and intertank Full Scale Sectionmore » Test Article (FSTA) objectives and designs are outlined. Trade studies, supporting building block testing, and FSTA demonstrations combine to develop graphite primary structure composite technology that enables developing X-33/RLV design programs to meet critical SSTO structural weight and operations performance criteria. {copyright} {ital 1997 American Institute of Physics.}« less

  7. Late-Paleozoic-Mesozoic deformational and deformation related metamorphic structures of Kuznetsk-Altai region

    NASA Astrophysics Data System (ADS)

    Zinoviev, Sergei

    2014-05-01

    Kuznetsk-Altai region is a part of the Central Asian Orogenic Belt. The nature and formation mechanisms of the observed structure of Kuznetsk-Altai region are interpreted by the author as the consequence of convergence of Tuva-Mongolian and Junggar lithospheric block structures and energy of collision interaction between the blocks of crust in Late-Paleozoic-Mesozoic period. Tectonic zoning of Kuznetsk-Altai region is based on the principle of adequate description of geological medium (without methods of 'primary' state recovery). The initial indication of this convergence is the crust thickening in the zone of collision. On the surface the mechanisms of lateral compression form a regional elevation; with this elevation growth the 'mountain roots' start growing. With an approach of blocks an interblock elevation is divided into various fragments, and these fragments interact in the manner of collision. The physical expression of collision mechanisms are periodic pulses of seismic activity. The main tectonic consequence of the block convergence and collision of interblock units is formation of an ensemble of regional structures of the deformation type on the basis of previous 'pre-collision' geological substratum [Chikov et al., 2012]. This ensemble includes: 1) allochthonous and autochthonous blocks of weakly deformed substratum; 2) folded (folded-thrust) systems; 3) dynamic metamorphism zones of regional shears and main faults. Characteristic of the main structures includes: the position of sedimentary, magmatic and PT-metamorphic rocks, the degree of rock dynamometamorphism and variety rock body deformation, as well as the styles and concentrations of mechanic deformations. 1) block terranes have weakly elongated or isometric shape in plane, and they are the systems of block structures of pre-collision substratum separated by the younger zones of interblock deformations. They stand out among the main deformation systems, and the smallest are included into the deformation systems. 2) folded (folded-thrust) deformation systems combine deformation zones with relic lenses of Paleozoid substratum, and predominantly conform systems of the main faults. Despite a high degree of regional deformation the sedimentary-stratified and intrusive-contact relations of geological bodies are stored within the deformation systems, and this differs in the main the collision systems from zones of dynamic metamorphism. 3) regional zones of dynamic metamorphism of Kuznetsk-Altai region are the concentration belts of multiple mechanic deformations and contrast dynamometamorphism of complexes. The formational basis of dynamic metamorphism zones is tectonites of the collision stage. Zones of dynamic metamorphism attract special attention in the structural model of Kuznetsk-Altai region. They not only form the typical tectonic framework of collision sutures, but also contain the main part of ore deposits of this region. Pulse mode of structure formation of Kuznetsk-Altai region is detected. Major collision events in Kuznetsk-Altai region were in the late-Carboniferous-Triassic time (307-310, 295-285, 260-250 and 240-220 Ma). This study was supported by a grant of the Russian Foundation for Basic Research (project nos. 14-05-00117).

  8. Vision-Based Precision Landings of a Tailsitter UAV

    DTIC Science & Technology

    2010-04-01

    2.2: Schematic of the controller used in simulation. The block diagram shown in Figure 2.2 shows the simulation structure used to simulate the vision...the structure of the flight facility walls, any vibration applied to the structure would potentially change the pose of the cameras. Each camera’s pose...relative to the target in Chap- ter 4, a flat earth assumption was made. In several situations the approximation that the ground over which the UAV is

  9. Comparative study of CAVET with dielectric and p-GaN gate and Mg ion-implanted current blocking layer

    NASA Astrophysics Data System (ADS)

    Mandal, Saptarshi; Agarwal, Anchal; Ahmadi, Elaheh; Mahadeva Bhat, K.; Laurent, Matthew A.; Keller, Stacia; Chowdhury, Srabanti

    2017-08-01

    In this work, a study of two different types of current aperture vertical electron transistor (CAVET) with ion-implanted blocking layer are presented. The device fabrication and performance limitation of a CAVET with a dielectric gate is discussed, and the breakdown limiting structure is evaluated using on-wafer test structures. The gate dielectric limited the device breakdown to 50V, while the blocking layer was able to withstand over 400V. To improve the device performance, an alternative CAVET structure with a p-GaN gate instead of dielectric is designed and realized. The pGaN gated CAVET structure increased the breakdown voltage to over 400V. Measurement of test structures on the wafer showed the breakdown was limited by the blocking layer instead of the gate p-n junction.

  10. Fast iterative solution of the Bethe-Salpeter eigenvalue problem using low-rank and QTT tensor approximation

    NASA Astrophysics Data System (ADS)

    Benner, Peter; Dolgov, Sergey; Khoromskaia, Venera; Khoromskij, Boris N.

    2017-04-01

    In this paper, we propose and study two approaches to approximate the solution of the Bethe-Salpeter equation (BSE) by using structured iterative eigenvalue solvers. Both approaches are based on the reduced basis method and low-rank factorizations of the generating matrices. We also propose to represent the static screen interaction part in the BSE matrix by a small active sub-block, with a size balancing the storage for rank-structured representations of other matrix blocks. We demonstrate by various numerical tests that the combination of the diagonal plus low-rank plus reduced-block approximation exhibits higher precision with low numerical cost, providing as well a distinct two-sided error estimate for the smallest eigenvalues of the Bethe-Salpeter operator. The complexity is reduced to O (Nb2) in the size of the atomic orbitals basis set, Nb, instead of the practically intractable O (Nb6) scaling for the direct diagonalization. In the second approach, we apply the quantized-TT (QTT) tensor representation to both, the long eigenvectors and the column vectors in the rank-structured BSE matrix blocks, and combine this with the ALS-type iteration in block QTT format. The QTT-rank of the matrix entities possesses almost the same magnitude as the number of occupied orbitals in the molecular systems, No

  11. Lateral variations of thermo-rheological structure in SE Tibet

    NASA Astrophysics Data System (ADS)

    Jiang, X.; Gong, W.

    2017-12-01

    The structure and geodynamics in SE Tibet is important to developing a full understanding of tectonic evolution of the Tibetan plateau. To investigate the lithospheric structure and deformation, we present thermo-rheological models for two transects across SE Tibet. The thermal models are determined by the heat flow and P-wave velocity models. Based on thermal models, the rheological models are constructed in the weak and strong cases where the lower crust is felsic or mafic granulite and the lithospheric mantle is wet or dry peridotite. The thermal models show an obvious high-temperature anomaly within the lithosphere beneath the Chuandian block. Strong lateral heterogeneity is present in the rheological modeling and corresponds to variations of thermal models. The Chuandian block demonstrates a lower level of lithospheric strength than its neighboring regions, which is in accord with the seismogenic layer distribution. Combining with a joint analysis of SKS splitting and GPS data, the crust and mantle is decoupled at a depth below the topmost mantle in SE Tibet. The strong crust beneath the South China plate and Indochina block has two brittle load-bearing layers in the crust, indicating the system is mechanically coupled. The crust beneath the Emeishan igneous province also has two brittle load-bearing layers, but the brittle deformation is restricted to the topmost 10 km of the upper and lower crust. In contrast, only one brittle load-bearing layer resides in the upper crust with the lower crust contributing little to the lithospheric strength at the location where low-velocity-high-conductivity zones have been recognized within the crust in the Chuandian block. This indicates that the crust beneath the Chuandian block becomes decoupled, as evidenced by the crustal anisotropy pattern.

  12. An interplay of fusiform gyrus and hippocampus enables prototype- and exemplar-based category learning.

    PubMed

    Lech, Robert K; Güntürkün, Onur; Suchan, Boris

    2016-09-15

    The aim of the present study was to examine the contributions of different brain structures to prototype- and exemplar-based category learning using functional magnetic resonance imaging (fMRI). Twenty-eight subjects performed a categorization task in which they had to assign prototypes and exceptions to two different families. This test procedure usually produces different learning curves for prototype and exception stimuli. Our behavioral data replicated these previous findings by showing an initially superior performance for prototypes and typical stimuli and a switch from a prototype-based to an exemplar-based categorization for exceptions in the later learning phases. Since performance varied, we divided participants into learners and non-learners. Analysis of the functional imaging data revealed that the interaction of group (learners vs. non-learners) and block (Block 5 vs. Block 1) yielded an activation of the left fusiform gyrus for the processing of prototypes, and an activation of the right hippocampus for exceptions after learning the categories. Thus, successful prototype- and exemplar-based category learning is associated with activations of complementary neural substrates that constitute object-based processes of the ventral visual stream and their interaction with unique-cue representations, possibly based on sparse coding within the hippocampus. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Compressed-Sensing Reconstruction Based on Block Sparse Bayesian Learning in Bearing-Condition Monitoring

    PubMed Central

    Sun, Jiedi; Yu, Yang; Wen, Jiangtao

    2017-01-01

    Remote monitoring of bearing conditions, using wireless sensor network (WSN), is a developing trend in the industrial field. In complicated industrial environments, WSN face three main constraints: low energy, less memory, and low operational capability. Conventional data-compression methods, which concentrate on data compression only, cannot overcome these limitations. Aiming at these problems, this paper proposed a compressed data acquisition and reconstruction scheme based on Compressed Sensing (CS) which is a novel signal-processing technique and applied it for bearing conditions monitoring via WSN. The compressed data acquisition is realized by projection transformation and can greatly reduce the data volume, which needs the nodes to process and transmit. The reconstruction of original signals is achieved in the host computer by complicated algorithms. The bearing vibration signals not only exhibit the sparsity property, but also have specific structures. This paper introduced the block sparse Bayesian learning (BSBL) algorithm which works by utilizing the block property and inherent structures of signals to reconstruct CS sparsity coefficients of transform domains and further recover the original signals. By using the BSBL, CS reconstruction can be improved remarkably. Experiments and analyses showed that BSBL method has good performance and is suitable for practical bearing-condition monitoring. PMID:28635623

  14. Efficient Blockwise Permutation Tests Preserving Exchangeability

    PubMed Central

    Zhou, Chunxiao; Zwilling, Chris E.; Calhoun, Vince D.; Wang, Michelle Y.

    2014-01-01

    In this paper, we present a new blockwise permutation test approach based on the moments of the test statistic. The method is of importance to neuroimaging studies. In order to preserve the exchangeability condition required in permutation tests, we divide the entire set of data into certain exchangeability blocks. In addition, computationally efficient moments-based permutation tests are performed by approximating the permutation distribution of the test statistic with the Pearson distribution series. This involves the calculation of the first four moments of the permutation distribution within each block and then over the entire set of data. The accuracy and efficiency of the proposed method are demonstrated through simulated experiment on the magnetic resonance imaging (MRI) brain data, specifically the multi-site voxel-based morphometry analysis from structural MRI (sMRI). PMID:25289113

  15. East Cameron Block 270, a Pleistocene field

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

    Holland, D.S.; Sutley, C.E.; Berlitz, R.E.

    1974-01-01

    Exploration of the Plio-Pleistocene in the Gulf of Mexico since 1970 has discovered significant hydrocarbon reserves. One of the better gas fields to date has been the Block 270 E. Cameron field. Utilization of a coordinated exploitation plan with Schlumberger has allowed Pennzoil as operator, to develop and put on production the Block 270 field in a minimum time period. Block 270 field is a N.-S. trending faulted nose at 6,000 ft. At G-Sand depth (8,700 ft), the structure has closed, forming an elongated N.-S. structure with dip in all directions from the Block 270 area. Closure is the resultmore » of contemporaneous growth on the E. bounding regional fault. Structural and stratigraphic interpretations from dipmeters were used to help determine the most favorable offset locations.« less

  16. Chain end distribution of block copolymer in two-dimensional microphase-separated structure studied by scanning near-field optical microscopy.

    PubMed

    Sekine, Ryojun; Aoki, Hiroyuki; Ito, Shinzaburo

    2009-10-01

    The chain end distribution of a block copolymer in a two-dimensional microphase-separated structure was studied by scanning near-field optical microscopy (SNOM). In the monolayer of poly(octadecyl methacrylate)-block-poly(isobutyl methacrylate) (PODMA-b-PiBMA), the free end of the PiBMA subchain was directly observed by SNOM, and the spatial distributions of the whole block and the chain end are examined and compared with the convolution of the point spread function of the microscope and distribution function of the model structures. It was found that the chain end distribution of the block copolymer confined in two dimensions has a peak near the domain center, being concentrated in the narrower region, as compared with three-dimensional systems.

  17. Dynamics of propagation of premature impulses in structurally remodeled infarcted myocardium: a computational analysis

    PubMed Central

    Cabo, Candido

    2014-01-01

    Initiation of cardiac arrhythmias typically follows one or more premature impulses either occurring spontaneously or applied externally. In this study, we characterize the dynamics of propagation of single (S2) and double premature impulses (S3), and the mechanisms of block of premature impulses at structural heterogeneities caused by remodeling of gap junctional conductance (Gj) in infarcted myocardium. Using a sub-cellular computer model of infarcted tissue, we found that |INa,max|, prematurity (coupling interval with the previous impulse), and conduction velocity (CV) of premature impulses change dynamically as they propagate away from the site of initiation. There are fundamental differences between the dynamics of propagation of S2 and S3 premature impulses: for S2 impulses |INa,max| recovers fast, prematurity decreases and CV increases as propagation proceeds; for S3 impulses low values of |INa,max| persist, prematurity could increase, and CV could decrease as impulses propagate away from the site of initiation. As a consequence it is more likely that S3 impulses block at sites of structural heterogeneities causing source/sink mismatch than S2 impulses block. Whether premature impulses block at Gj heterogeneities or not is also determined by the values of Gj (and the space constant λ) in the regions proximal and distal to the heterogeneity: when λ in the direction of propagation increases >40%, premature impulses could block. The maximum slope of CV restitution curves for S2 impulses is larger than for S3 impulses. In conclusion: (1) The dynamics of propagation of premature impulses make more likely that S3 impulses block at sites of structural heterogeneities than S2 impulses block; (2) Structural heterogeneities causing an increase in λ (or CV) of >40% could result in block of premature impulses; (3) A decrease in the maximum slope of CV restitution curves of propagating premature impulses is indicative of an increased potential for block at structural heterogeneities. PMID:25566085

  18. Dynamics of propagation of premature impulses in structurally remodeled infarcted myocardium: a computational analysis.

    PubMed

    Cabo, Candido

    2014-01-01

    Initiation of cardiac arrhythmias typically follows one or more premature impulses either occurring spontaneously or applied externally. In this study, we characterize the dynamics of propagation of single (S2) and double premature impulses (S3), and the mechanisms of block of premature impulses at structural heterogeneities caused by remodeling of gap junctional conductance (Gj) in infarcted myocardium. Using a sub-cellular computer model of infarcted tissue, we found that |INa,max|, prematurity (coupling interval with the previous impulse), and conduction velocity (CV) of premature impulses change dynamically as they propagate away from the site of initiation. There are fundamental differences between the dynamics of propagation of S2 and S3 premature impulses: for S2 impulses |INa,max| recovers fast, prematurity decreases and CV increases as propagation proceeds; for S3 impulses low values of |INa,max| persist, prematurity could increase, and CV could decrease as impulses propagate away from the site of initiation. As a consequence it is more likely that S3 impulses block at sites of structural heterogeneities causing source/sink mismatch than S2 impulses block. Whether premature impulses block at Gj heterogeneities or not is also determined by the values of Gj (and the space constant λ) in the regions proximal and distal to the heterogeneity: when λ in the direction of propagation increases >40%, premature impulses could block. The maximum slope of CV restitution curves for S2 impulses is larger than for S3 impulses. (1) The dynamics of propagation of premature impulses make more likely that S3 impulses block at sites of structural heterogeneities than S2 impulses block; (2) Structural heterogeneities causing an increase in λ (or CV) of >40% could result in block of premature impulses; (3) A decrease in the maximum slope of CV restitution curves of propagating premature impulses is indicative of an increased potential for block at structural heterogeneities.

  19. The Chimborazo sector collapse and debris avalanche: Deposit characteristics as evidence of emplacement mechanisms

    NASA Astrophysics Data System (ADS)

    Bernard, Benjamin; van Wyk de Vries, Benjamin; Barba, Diego; Leyrit, Hervé; Robin, Claude; Alcaraz, Samantha; Samaniego, Pablo

    2008-09-01

    Chimborazo is a Late Pleistocene to Holocene stratovolcano located at the southwest end of the main Ecuadorian volcanic arc. It experienced a large sector collapse and debris avalanche (DA) of the initial edifice (CH-I). This left a 4 km wide scar, removing 8.0 ± 0.5 km 3 of the edifice. The debris avalanche deposit (DAD) is abundantly exposed throughout the Riobamba Basin to the Río Chambo, more than 35 km southeast of the volcano. The DAD averages a thickness of 40 m, covers about 280 km 2, and has a volume of > 11 km 3. Two main DAD facies are recognized: block and mixed facies. The block facies is derived predominantly from edifice lava and forms > 80 vol.% of the DAD, with a probable volume increase of 15-25 vol.%. The mixed facies was essentially created by mixing brecciated edifice rock with substratum and is found mainly in distal and marginal areas. The DAD has clear surface ridges and hummocks, and internal structures such as jigsaw cracks, injections, and shear-zone features are widespread. Structures such as stretched blocks along the base contact indicate high basal shear. Substratum incorporation is directly observed at the base and is inferred from the presence of substratum-derived material in the DAD body. Based on the facies and structural interpretation, we propose an emplacement model of a lava-rich avalanche strongly cataclased before and/or during failure initiation. The flow mobilises and incorporates significant substrata (10-14 vol.%) while developing a fine lubricating basal layer. The substrata-dominated mixed facies is transported to the DAD interior and top in dykes invading previously-formed fractures.

  20. "Non-equilibrium" block copolymer micelles with glassy cores: a predictive approach based on theory of equilibrium micelles.

    PubMed

    Nagarajan, Ramanathan

    2015-07-01

    Micelles generated in water from most amphiphilic block copolymers are widely recognized to be non-equilibrium structures. Typically, the micelles are prepared by a kinetic process, first allowing molecular scale dissolution of the block copolymer in a common solvent that likes both the blocks and then gradually replacing the common solvent by water to promote the hydrophobic blocks to aggregate and create the micelles. The non-equilibrium nature of the micelle originates from the fact that dynamic exchange between the block copolymer molecules in the micelle and the singly dispersed block copolymer molecules in water is suppressed, because of the glassy nature of the core forming polymer block and/or its very large hydrophobicity. Although most amphiphilic block copolymers generate such non-equilibrium micelles, no theoretical approach to a priori predict the micelle characteristics currently exists. In this work, we propose a predictive approach for non-equilibrium micelles with glassy cores by applying the equilibrium theory of micelles in two steps. In the first, we calculate the properties of micelles formed in the mixed solvent while true equilibrium prevails, until the micelle core becomes glassy. In the second step, we freeze the micelle aggregation number at this glassy state and calculate the corona dimension from the equilibrium theory of micelles. The condition when the micelle core becomes glassy is independently determined from a statistical thermodynamic treatment of diluent effect on polymer glass transition temperature. The predictions based on this "non-equilibrium" model compare reasonably well with experimental data for polystyrene-polyethylene oxide diblock copolymer, which is the most extensively studied system in the literature. In contrast, the application of the equilibrium model to describe such a system significantly overpredicts the micelle core and corona dimensions and the aggregation number. The non-equilibrium model suggests ways to obtain different micelle sizes for the same block copolymer, by the choices we can make of the common solvent and the mode of solvent substitution. Published by Elsevier Inc.

  1. Tectonic geomorphology of the New Madrid seismic zone based on imaging of digital topographic data

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

    Mayer, L.

    1993-03-01

    Topographic analysis using digital elevation data of the New Madrid region focuses on topographic features that occur at several spatial scales and can be used to delineate distinct anomalies. In this region, topographic anomalies occur as domal or elongate uplifts and bowl-shaped depressions approximately 1--10 km in size, topographic lineaments, and differences in topographic blocking across 50 km long boundaries. In order to fully explain these topographic anomalies, tectonic processes may be required. Imaging is based on digital topographic data from USGS 30 arc-second, 3 arc-second, and 30 m resolutions. Imaging of these data uses standard imaging processing techniques tomore » examine topography within the contexts of geomorphological hypothesis testing. A good example is the use of thresholding to highlight areas of unusually high elevation given the hypothesis of fluvial landscape architecture. Thresholding delineates topographic features such as the Tiptonville dome which is strongly believed to be tectonic in origin. To determine the pattern of topographic blocking, defined as a pattern that topography assumes when constrained by active forces other than erosion alone, low frequency passing spatial convolutions are used as filters and the resulting data are sliced into blocks according to pseudoelevations that produce a stable block pattern. The resultant blocks are analyzed according to its structural pattern of block size and block orientation. This analysis suggests that a topographic boundary cuts across the Mississippi embayment from near the Newport pluton on the west, to the area south of Memphis on east.« less

  2. Response prediction techniques and case studies of a path blocking system based on Global Transmissibility Direct Transmissibility method

    NASA Astrophysics Data System (ADS)

    Wang, Zengwei; Zhu, Ping; Zhao, Jianxuan

    2017-02-01

    In this paper, the prediction capabilities of the Global Transmissibility Direct Transmissibility (GTDT) method are further developed. Two path blocking techniques solely using the easily measured variables of the original system to predict the response of a path blocking system are generalized to finite element models of continuous systems. The proposed techniques are derived theoretically in a general form for the scenarios of setting the response of a subsystem to zero and of removing the link between two directly connected subsystems. The objective of this paper is to verify the reliability of the proposed techniques by finite element simulations. Two typical cases, the structural vibration transmission case and the structure-borne sound case, in two different configurations are employed to illustrate the validity of proposed techniques. The points of attention for each case have been discussed, and conclusions are given. It is shown that for the two cases of blocking a subsystem the proposed techniques are able to predict the new response using measured variables of the original system, even though operational forces are unknown. For the structural vibration transmission case of removing a connector between two components, the proposed techniques are available only when the rotational component responses of the connector are very small. The proposed techniques offer relative path measures and provide an alternative way to deal with NVH problems. The work in this paper provides guidance and reference for the engineering application of the GTDT prediction techniques.

  3. Block copolymer based composition and morphology control in nanostructured hybrid materials for energy conversion and storage: solar cells, batteries, and fuel cells.

    PubMed

    Orilall, M Christopher; Wiesner, Ulrich

    2011-02-01

    The development of energy conversion and storage devices is at the forefront of research geared towards a sustainable future. However, there are numerous issues that prevent the widespread use of these technologies including cost, performance and durability. These limitations can be directly related to the materials used. In particular, the design and fabrication of nanostructured hybrid materials is expected to provide breakthroughs for the advancement of these technologies. This tutorial review will highlight block copolymers as an emerging and powerful yet affordable tool to structure-direct such nanomaterials with precise control over structural dimensions, composition and spatial arrangement of materials in composites. After providing an introduction to materials design and current limitations, the review will highlight some of the most recent examples of block copolymer structure-directed nanomaterials for photovoltaics, batteries and fuel cells. In each case insights are provided into the various underlying fundamental chemical, thermodynamic and kinetic formation principles enabling general and relatively inexpensive wet-polymer chemistry methodologies for the efficient creation of multiscale functional materials. Examples include nanostructured ceramics, ceramic-carbon composites, ceramic-carbon-metal composites and metals with morphologies ranging from hexagonally arranged cylinders to three-dimensional bi-continuous cubic networks. The review ends with an outlook towards the synthesis of multicomponent and hierarchical multifunctional hybrid materials with different nano-architectures from self-assembly of higher order blocked macromolecules which may ultimately pave the way for the further development of energy conversion and storage devices.

  4. Agar Block Smear Preparation: a Novel Method of Slide Preparation for Preservation of Native Fungal Structures for Microscopic Examination and Long-Term Storage▿

    PubMed Central

    Woo, Patrick C. Y.; Ngan, Antonio H. Y.; Chui, Hon-Kit; Lau, Susanna K. P.; Yuen, Kwok-Yung

    2010-01-01

    We describe a novel method of fungal slide preparation named “agar block smear preparation.” A total of 510 agar block smears of 25 fungal strains obtained from culture collections, 90 QC fungal strains, and 82 clinical fungal strains from our clinical microbiology laboratory, which included a total of 137 species of yeasts, molds, and thermal dimorphic fungi, were prepared and examined. In contrast to adhesive tape preparation, agar block smears preserved the native fungal structures, such as intact conidiophores of Aspergillus species and arrangements of conidia in Scopulariopsis brevicaulis. Furthermore, agar block smears allowed examination of fungal structures embedded in the agar, such as the ascomata with ascomal hairs in Chaetomium funicola; pycnidium of Phoma glomerata; the intercalary ovoidal chlamydospores arranged in chains of Fusarium dimerum; and the lateral, spherical chlamydospores arranged in pairs of Fusarium solani. After 1 year of storage, morphological integrity was found to have been maintained in 459 (90%) of the 510 agar block smears. After 3 years of storage, morphological integrity was found to have been maintained in 72 (71%) of the 102 smears prepared in 2006. Agar block smear preparation preserves the native fungal structures and allows long-term storage and examination of fungal structures embedded in the agar, hence overcoming the major drawbacks of adhesive tape preparation. The major roles of agar block smear should be diagnosis for difficult cases, accurate identification of fungal species for clinical management of patients and epidemiological studies, and long-term storage for transportation of slides and education purposes. PMID:20660221

  5. Agar block smear preparation: a novel method of slide preparation for preservation of native fungal structures for microscopic examination and long-term storage.

    PubMed

    Woo, Patrick C Y; Ngan, Antonio H Y; Chui, Hon-Kit; Lau, Susanna K P; Yuen, Kwok-Yung

    2010-09-01

    We describe a novel method of fungal slide preparation named "agar block smear preparation." A total of 510 agar block smears of 25 fungal strains obtained from culture collections, 90 QC fungal strains, and 82 clinical fungal strains from our clinical microbiology laboratory, which included a total of 137 species of yeasts, molds, and thermal dimorphic fungi, were prepared and examined. In contrast to adhesive tape preparation, agar block smears preserved the native fungal structures, such as intact conidiophores of Aspergillus species and arrangements of conidia in Scopulariopsis brevicaulis. Furthermore, agar block smears allowed examination of fungal structures embedded in the agar, such as the ascomata with ascomal hairs in Chaetomium funicola; pycnidium of Phoma glomerata; the intercalary ovoidal chlamydospores arranged in chains of Fusarium dimerum; and the lateral, spherical chlamydospores arranged in pairs of Fusarium solani. After 1 year of storage, morphological integrity was found to have been maintained in 459 (90%) of the 510 agar block smears. After 3 years of storage, morphological integrity was found to have been maintained in 72 (71%) of the 102 smears prepared in 2006. Agar block smear preparation preserves the native fungal structures and allows long-term storage and examination of fungal structures embedded in the agar, hence overcoming the major drawbacks of adhesive tape preparation. The major roles of agar block smear should be diagnosis for difficult cases, accurate identification of fungal species for clinical management of patients and epidemiological studies, and long-term storage for transportation of slides and education purposes.

  6. Structural implications of weak Ca2+ block in Drosophila cyclic nucleotide–gated channels

    PubMed Central

    Lam, Yee Ling; Zeng, Weizhong; Derebe, Mehabaw Getahun

    2015-01-01

    Calcium permeability and the concomitant calcium block of monovalent ion current (“Ca2+ block”) are properties of cyclic nucleotide–gated (CNG) channel fundamental to visual and olfactory signal transduction. Although most CNG channels bear a conserved glutamate residue crucial for Ca2+ block, the degree of block displayed by different CNG channels varies greatly. For instance, the Drosophila melanogaster CNG channel shows only weak Ca2+ block despite the presence of this glutamate. We previously constructed a series of chimeric channels in which we replaced the selectivity filter of the bacterial nonselective cation channel NaK with a set of CNG channel filter sequences and determined that the resulting NaK2CNG chimeras displayed the ion selectivity and Ca2+ block properties of the parent CNG channels. Here, we used the same strategy to determine the structural basis of the weak Ca2+ block observed in the Drosophila CNG channel. The selectivity filter of the Drosophila CNG channel is similar to that of most other CNG channels except that it has a threonine at residue 318 instead of a proline. We constructed a NaK chimera, which we called NaK2CNG-Dm, which contained the Drosophila selectivity filter sequence. The high resolution structure of NaK2CNG-Dm revealed a filter structure different from those of NaK and all other previously investigated NaK2CNG chimeric channels. Consistent with this structural difference, functional studies of the NaK2CNG-Dm chimeric channel demonstrated a loss of Ca2+ block compared with other NaK2CNG chimeras. Moreover, mutating the corresponding threonine (T318) to proline in Drosophila CNG channels increased Ca2+ block by 16 times. These results imply that a simple replacement of a threonine for a proline in Drosophila CNG channels has likely given rise to a distinct selectivity filter conformation that results in weak Ca2+ block. PMID:26283200

  7. Effects of Cationic Pendant Groups on Ionic Conductivity for Anion Exchange Membranes: Structure Conductivity Relationships

    NASA Astrophysics Data System (ADS)

    Kim, Sojeong; Choi, Soo-Hyung; Lee, Won Bo

    Anion exchange membranes(AEMs) have been widely studied due to their various applications, especially for Fuel cells. Previous proton exchange membranes(PEMs), such as Nafions® have better conductivity than AEMs so far. However, technical limitations such as slow electrode kinetics, carbon monoxide (CO) poisoning of metal catalysts, high methanol crossover and high cost of Pt-based catalyst detered further usages. AEMs have advantages to supplement its drawbacks. AEMs are environmentally friendly and cost-efficient. Based on the well-defined block copolymer, self-assembled morphology is expected to have some relationship with its ionic conductivity. Recently AEMs based on various cations, including ammonium, phosphonium, guanidinium, imidazolium, metal cation, and benzimidazolium cations have been developed and extensively studied with the aim to prepare high- performance AEMs. But more fundamental approach, such as relationships between nanostructure and conductivity is needed. We use well-defined block copolymer Poly(styrene-block-isoprene) as a backbone which is synthesized by anionic polymerization. Then we graft various cationic functional groups and analysis the relation between morphology and conductivity. Theoretical and computational soft matter lab.

  8. A Local DCT-II Feature Extraction Approach for Personal Identification Based on Palmprint

    NASA Astrophysics Data System (ADS)

    Choge, H. Kipsang; Oyama, Tadahiro; Karungaru, Stephen; Tsuge, Satoru; Fukumi, Minoru

    Biometric applications based on the palmprint have recently attracted increased attention from various researchers. In this paper, a method is presented that differs from the commonly used global statistical and structural techniques by extracting and using local features instead. The middle palm area is extracted after preprocessing for rotation, position and illumination normalization. The segmented region of interest is then divided into blocks of either 8×8 or 16×16 pixels in size. The type-II Discrete Cosine Transform (DCT) is applied to transform the blocks into DCT space. A subset of coefficients that encode the low to medium frequency components is selected using the JPEG-style zigzag scanning method. Features from each block are subsequently concatenated into a compact feature vector and used in palmprint verification experiments with palmprints from the PolyU Palmprint Database. Results indicate that this approach achieves better results than many conventional transform-based methods, with an excellent recognition accuracy above 99% and an Equal Error Rate (EER) of less than 1.2% in palmprint verification.

  9. Video error concealment using block matching and frequency selective extrapolation algorithms

    NASA Astrophysics Data System (ADS)

    P. K., Rajani; Khaparde, Arti

    2017-06-01

    Error Concealment (EC) is a technique at the decoder side to hide the transmission errors. It is done by analyzing the spatial or temporal information from available video frames. It is very important to recover distorted video because they are used for various applications such as video-telephone, video-conference, TV, DVD, internet video streaming, video games etc .Retransmission-based and resilient-based methods, are also used for error removal. But these methods add delay and redundant data. So error concealment is the best option for error hiding. In this paper, the error concealment methods such as Block Matching error concealment algorithm is compared with Frequency Selective Extrapolation algorithm. Both the works are based on concealment of manually error video frames as input. The parameter used for objective quality measurement was PSNR (Peak Signal to Noise Ratio) and SSIM(Structural Similarity Index). The original video frames along with error video frames are compared with both the Error concealment algorithms. According to simulation results, Frequency Selective Extrapolation is showing better quality measures such as 48% improved PSNR and 94% increased SSIM than Block Matching Algorithm.

  10. Fire Protection Specialist, Blocks IV and V, 17-3. Military Curriculum Materials for Vocational and Technical Education.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. National Center for Research in Vocational Education.

    This military-developed text contains the fourth and fifth blocks of a five-block course for use in training fire protection specialists. Covered in the individual volumes are the following topics: structural firefighting (operation and maintenance of hydrants, emergency response activities, structural pumpers, vehicle positioning and relay, hose…

  11. Sandblasting may damage the surface of composite CAD-CAM blocks.

    PubMed

    Yoshihara, Kumiko; Nagaoka, Noriyuki; Maruo, Yukinori; Nishigawa, Goro; Irie, Masao; Yoshida, Yasuhiro; Van Meerbeek, Bart

    2017-03-01

    CAD-CAM blocks to fabricate semi-direct and indirect restorations are available in different sorts of ceramics as well as composite. In order to bond restorations prepared out of composite blocks into tooth cavities, it is recommended to gently sandblast the surface prior to the application of a primer/adhesive. Today, the effect of sandblasting composite block surfaces has not thoroughly been investigated. In this study, the ultra-structure of composite CAD-CAM blocks was investigated with special attention to the effect of sandblasting on the surface topography and of silanization on the bonding performance. Five different composite CAD-CAM blocks were involved. We correlatively investigated their structural and chemical composition using X-ray diffraction (XRD), energy dispersion spectroscopy (EDS), scanning electron microscopy (SEM) and (scanning) transmission electron microscopy ((S)TEM). The effect of sandblasting was also imaged in cross-section and at the interface with composite cement. Finally, we measured the shear bond strength to the sandblasted block surface with and without silanization. All composite blocks revealed a different ultra-structure. Sandblasting increased surface roughness and resulted in an irregular surface with some filler exposure. Sandblasting also damaged the surface. When the sandblasted composite blocks were silanized, superior bonding receptiveness in terms of higher bond strength was achieved except for Shofu Block HC. Sandblasting followed by silanization improved the bond strength to composite CAD-CAM blocks. However, sandblasting may also damage the composite CAD-CAM block surface. For the composite CAD-CAM block Shofu Block HC, the damage was so severe that silanization did not improve bond strength. Copyright © 2016 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  12. Endocytotic uptake of HPMA-based polymers by different cancer cells: impact of extracellular acidosis and hypoxia

    PubMed Central

    Gündel, Daniel; Allmeroth, Mareli; Reime, Sarah; Zentel, Rudolf; Thews, Oliver

    2017-01-01

    Background Polymeric nanoparticles allow to selectively transport chemotherapeutic drugs to the tumor tissue. These nanocarriers have to be taken up into the cells to release the drug. In addition, tumors often show pathological metabolic characteristics (hypoxia and acidosis) which might affect the polymer endocytosis. Materials and methods Six different N-(2-hydroxypropyl)methacrylamide (HPMA)-based polymer structures (homopolymer as well as random and block copolymers with lauryl methacrylate containing hydrophobic side chains) varying in molecular weight and size were analyzed in two different tumor models. The cellular uptake of fluorescence-labeled polymers was measured under hypoxic (pO2 ≈1.5 mmHg) and acidic (pH 6.6) conditions. By using specific inhibitors, different endocytotic routes (macropinocytosis and clathrin-mediated, dynamin-dependent, cholesterol-dependent endocytosis) were analyzed separately. Results The current results revealed that the polymer uptake depends on the molecular structure, molecular weight and tumor line used. In AT1 cells, the uptake of random copolymer was five times stronger than the homopolymer, whereas in Walker-256 cells, the uptake of all polymers was much stronger, but this was independent of the molecular structure and size. Acidosis increased the uptake of random copolymer in AT1 cells but reduced the intracellular accumulation of homopolymer and block copolymer. Hypoxia reduced the uptake of all polymers in Walker-256 cells. Hydrophilic polymers (homopolymer and block copolymer) were taken up by all endocytotic routes studied, whereas the more lipophilic random copolymer seemed to be taken up preferentially by cholesterol- and dynamin-dependent endocytosis. Conclusion The study indicates that numerous parameters of the polymer (structure, size) and of the tumor (perfusion, vascular permeability, pH, pO2) modulate drug delivery, which makes it difficult to select the appropriate polymer for the individual patient. PMID:28831253

  13. Endocytotic uptake of HPMA-based polymers by different cancer cells: impact of extracellular acidosis and hypoxia.

    PubMed

    Gündel, Daniel; Allmeroth, Mareli; Reime, Sarah; Zentel, Rudolf; Thews, Oliver

    2017-01-01

    Polymeric nanoparticles allow to selectively transport chemotherapeutic drugs to the tumor tissue. These nanocarriers have to be taken up into the cells to release the drug. In addition, tumors often show pathological metabolic characteristics (hypoxia and acidosis) which might affect the polymer endocytosis. Six different N -(2-hydroxypropyl)methacrylamide (HPMA)-based polymer structures (homopolymer as well as random and block copolymers with lauryl methacrylate containing hydrophobic side chains) varying in molecular weight and size were analyzed in two different tumor models. The cellular uptake of fluorescence-labeled polymers was measured under hypoxic (pO 2 ≈1.5 mmHg) and acidic (pH 6.6) conditions. By using specific inhibitors, different endocytotic routes (macropinocytosis and clathrin-mediated, dynamin-dependent, cholesterol-dependent endocytosis) were analyzed separately. The current results revealed that the polymer uptake depends on the molecular structure, molecular weight and tumor line used. In AT1 cells, the uptake of random copolymer was five times stronger than the homopolymer, whereas in Walker-256 cells, the uptake of all polymers was much stronger, but this was independent of the molecular structure and size. Acidosis increased the uptake of random copolymer in AT1 cells but reduced the intracellular accumulation of homopolymer and block copolymer. Hypoxia reduced the uptake of all polymers in Walker-256 cells. Hydrophilic polymers (homopolymer and block copolymer) were taken up by all endocytotic routes studied, whereas the more lipophilic random copolymer seemed to be taken up preferentially by cholesterol- and dynamin-dependent endocytosis. The study indicates that numerous parameters of the polymer (structure, size) and of the tumor (perfusion, vascular permeability, pH, pO 2 ) modulate drug delivery, which makes it difficult to select the appropriate polymer for the individual patient.

  14. Identifying Effective Design Approaches to Allocate Genotypes in Two-Phase Designs: A Case Study in Pelargonium zonale.

    PubMed

    Molenaar, Heike; Boehm, Robert; Piepho, Hans-Peter

    2017-01-01

    Robust phenotypic data allow adequate statistical analysis and are crucial for any breeding purpose. Such data is obtained from experiments laid out to best control local variation. Additionally, experiments frequently involve two phases, each contributing environmental sources of variation. For example, in a former experiment we conducted to evaluate production related traits in Pelargonium zonale , there were two consecutive phases, each performed in a different greenhouse. Phase one involved the propagation of the breeding strains to obtain the stem cutting count, and phase two involved the assessment of root formation. The evaluation of the former study raised questions regarding options for improving the experimental layout: (i) Is there a disadvantage to using exactly the same design in both phases? (ii) Instead of generating a separate layout for each phase, can the design be optimized across both phases, such that the mean variance of a pair-wise treatment difference (MVD) can be decreased? To answer these questions, alternative approaches were explored to generate two-phase designs either in phase-wise order (Option 1) or across phases (Option 2). In Option 1 we considered the scenarios (i) using in both phases the same experimental design and (ii) randomizing each phase separately. In Option 2, we considered the scenarios (iii) generating a single design with eight replicates and splitting these among the two phases, (iv) separating the block structure across phases by dummy coding, and (v) design generation with optimal alignment of block units in the two phases. In both options, we considered the same or different block structures in each phase. The designs were evaluated by the MVD obtained by the intra-block analysis and the joint inter-block-intra-block analysis. The smallest MVD was most frequently obtained for designs generated across phases rather than for each phase separately, in particular when both phases of the design were separated with a single pseudo-level. The joint optimization ensured that treatment concurrences were equally balanced across pairs, one of the prerequisites for an efficient design. The proposed alternative approaches can be implemented with any model-based design packages with facilities to formulate linear models for treatment and block structures.

  15. Synthesis and Characterization of Stimuli Responsive Block Copolymers, Self-Assembly Behavior and Applications

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

    Determan, Michael Duane

    The central theme of this thesis work is to develop new block copolymer materials for biomedical applications. While there are many reports of stimuli-responsive amphiphilic [19-21] and crosslinked hydrogel materials [22], the development of an in situ gel forming, pH responsive pentablock copolymer is a novel contribution to the field, Figure 1.1 is a sketch of an ABCBA pentablock copolymer. The A blocks are cationic tertiary amine methacrylates blocked to a central Pluronic F127 triblock copolymer. In addition to the prerequisite synthetic and macromolecular characterization of these new materials, the self-assembled supramolecular structures formed by the pentablock were experimentally evaluated.more » This synthesis and characterization process serves to elucidate the important structure property relationships of these novel materials, The pH and temperature responsive behavior of the pentablock copolymer were explored especially with consideration towards injectable drug delivery applications. Future synthesis work will focus on enhancing and tuning the cell specific targeting of DNA/pentablock copolymer polyplexes. The specific goals of this research are: (1) Develop a synthetic route for gel forming pentablock block copolymers with pH and temperature sensitive properties. Synthesis of these novel copolymers is accomplished with ATRP, yielding low polydispersity and control of the block copolymer architecture. Well defined macromolecular characteristics are required to tailor the phase behavior of these materials. (2) Characterize relationship between the size and shape of pentablock copolymer micelles and gel structure and the pH and temperature of the copolymer solutions with SAXS, SANS and CryoTEM. (3) Evaluate the temperature and pH induced phase separation and macroscopic self-assembly phenomenon of the pentablock copolymer. (4) Utilize the knowledge gained from first three goals to design and formulate drug delivery formulations based on the multi-responsive properties of the pentablock copolymer. Demonstrate potential biomedical applications of these materials with in vitro drug release studies from pentablock copolymer hydrogels. The intent of this work is to contribute to the knowledge necessary for further tailoring of these, and other functional block copolymer materials for biomedical applications.« less

  16. Genetics Home Reference: combined malonic and methylmalonic aciduria

    MedlinePlus

    ... acids are building blocks used to make fats (lipids). The ACSF3 enzyme performs a chemical reaction that converts malonic acid to malonyl-CoA, which is the first step of fatty acid synthesis in cellular structures called mitochondria . Based on this activity, the enzyme ...

  17. Papers in Syntax. Working Papers in Linguistics No. 42.

    ERIC Educational Resources Information Center

    Kathol, Andreas, Ed.; Pollard, Carl, Ed.

    1993-01-01

    This collection of working papers in syntax includes: "Null Objects in Mandarin Chinese" (Christie Block); "Toward a Linearization-Based Approach to Word Order Variation in Japanese" (Mike Calcagno); "A Lexical Approach to Inalienable Possession Constructions in Korean" (Chung, Chan); "Chinese NP Structure"…

  18. Comparison of Measured and Block Structured Simulations for the F-16XL Aircraft

    NASA Technical Reports Server (NTRS)

    Boelens, O. J.; Badcock, K. J.; Elmilgui, A.; Abdol-Hamid, K. S.; Massey, S. J.

    2008-01-01

    This article presents a comparison of the predictions of three RANS codes for flight conditions of the F-16XL aircraft which feature vortical flow. The three codes, ENSOLV, PMB and PAB3D, solve on structured multi-block grids. Flight data for comparison was available in the form of surface pressures, skin friction, boundary layer data and photographs of tufts. The three codes provided predictions which were consistent with expectations based on the turbulence modelling used, which was k- , k- with vortex corrections and an Algebraic Stress Model. The agreement with flight data was good, with the exception of the outer wing primary vortex strength. The confidence in the application of the CFD codes to complex fighter configurations increased significantly through this study.

  19. Evolutionary Construction of Block-Based Neural Networks in Consideration of Failure

    NASA Astrophysics Data System (ADS)

    Takamori, Masahito; Koakutsu, Seiichi; Hamagami, Tomoki; Hirata, Hironori

    In this paper we propose a modified gene coding and an evolutionary construction in consideration of failure in evolutionary construction of Block-Based Neural Networks. In the modified gene coding, we arrange the genes of weights on a chromosome in consideration of the position relation of the genes of weight and structure. By the modified gene coding, the efficiency of search by crossover is increased. Thereby, it is thought that improvement of the convergence rate of construction and shortening of construction time can be performed. In the evolutionary construction in consideration of failure, the structure which is adapted for failure is built in the state where failure occured. Thereby, it is thought that BBNN can be reconstructed in a short time at the time of failure. To evaluate the proposed method, we apply it to pattern classification and autonomous mobile robot control problems. The computational experiments indicate that the proposed method can improve convergence rate of construction and shorten of construction and reconstruction time.

  20. Rapid shear alignment of sub-10 nm cylinder-forming block copolymer films based on thermal expansion mismatch

    NASA Astrophysics Data System (ADS)

    Nicaise, Samuel M.; Gadelrab, Karim R.; G, Amir Tavakkoli K.; Ross, Caroline A.; Alexander-Katz, Alfredo; Berggren, Karl K.

    2018-01-01

    Directed self-assembly of block copolymers (BCPs) provided by shear-stress can produce aligned sub-10 nm structures over large areas for applications in integrated circuits, next-generation data storage, and plasmonic structures. In this work, we present a fast, versatile BCP shear-alignment process based on coefficient of thermal expansion mismatch of the BCP film, a rigid top coat and a substrate. Monolayer and bilayer cylindrical microdomains of poly(styrene-b-dimethylsiloxane) aligned preferentially in-plane and orthogonal to naturally-forming or engineered cracks in the top coat film, allowing for orientation control over 1 cm2 substrates. Annealing temperatures, up to 275 °C, provided low-defect alignment up to 2 mm away from cracks for rapid (<1 min) annealing times. Finite-element simulations of the stress as a function of annealing time, annealing temperature, and distance from cracks showed that shear stress during the cooling phase of the thermal annealing was critical for the observed microdomain alignment.

  1. Synthesis and wound healing of alternating block polyurethanes based on poly(lactic acid) (PLA) and poly(ethylene glycol) (PEG).

    PubMed

    Li, Linjing; Liu, Xiangyu; Niu, Yuqing; Ye, Jianfu; Huang, Shuiwen; Liu, Chao; Xu, Kaitian

    2017-07-01

    Alternating block polyurethanes (abbreviated as PULA-alt-PEG) and random block polyurethanes (abbreviated as PULA-ran-PEG) based on biodegradable poly(lactic acid) (PLA) and poly(ethylene glycol) (PEG) were prepared. Results showed that alternating block polyurethane gives higher crystal degree, higher mechanical properties, more patterned and rougher surface than the random counterpart, due to the regular and controlled structure. Water absorptions of the polyurethanes were in the range of 620 to 780%. Cytocompatibility of the amphiphilic block polyurethanes (PU) (water static angle 41.4°-61.8°) was assessed by CCK-8 assay using human embryonic kidney (HEK293) cells. Wound healing evaluation of the PU foam scaffolds was carried out by full-thickness SD rat model experiment, with medical gauze as control. It was found that the skin of rat in PU groups was fully covered with new epithelium without any significant adverse reactions and PU dressings give much rapid and better healing than medical gauze. Histological examination revealed that PU dressings suppress the infiltration of inflammatory cells and accelerate fibroblast proliferation. It was also demonstrated that PULA-alt-PEG exhibits obvious better healing effect than PULA-ran-PEG does. This study has demonstrated that without further modification, plain alternating block polyurethane scaffold would help wound recovery efficiently. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1200-1209, 2017. © 2016 Wiley Periodicals, Inc.

  2. Extrapunitive and intropunitive individuals activate different parts of the prefrontal cortex under an ego-blocking frustration.

    PubMed

    Minamoto, Takehiro; Osaka, Mariko; Yaoi, Ken; Osaka, Naoyuki

    2014-01-01

    Different people make different responses when they face a frustrating situation: some punish others (extrapunitive), while others punish themselves (intropunitive). Few studies have investigated the neural structures that differentiate extrapunitive and intropunitive individuals. The present fMRI study explored these neural structures using two different frustrating situations: an ego-blocking situation which blocks a desire or goal, and a superego-blocking situation which blocks self-esteem. In the ego-blocking condition, the extrapunitive group (n = 9) showed greater activation in the bilateral ventrolateral prefrontal cortex, indicating that these individuals prefer emotional processing. On the other hand, the intropunitive group (n = 9) showed greater activation in the left dorsolateral prefrontal cortex, possibly reflecting an effortful control for anger reduction. Such patterns were not observed in the superego-blocking condition. These results indicate that the prefrontal cortex is the source of individual differences in aggression direction in the ego-blocking situation.

  3. The development of poly(vinyl chloride) [PVC] extrusions for a 14,000-ton self-supporting structure for the detection of neutrinos

    DOE PAGES

    Grudzinski, James J.; Talaga, Richard L.; Pla-Dalmau, Anna; ...

    2014-12-16

    The NOvA Neutrino Experiment has built a one of a kind self-supporting plastic structure, potentially the largest ever built. The PVC structure serves as a neutrino detector and is composed of 28 individual blocks that measure 15.5 m (51 feet) high by 15.5 m (51 feet) wide by 2.1 m (7 feet) deep. The primary parts in the detector construction are 15.5m (51 foot), 15-cell PVC extrusions. These extrusions from the basis of the detector modules which are laminated together in a crossed pattern to form the individual blocks and then filled with mineral oil based liquid scintillator. The self-supportingmore » nature of the detector places important structural requirements on both the PVC formulation and the extrusions. Block assembly requirements impose narrow geometric tolerances. Due to the method of detecting neutrinos, the extrusions must possess exceptionally high reflectivity over a particular wavelength range. The requirement places additional restrictions on the components of the PVC formulation. Altogether, the PVC extrusions have to maintain important reflectivity characteristics, provide structural support to the detector, and meet relatively tight geometric requirements for assembly. In order to meet these constraints, a custom PVC formulation had to be created and extruded. Here, we describe the purpose and requirements of the NOvA detector leading to the production of our unique PVC extrusion, summarize the R&D process, and discuss the lessons learned.« less

  4. A three-sided rearrangeable switching network for a binary fat tree

    NASA Astrophysics Data System (ADS)

    Yen, Mao-Hsu; Yu, Chu; Shin, Haw-Yun; Chen, Sao-Jie

    2011-06-01

    A binary fat tree needs an internal node to interconnect the left-children, right-children and parent terminals to each other. In this article, we first propose a three-stage, 3-sided rearrangeable switching network for the implementation of a binary fat tree. The main component of this 3-sided switching network (3SSN) consists of a polygonal switch block (PSB) interconnected by crossbars. With the same size and the same number of switches as our 3SSN, a three-stage, 3-sided clique-based switching network is shown to be not rearrangeable. Also, the effects of the rearrangeable structure and the number of terminals on the network switch-efficiency are explored and a proper set of parameters has been determined to minimise the number of switches. We derive that a rearrangeable 3-sided switching network with switches proportional to N 3/2 is most suitable to interconnect N terminals. Moreover, we propose a new Polygonal Field Programmable Gate Array (PFPGA) that consists of logic blocks interconnected by our 3SSN, such that the logic blocks in this PFPGA can be grouped into clusters to implement different logic functions. Since the programmable switches usually have high resistance and capacitance and occupy a large area, we have to consider the effect of the 3SSN structure and the granularity of its cluster logic blocks on the switch efficiency of PFPGA. Experiments on benchmark circuits show that the switch and speed performances are significantly improved. Based on the experimental results, we can determine the parameters of PFPGA for the VLSI implementation.

  5. Design and simulation of programmable relational optoelectronic time-pulse coded processors as base elements for sorting neural networks

    NASA Astrophysics Data System (ADS)

    Krasilenko, Vladimir G.; Nikolsky, Alexander I.; Lazarev, Alexander A.; Lazareva, Maria V.

    2010-05-01

    In the paper we show that the biologically motivated conception of time-pulse encoding usage gives a set of advantages (single methodological basis, universality, tuning simplicity, learning and programming et al) at creation and design of sensor systems with parallel input-output and processing for 2D structures hybrid and next generations neuro-fuzzy neurocomputers. We show design principles of programmable relational optoelectronic time-pulse encoded processors on the base of continuous logic, order logic and temporal waves processes. We consider a structure that execute analog signal extraction, analog and time-pulse coded variables sorting. We offer optoelectronic realization of such base relational order logic element, that consists of time-pulse coded photoconverters (pulse-width and pulse-phase modulators) with direct and complementary outputs, sorting network on logical elements and programmable commutation blocks. We make technical parameters estimations of devices and processors on such base elements by simulation and experimental research: optical input signals power 0.2 - 20 uW, processing time 1 - 10 us, supply voltage 1 - 3 V, consumption power 10 - 100 uW, extended functional possibilities, learning possibilities. We discuss some aspects of possible rules and principles of learning and programmable tuning on required function, relational operation and realization of hardware blocks for modifications of such processors. We show that it is possible to create sorting machines, neural networks and hybrid data-processing systems with untraditional numerical systems and pictures operands on the basis of such quasiuniversal hardware simple blocks with flexible programmable tuning.

  6. Structure of bicomponent particles synthesized from colliding metal clusters

    NASA Astrophysics Data System (ADS)

    Kryzhevich, D. S.; Zolnikov, K. P.; Korchuganov, A. V.; Psakhie, S. G.

    2017-12-01

    Here, based on a molecular dynamics simulation with many-body interaction potentials, we consider several scenarios of the formation of bicomponent particles from colliding clusters in an electrical explosion of Cu and Ni wires. The data suggest that the structure of bicomponent particles depends largely on the explosion time of one wire with respect to the other and on the phase state of colliding clusters. Diagrams are presented demonstrating the dynamics of bicomponent particles with block structure synthesized from crystalline Ni and molten Cu clusters.

  7. Seismic Evidence for a Geosuture between the Yangtze and Cathaysia Blocks, South China

    PubMed Central

    He, Chuansong; Dong, Shuwen; Santosh, M.; Chen, Xuanhua

    2013-01-01

    South China, composed of the Yangtze and Cathaysia Blocks and the intervening Jiangnan orogenic belt, has been central to the debate on the tectonic evolution of East Asia. Here we investigate the crustal structure and composition of South China from seismic data employing the H-k stacking technique. Our results show that the composition and seismic structure of the crust in the Jiangnan orogenic belt are identical to those of the Cathaysia Block. Our data reveal a distinct contrast in the crustal structure and composition between the two flanks of the Jiujiang-Shitai buried fault. We propose that the Jiujiang-Shitai buried fault defines a geosuture between the Yangtze and Cathaysia Blocks, and that the felsic lower crust of the Cathaysia Block and the Jiangnan orogenic belt may represent fragments derived from the Gondwana supercontinent. PMID:23857499

  8. Protograph based LDPC codes with minimum distance linearly growing with block size

    NASA Technical Reports Server (NTRS)

    Divsalar, Dariush; Jones, Christopher; Dolinar, Sam; Thorpe, Jeremy

    2005-01-01

    We propose several LDPC code constructions that simultaneously achieve good threshold and error floor performance. Minimum distance is shown to grow linearly with block size (similar to regular codes of variable degree at least 3) by considering ensemble average weight enumerators. Our constructions are based on projected graph, or protograph, structures that support high-speed decoder implementations. As with irregular ensembles, our constructions are sensitive to the proportion of degree-2 variable nodes. A code with too few such nodes tends to have an iterative decoding threshold that is far from the capacity threshold. A code with too many such nodes tends to not exhibit a minimum distance that grows linearly in block length. In this paper we also show that precoding can be used to lower the threshold of regular LDPC codes. The decoding thresholds of the proposed codes, which have linearly increasing minimum distance in block size, outperform that of regular LDPC codes. Furthermore, a family of low to high rate codes, with thresholds that adhere closely to their respective channel capacity thresholds, is presented. Simulation results for a few example codes show that the proposed codes have low error floors as well as good threshold SNFt performance.

  9. Analysis of conserved noncoding DNA in Drosophila reveals similar constraints in intergenic and intronic sequences.

    PubMed

    Bergman, C M; Kreitman, M

    2001-08-01

    Comparative genomic approaches to gene and cis-regulatory prediction are based on the principle that differential DNA sequence conservation reflects variation in functional constraint. Using this principle, we analyze noncoding sequence conservation in Drosophila for 40 loci with known or suspected cis-regulatory function encompassing >100 kb of DNA. We estimate the fraction of noncoding DNA conserved in both intergenic and intronic regions and describe the length distribution of ungapped conserved noncoding blocks. On average, 22%-26% of noncoding sequences surveyed are conserved in Drosophila, with median block length approximately 19 bp. We show that point substitution in conserved noncoding blocks exhibits transition bias as well as lineage effects in base composition, and occurs more than an order of magnitude more frequently than insertion/deletion (indel) substitution. Overall, patterns of noncoding DNA structure and evolution differ remarkably little between intergenic and intronic conserved blocks, suggesting that the effects of transcription per se contribute minimally to the constraints operating on these sequences. The results of this study have implications for the development of alignment and prediction algorithms specific to noncoding DNA, as well as for models of cis-regulatory DNA sequence evolution.

  10. Investigation of Kevlar fabric-based materials for use with inflatable structures

    NASA Technical Reports Server (NTRS)

    Niccum, R. J.; Munson, J. B.; Rueter, L. L.

    1977-01-01

    Design, manufacture and testing of laminated and coated composite materials incorporating a structural matrix of Kevlar are reported. The practicality of using Kevlar in aerostat materials is demonstrated, and data are provided on practical weaves, lamination and coating particulars, rigidity, strength, weight, elastic coefficients, abrasion resistance, crease effects, peel strength, blocking tendencies, helium permeability, and fabrication techniques. Properties of the Kevlar-based materials are compared with conventional Dacron-reinforced counterparts. A comprehensive test and qualification program is discussed, and considerable quantitative biaxial tensile and shear test data are provided.

  11. Molecular recognition in poly(epsilon-caprolactone)-based thermoplastic elastomers.

    PubMed

    Wisse, Eva; Spiering, A J H; van Leeuwen, Ellen N M; Renken, Raymond A E; Dankers, Patricia Y W; Brouwer, Linda A; van Luyn, Marja J A; Harmsen, Martin C; Sommerdijk, Nico A J M; Meijer, E W

    2006-12-01

    The molecular recognition properties of the hydrogen bonding segments in biodegradable thermoplastic elastomers were explored, aiming at the further functionalization of these potentially interesting biomaterials. A poly(epsilon-caprolactone)-based poly(urea) 2 was synthesized and characterized in terms of mechanical properties, processibility and histocompatibility. Comparison of the data with those obtained from the structurally related poly(urethane urea) 1 revealed that the difference in hard segment structure does not significantly affect the potency for application as a biomaterial. Nevertheless, the small differences in hard block composition had a strong effect on the molecular recognition properties of the hydrogen bonding segments. High selectivity was found for poly(urea) 2 in which bisureidobutylene-functionalized azobenzene dye 3 was selectively incorporated while bisureidopentylene-functionalized azobenzene dye 4 was completely released. In contrast, the incorporation of both dyes in poly(urethane urea) 1 led in both cases to their gradual release in time. Thermal analysis of the polymers in combination with variable temperature infrared experiments indicated that the hard blocks in 1 showed a sharp melting point, whereas those in 2 showed a very broad melting trajectory. This suggests a more precise organization of the hydrogen bonding segments in the hard blocks of poly(urea) 2 compared to poly(urethane urea) 1 and explains the results from the molecular recognition experiments. Preliminary results revealed that a bisureidobutylene-functionalized GRGDS peptide showed more supramolecular interaction with the PCL-based poly(urea), containing the bisureidobutylene recognition unit, as compared to HMW PCL, lacking this recognition unit.

  12. Micellar Self-Assembly of Recombinant Resilin-/Elastin-Like Block Copolypeptides.

    PubMed

    Weitzhandler, Isaac; Dzuricky, Michael; Hoffmann, Ingo; Garcia Quiroz, Felipe; Gradzielski, Michael; Chilkoti, Ashutosh

    2017-08-14

    Reported here is the synthesis of perfectly sequence defined, monodisperse diblock copolypeptides of hydrophilic elastin-like and hydrophobic resilin-like polypeptide blocks and characterization of their self-assembly as a function of structural parameters by light scattering, cryo-TEM, and small-angle neutron scattering. A subset of these diblock copolypeptides exhibit lower critical solution temperature and upper critical solution temperature phase behavior and self-assemble into spherical or cylindrical micelles. Their morphologies are dictated by their chain length, degree of hydrophilicity, and hydrophilic weight fraction of the ELP block. We find that (1) independent of the length of the corona-forming ELP block there is a minimum threshold in the length of the RLP block below which self-assembly does not occur, but that once that threshold is crossed, (2) the RLP block length is a unique molecular parameter to independently tune self-assembly and (3) increasing the hydrophobicity of the corona-forming ELP drives a transition from spherical to cylindrical morphology. Unlike the self-assembly of purely ELP-based block copolymers, the self-assembly of RLP-ELPs can be understood by simple principles of polymer physics relating hydrophilic weight fraction and polymer-polymer and polymer-solvent interactions to micellar morphology, which is important as it provides a route for the de novo design of desired nanoscale morphologies from first principles.

  13. Entropic fluctuations in DNA sequences

    NASA Astrophysics Data System (ADS)

    Thanos, Dimitrios; Li, Wentian; Provata, Astero

    2018-03-01

    The Local Shannon Entropy (LSE) in blocks is used as a complexity measure to study the information fluctuations along DNA sequences. The LSE of a DNA block maps the local base arrangement information to a single numerical value. It is shown that despite this reduction of information, LSE allows to extract meaningful information related to the detection of repetitive sequences in whole chromosomes and is useful in finding evolutionary differences between organisms. More specifically, large regions of tandem repeats, such as centromeres, can be detected based on their low LSE fluctuations along the chromosome. Furthermore, an empirical investigation of the appropriate block sizes is provided and the relationship of LSE properties with the structure of the underlying repetitive units is revealed by using both computational and mathematical methods. Sequence similarity between the genomic DNA of closely related species also leads to similar LSE values at the orthologous regions. As an application, the LSE covariance function is used to measure the evolutionary distance between several primate genomes.

  14. Synthesis, structure and luminescence of novel co-crystals based on bispyridyl-substituted α,β-unsaturated ketones with coformers

    NASA Astrophysics Data System (ADS)

    Li, Hong-Juan; Wang, Lei; Zhao, Juan-Juan; Sun, Ju-Feng; Sun, Ji-Liang; Wang, Chun-Hua; Hou, Gui-Ge

    2015-01-01

    Based on 2,6-bis((pyridin-4-yl)methylene)cyclohexanone (A) and N-methyl-3,5-bis((pyridin-4-yl)methylene)-4-piperidone (B) with coformers, three novel macrocyclic co-crystals, (A)ṡ(resorcinol) (1), (A)ṡ(1,3,5-benzenetriol) (2), (B)2ṡ(1,3,5-benzenetriol)2 (3) and three chain co-crystals, (A)ṡ(hydroquinone) (4), (A)ṡ(isophthalic acid) (5), (B)ṡ(isophthalic acid) (6) have been synthesized and structurally characterized by IR, 1H NMR and X-ray crystal structure analysis. Structural analysis indicates that four-component macrocycles in 1-3 are generated from "clip-like" resorcinol templates and building blocks, while 4-6 show infinite H-bonding chains. In addition, the luminescent properties of A, B and 1-6 are investigated primarily in the solid state. Compared with free building blocks, 1-6 are blue-shifted 55-60 nm with decreasing emission intensities in spite of the enhancement in 6. The change of luminescent properties might be caused mainly by incorporation of coformers into co-crystals, including H-bonds, molecular conformations, arranging dispositions and π-π characteristics. It might have potential applications for crystal engineering to construct patentable crystals with interesting luminescent properties.

  15. Structural Color for Additive Manufacturing: 3D-Printed Photonic Crystals from Block Copolymers.

    PubMed

    Boyle, Bret M; French, Tracy A; Pearson, Ryan M; McCarthy, Blaine G; Miyake, Garret M

    2017-03-28

    The incorporation of structural color into 3D printed parts is reported, presenting an alternative to the need for pigments or dyes for colored parts produced through additive manufacturing. Thermoplastic build materials composed of dendritic block copolymers were designed, synthesized, and used to additively manufacture plastic parts exhibiting structural color. The reflection properties of the photonic crystals arise from the periodic nanostructure formed through block copolymer self-assembly during polymer processing. The wavelength of reflected light could be tuned across the visible spectrum by synthetically controlling the block copolymer molecular weight and manufacture parts that reflected violet, green, or orange light with the capacity to serve as selective optical filters and light guides.

  16. Highχ block copolymers for directed self-assembly patterning without the need for topcoat or solvent annealing

    NASA Astrophysics Data System (ADS)

    Xu, Kui; Hockey, Mary Ann; Calderas, Eric; Guerrero, Douglas; Sweat, Daniel; Fiehler, Jeffrey

    2017-03-01

    High-χ block copolymers for directed self-assembly (DSA) patterning that do not need topcoat or solvent annealing have been developed. A variety of functionalities have been successfully added into the block copolymers, such as balanced surface energy between the polymer blocks, outstandingly high χ, tunable glass transition temperature (Tg), and selective crosslinking. Perpendicular orientation control, as desired for patterning, of the block copolymers can be simply achieved by thermal annealing due to the equal surface energy of the polymer blocks at the annealing temperatures, which allows avoiding solvent annealing or top-coat. The χ value can be tuned up to achieve L0 as low as 8-10 nm for lamellar-structured block copolymers and hole/pillar size as small as 5-6 nm for cylinder-structured block copolymers. The Tg of the block copolymers can be tuned to improve the kinetics of thermal annealing by enhancing the polymer chain mobility. Block-selective crosslinking facilitates the pattern transfer by mitigating pattern collapse during wet etching and improving oxygen plasma etching selectivity between the polymer blocks. This paper provides an introductory review of our high-χ block copolymer materials with various functionalities for achieving improved DSA performance.

  17. A structure preserving Lanczos algorithm for computing the optical absorption spectrum

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

    Shao, Meiyue; Jornada, Felipe H. da; Lin, Lin

    2016-11-16

    We present a new structure preserving Lanczos algorithm for approximating the optical absorption spectrum in the context of solving full Bethe-Salpeter equation without Tamm-Dancoff approximation. The new algorithm is based on a structure preserving Lanczos procedure, which exploits the special block structure of Bethe-Salpeter Hamiltonian matrices. A recently developed technique of generalized averaged Gauss quadrature is incorporated to accelerate the convergence. We also establish the connection between our structure preserving Lanczos procedure with several existing Lanczos procedures developed in different contexts. Numerical examples are presented to demonstrate the effectiveness of our Lanczos algorithm.

  18. a Voxel-Based Filtering Algorithm for Mobile LIDAR Data

    NASA Astrophysics Data System (ADS)

    Qin, H.; Guan, G.; Yu, Y.; Zhong, L.

    2018-04-01

    This paper presents a stepwise voxel-based filtering algorithm for mobile LiDAR data. In the first step, to improve computational efficiency, mobile LiDAR points, in xy-plane, are first partitioned into a set of two-dimensional (2-D) blocks with a given block size, in each of which all laser points are further organized into an octree partition structure with a set of three-dimensional (3-D) voxels. Then, a voxel-based upward growing processing is performed to roughly separate terrain from non-terrain points with global and local terrain thresholds. In the second step, the extracted terrain points are refined by computing voxel curvatures. This voxel-based filtering algorithm is comprehensively discussed in the analyses of parameter sensitivity and overall performance. An experimental study performed on multiple point cloud samples, collected by different commercial mobile LiDAR systems, showed that the proposed algorithm provides a promising solution to terrain point extraction from mobile point clouds.

  19. Macroscale and Nanoscale Morphology Evolution during in Situ Spray Coating of Titania Films for Perovskite Solar Cells.

    PubMed

    Su, Bo; Caller-Guzman, Herbert A; Körstgens, Volker; Rui, Yichuan; Yao, Yuan; Saxena, Nitin; Santoro, Gonzalo; Roth, Stephan V; Müller-Buschbaum, Peter

    2017-12-20

    Mesoporous titania is a cheap and widely used material for photovoltaic applications. To enable a large-scale fabrication and a controllable pore size, we combined a block copolymer-assisted sol-gel route with spray coating to fabricate titania films, in which the block copolymer polystyrene-block-poly(ethylene oxide) (PS-b-PEO) is used as a structure-directing template. Both the macroscale and nanoscale are studied. The kinetics and thermodynamics of the spray deposition processes are simulated on a macroscale, which shows a good agreement with the large-scale morphology of the spray-coated films obtained in practice. On the nanoscale, the structure evolution of the titania films is probed with in situ grazing incidence small-angle X-ray scattering (GISAXS) during the spray process. The changes of the PS domain size depend not only on micellization but also on solvent evaporation during the spray coating. Perovskite (CH 3 NH 3 PbI 3 ) solar cells (PSCs) based on sprayed titania film are fabricated, which showcases the suitability of spray-deposited titania films for PSCs.

  20. Parallel Adjective High-Order CFD Simulations Characterizing SOFIA Cavity Acoustics

    NASA Technical Reports Server (NTRS)

    Barad, Michael F.; Brehm, Christoph; Kiris, Cetin C.; Biswas, Rupak

    2016-01-01

    This paper presents large-scale MPI-parallel computational uid dynamics simulations for the Stratospheric Observatory for Infrared Astronomy (SOFIA). SOFIA is an airborne, 2.5-meter infrared telescope mounted in an open cavity in the aft fuselage of a Boeing 747SP. These simulations focus on how the unsteady ow eld inside and over the cavity interferes with the optical path and mounting structure of the telescope. A temporally fourth-order accurate Runge-Kutta, and spatially fth-order accurate WENO- 5Z scheme was used to perform implicit large eddy simulations. An immersed boundary method provides automated gridding for complex geometries and natural coupling to a block-structured Cartesian adaptive mesh re nement framework. Strong scaling studies using NASA's Pleiades supercomputer with up to 32k CPU cores and 4 billion compu- tational cells shows excellent scaling. Dynamic load balancing based on execution time on individual AMR blocks addresses irregular numerical cost associated with blocks con- taining boundaries. Limits to scaling beyond 32k cores are identi ed, and targeted code optimizations are discussed.

  1. Parallel Adaptive High-Order CFD Simulations Characterizing SOFIA Cavitiy Acoustics

    NASA Technical Reports Server (NTRS)

    Barad, Michael F.; Brehm, Christoph; Kiris, Cetin C.; Biswas, Rupak

    2015-01-01

    This paper presents large-scale MPI-parallel computational uid dynamics simulations for the Stratospheric Observatory for Infrared Astronomy (SOFIA). SOFIA is an airborne, 2.5-meter infrared telescope mounted in an open cavity in the aft fuselage of a Boeing 747SP. These simulations focus on how the unsteady ow eld inside and over the cavity interferes with the optical path and mounting structure of the telescope. A tempo- rally fourth-order accurate Runge-Kutta, and a spatially fth-order accurate WENO-5Z scheme were used to perform implicit large eddy simulations. An immersed boundary method provides automated gridding for complex geometries and natural coupling to a block-structured Cartesian adaptive mesh re nement framework. Strong scaling studies using NASA's Pleiades supercomputer with up to 32k CPU cores and 4 billion compu- tational cells shows excellent scaling. Dynamic load balancing based on execution time on individual AMR blocks addresses irregular numerical cost associated with blocks con- taining boundaries. Limits to scaling beyond 32k cores are identi ed, and targeted code optimizations are discussed.

  2. Self-assembly approach toward magnetic silica-type nanoparticles of different shapes from reverse block copolymer mesophases.

    PubMed

    Garcia, Carlos B W; Zhang, Yuanming; Mahajan, Surbhi; DiSalvo, Francis; Wiesner, Ulrich

    2003-11-05

    In the present study poly(isoprene-block-ethylene oxide), PI-b-PEO, block copolymers are used to structure iron oxide and silica precursors into reverse mesophases, which upon dissolution of the organic matrix lead to well-defined nanoparticles of spheres, cylinders, and plates based on the original structure of the mesophase prepared. The hybrid mesophases with sphere, cylinder, and lamellar morphologies containing the inorganic components in the minority phases are characterized through a combination of small-angle X-ray scattering (SAXS), transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM), and electron energy loss spectroscopy (EELS). After heat treatments the respective nanoparticles on mica surfaces are characterized by scanning force microscopy (SFM). X-ray diffraction (XRD) and superconducting quantum interference device (SQUID) magnetometer measurements are performed to demonstrate that the heat treatment leads to the formation of a magnetic gamma-Fe2O3 crystalline phase within the amorphous aluminosilicate. The results pave the way to functional, i.e., magnetic nanoparticles where the size, shape, and iron oxide concentration can be controlled opening a range of possible applications.

  3. Two new hybrid molybdenum arsenate derivative constructed from [As2Mo6O26]6- building: Synthesis, structural characterization and photocatalysis property

    NASA Astrophysics Data System (ADS)

    Zhang, Xiao; Luo, Xuan; Duan, Yuanling; Huang, Yanping; Zhang, Nanxi; Zhao, Liyan; Wu, Jie

    2017-08-01

    Two new inorganic-organic hybrid materials [Cu(enMe)2]2{(As2Mo6O26) [Cu(enMe)2]}·4H2O (1) and [As2Mo6(OH)2O24][Cu(H2O)2(phen)]2 (2) (enMe = 1,2'-propanediamine, phen = 1,10'-phenanthroline) based on [As2Mo6O26]6- building blocks, denoted as [As2Mo6], have been obtained by hydrothermal methods. 1 shows a 1-D straight chain structure constructed form [As2Mo6] building blocks and [Cu(enMe)2] complexes, and then extended to 3-D supramolecular network by lattice water via hydrogen bonds interactions. 2 exhibits a new 1-D covalent ribbon with large rectangular grids formed from [As2Mo6] building blocks connected by [Cu(H2O)2(phen)] complexes, then extended into 3-D supramolecular network via hydrogen bonds and π···π interactions. In additional, the photocatalytic activity for methylene blue degradation under visible-light irradiation of 2 was investigated.

  4. A transaction costs analysis of changing contractual relations in the English NHS.

    PubMed

    Marini, Giorgia; Street, Andrew

    2007-09-01

    The English National Health Service has replaced locally negotiated block contracting arrangements with a system of national prices to pay for hospital activity. This paper applies a transaction costs approach to quantify and analyse the nature of how contracting costs have changed as a consequence. Data collection was based on semi-structured interviews with key stakeholders from hospitals and Primary Care Trusts, which purchase hospital services. Replacing block contracting with activity based funding has led to lower costs of price negotiation, but these are outweighed by higher costs associated with volume control, of data collection, contract monitoring, and contract enforcement. There was consensus that the new contractual arrangements were preferable, but the benefits will have to be demonstrated formally in future.

  5. Rheological Design of Sustainable Block Copolymers

    NASA Astrophysics Data System (ADS)

    Mannion, Alexander M.

    Block copolymers are extremely versatile materials that microphase separate to give rise to a rich array of complex behavior, making them the ideal platform for the development of rheologically sophisticated soft matter. In line with growing environmental concerns of conventional plastics from petroleum feedstocks, this work focuses on the rheological design of sustainable block copolymers--those derived from renewable sources and are degradable--based on poly(lactide). Although commercially viable, poly(lactide) has a number of inherent deficiencies that result in a host of challenges that require both creative and practical solutions that are cost-effective and amenable to large-scale production. Specifically, this dissertation looks at applications in which both shear and extensional rheology dictate performance attributes, namely chewing gum, pressure-sensitive adhesives, and polymers for blown film extrusion. Structure-property relationships in the context of block polymer architecture, polymer composition, morphology, and branching are explored in depth. The basic principles and fundamental findings presented in this thesis are applicable to a broader range of substances that incorporate block copolymers for which rheology plays a pivotal role.

  6. Accelerating nuclear configuration interaction calculations through a preconditioned block iterative eigensolver

    NASA Astrophysics Data System (ADS)

    Shao, Meiyue; Aktulga, H. Metin; Yang, Chao; Ng, Esmond G.; Maris, Pieter; Vary, James P.

    2018-01-01

    We describe a number of recently developed techniques for improving the performance of large-scale nuclear configuration interaction calculations on high performance parallel computers. We show the benefit of using a preconditioned block iterative method to replace the Lanczos algorithm that has traditionally been used to perform this type of computation. The rapid convergence of the block iterative method is achieved by a proper choice of starting guesses of the eigenvectors and the construction of an effective preconditioner. These acceleration techniques take advantage of special structure of the nuclear configuration interaction problem which we discuss in detail. The use of a block method also allows us to improve the concurrency of the computation, and take advantage of the memory hierarchy of modern microprocessors to increase the arithmetic intensity of the computation relative to data movement. We also discuss the implementation details that are critical to achieving high performance on massively parallel multi-core supercomputers, and demonstrate that the new block iterative solver is two to three times faster than the Lanczos based algorithm for problems of moderate sizes on a Cray XC30 system.

  7. Enhancing the performance of blue GaN-based light emitting diodes with double electron blocking layers

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

    Guo, Yao; Liang, Meng; Fu, Jiajia

    2015-03-15

    In this work, novel double Electron Blocking Layers for InGaN/GaN multiple quantum wells light-emitting diodes were proposed to mitigate the efficiency droop at high current density. The band diagram and carriers distributions were investigated numerically. The results indicate that due to a newly formed holes stack in the p-GaN near the active region, the hole injection has been improved and an uniform carriers distribution can be achieved. As a result, in our new structure with double Electron Blocking Layers, the efficiency droop has been reduced to 15.5 % in comparison with 57.3 % for the LED with AlGaN EBL atmore » the current density of 100 A/cm{sup 2}.« less

  8. An instance theory of associative learning.

    PubMed

    Jamieson, Randall K; Crump, Matthew J C; Hannah, Samuel D

    2012-03-01

    We present and test an instance model of associative learning. The model, Minerva-AL, treats associative learning as cued recall. Memory preserves the events of individual trials in separate traces. A probe presented to memory contacts all traces in parallel and retrieves a weighted sum of the traces, a structure called the echo. Learning of a cue-outcome relationship is measured by the cue's ability to retrieve a target outcome. The theory predicts a number of associative learning phenomena, including acquisition, extinction, reacquisition, conditioned inhibition, external inhibition, latent inhibition, discrimination, generalization, blocking, overshadowing, overexpectation, superconditioning, recovery from blocking, recovery from overshadowing, recovery from overexpectation, backward blocking, backward conditioned inhibition, and second-order retrospective revaluation. We argue that associative learning is consistent with an instance-based approach to learning and memory.

  9. Magnitude estimation and runout analysis of a rockslide for the construction of a defensive structure

    NASA Astrophysics Data System (ADS)

    Gigli, G.; Casagli, N.; Lombardi, L.; Nocentini, M.; Balducci, M.; Venanti, L.

    2009-04-01

    In the past few years the Maiolica (micritic limestone) quarry of Torgiovannetto (Perugia, Italy) has suffered an increasing amount of rockfalls. The rock mass has loosened progressively and a perimetral crack longer than 100 meters has appeared. The huge block bounded by this crack, two lateral discontinuities and a stratigraphic layer, threatens two roads at the base of the slope. Since these are very important and busy traffic routes the Department of Earth Sciences of the University of Firenze performed magnitude estimations and runout analyses regarding two different aspects: 1) investigate the trajectories of single falling blocks and; 2) forecast the runout distance and the debris intensity distribution in case a large rockslide occurs. The magnitude of a landslide is, actually, the most important input parameter for correctly estimating the trajectory, the runout distance and the kinetic energy of a landslide. A detailed and updated knowledge of the actual morphological conditions is a good starting point for defining as accurately as possible the extent of a moving block. Due to the very high urgency and precision required, a detailed survey of the quarry area has been performed by means of a High Accuracy & Long Range 3D laser scanner (RIEGLE, LMS-Z.420i). In order to avoid shadow zones and to obtain a comprehensive digital elevation model of the quarry area, a total of more than 30 million points were taken from three different scan positions. The resulting point cloud was dense enough to reveal the main structural features of the rock mass, including the discontinuities bounding the moving block, which has a calculated volume of 180 000 m3. With the aim of confirming the block volume and assessing the deformational field of the moving mass, a multitemporal ground-based interferometric SAR survey was performed. The results of the survey precisely confirm the geometry of the unstable block and also indicate that the displacements decrease from E to W, due to the greater lateral friction in the western portion of the wedge. This deformational behaviour has been confirmed by a wireless real time monitoring system installed for the time of failure forecast. Laboratory tests and stability analyses of the unstable wedge allowed us to hypothesize a sudden and brittle failure behavior, which can be associated to a long runout distance. Both empirical (energy line approach) and numerical methods (DAN-W and DAN3D softwares) were employed for estimating the runout distance and debris intensity distribution associated with the failure of the main block. The results of this analysis indicate that the potential rockslide will likely reach the nearest road. The estimated velocity, debris depth, and kinetic energy of the moving mass can be used to project defensive structures at the base of the artificial slope.

  10. An Ap-Structure with Finslerian Flavor I:. the Principal Idea

    NASA Astrophysics Data System (ADS)

    Wanas, M. I.

    A geometric structure (FAP-structure), having both absolute parallelism and Finsler properties, is constructed. The building blocks of this structure are assumed to be functions of position and direction. A nonlinear connection emerges naturally and is defined in terms of the building blocks of the structure. Two linear connections, one of Berwald type and the other of the Cartan type, are defined using the nonlinear connection of the FAP. Both linear connections are nonsymmetric and consequently admit torsion. A metric tensor is defined in terms of the building blocks of the structure. The condition for this metric to be a Finslerian one is obtained. Also, the condition for an FAP-space to be an AP-one is given.

  11. Random and Block Sulfonated Polyaramides as Advanced Proton Exchange Membranes

    DOE PAGES

    Kinsinger, Corey L.; Liu, Yuan; Liu, Feilong; ...

    2015-10-09

    We present here the experimental and computational characterization of two novel copolyaramide proton exchange membranes (PEMs) with higher conductivity than Nafion at relatively high temperatures, good mechanical properties, high thermal stability, and the capability to operate in low humidity conditions. The random and block copolyaramide PEMs are found to possess different ion exchange capacities (IEC) in addition to subtle structural and morphological differences, which impact the stability and conductivity of the membranes. SAXS patterns indicate the ionomer peak for the dry block copolymer resides at q = 0.1 Å –1, which increases in amplitude when initially hydrated to 25% relativemore » humidity, but then decrease in amplitude with additional hydration. This pattern is hypothesized to signal the transport of water into the polymer matrix resulting in a reduced degree of phase separation. Coupled to these morphological changes, the enhanced proton transport characteristics and structural/mechanical stability for the block copolymer are hypothesized to be primarily due to the ordered structure of ionic clusters that create connected proton transport pathways while reducing swelling upon hydration. Interestingly, the random copolymer did not possess an ionomer peak at any of the hydration levels investigated, indicating a lack of any significant ionomer structure. The random copolymer also demonstrated higher proton conductivity than the block copolymer, which is opposite to the trend normally seen in polymer membranes. However, it has reduced structural/mechanical stability as compared to the block copolymer. In conclusion, this reduction in stability is due to the random morphology formed by entanglements of polymer chains and the adverse swelling characteristics upon hydration. Therefore, the block copolymer with its enhanced proton conductivity characteristics, as compared to Nafion, and favorable structural/mechanical stability, as compared to the random copolymer, represents a viable alternative to current proton exchange membranes.« less

  12. Fabrication of Carbonate Apatite Block through a Dissolution-Precipitation Reaction Using Calcium Hydrogen Phosphate Dihydrate Block as a Precursor.

    PubMed

    Tsuru, Kanji; Yoshimoto, Ayami; Kanazawa, Masayuki; Sugiura, Yuki; Nakashima, Yasuharu; Ishikawa, Kunio

    2017-03-31

    Carbonate apatite (CO₃Ap) block, which is a bone replacement used to repair defects, was fabricated through a dissolution-precipitation reaction using a calcium hydrogen phosphate dihydrate (DCPD) block as a precursor. When the DCPD block was immersed in NaHCO₃ or Na₂CO₃ solution at 80 °C, DCPD converted to CO₃Ap within 3 days. β-Tricalcium phosphate was formed as an intermediate phase, and it was completely converted to CO₃Ap within 2 weeks when the DCPD block was immersed in Na₂CO₃ solution. Although the crystal structures of the DCPD and CO₃Ap blocks were different, the macroscopic structure was maintained during the compositional transformation through the dissolution-precipitation reaction. CO₃Ap block fabricated in NaHCO₃ or Na₂CO₃ solution contained 12.9 and 15.8 wt % carbonate, respectively. The diametral tensile strength of the CO₃Ap block was 2 MPa, and the porosity was approximately 57% regardless of the carbonate solution. DCPD is a useful precursor for the fabrication of CO₃Ap block.

  13. The influence of polarity of additive molecules on micelle structures of polystyrene-block-poly(4-vinylpyridine) in the fabrication of nano-porous templates.

    PubMed

    Chua, Kee Sze; Koh, Ai Peng; Lam, Yeng Ming

    2010-11-01

    Block copolymers are useful for in situ synthesis of nanoparticles as well as producing nanoporous templates. As such, the effects of precursors on the block copolymer micelle structure is important. In this study, we investigate the effects of polarity of molecules introduced into block copolymer micelle cores on the micelle structure. The molecular dipole moment of the additive molecules has been evaluated and their effects on the block copolymer micelles investigated using light scattering spectroscopy, small-angle X-ray scattering, transmission electron microscopy and atomic force microscopy. The molecule with the largest dipole moment resulted in spherical structures with a polydispersity of less than 0.06 in a fully translational diffusion system. Surprisingly, the less polar additive molecules produced elongated micelles and the aspect ratio increases with decreasing polarity. The change in structure from spherical to elongated structure was attributed to P4VP chain extension, where compounds with polarity most similar to P4VP induce the most chain extension. The second virial coefficients of the solutions with elongated micelles are lower than that for spherical micelle systems by up to one order in magnitude, indicating a strong tendency for micelles to coalesce. On rinsing the spin-cast films, pores were obtained from spherical micelles and ridges from elongated micelles, suggesting a viable alternative for morphology modification using mild conditions where external annealing treatments to the film are not preferred. The knowledge of polarity effects of additive molecules on micelle structure has wider implications for supramolecular block copolymer systems where, depending on the application requirements, changes to the shape of the micelle structure can be induced or avoided. Copyright 2010 Elsevier Inc. All rights reserved.

  14. Advanced aircraft service life monitoring method via flight-by-flight load spectra

    NASA Astrophysics Data System (ADS)

    Lee, Hongchul

    This research is an effort to understand current method and to propose an advanced method for Damage Tolerance Analysis (DTA) for the purpose of monitoring the aircraft service life. As one of tasks in the DTA, the current indirect Individual Aircraft Tracking (IAT) method for the F-16C/D Block 32 does not properly represent changes in flight usage severity affecting structural fatigue life. Therefore, an advanced aircraft service life monitoring method based on flight-by-flight load spectra is proposed and recommended for IAT program to track consumed fatigue life as an alternative to the current method which is based on the crack severity index (CSI) value. Damage Tolerance is one of aircraft design philosophies to ensure that aging aircrafts satisfy structural reliability in terms of fatigue failures throughout their service periods. IAT program, one of the most important tasks of DTA, is able to track potential structural crack growth at critical areas in the major airframe structural components of individual aircraft. The F-16C/D aircraft is equipped with a flight data recorder to monitor flight usage and provide the data to support structural load analysis. However, limited memory of flight data recorder allows user to monitor individual aircraft fatigue usage in terms of only the vertical inertia (NzW) data for calculating Crack Severity Index (CSI) value which defines the relative maneuver severity. Current IAT method for the F-16C/D Block 32 based on CSI value calculated from NzW is shown to be not accurate enough to monitor individual aircraft fatigue usage due to several problems. The proposed advanced aircraft service life monitoring method based on flight-by-flight load spectra is recommended as an improved method for the F-16C/D Block 32 aircraft. Flight-by-flight load spectra was generated from downloaded Crash Survival Flight Data Recorder (CSFDR) data by calculating loads for each time hack in selected flight data utilizing loads equations. From the comparison of interpolated fatigue life using CSI value and fatigue test results, it is obvious that proposed advanced IAT method via flight-by-flight load spectra is more reliable and accurate than current IAT method. Therefore, the advanced aircraft service life monitoring method based on flight-by-flight load spectra not only monitors the individual aircraft consumed fatigue life for inspection but also ensures the structural reliability of aging aircrafts throughout their service periods.

  15. Structural implications of hERG K+ channel block by a high-affinity minimally structured blocker

    PubMed Central

    Helliwell, Matthew V.; Zhang, Yihong; El Harchi, Aziza; Du, Chunyun; Hancox, Jules C.; Dempsey, Christopher E.

    2018-01-01

    Cardiac potassium channels encoded by human ether-à-go-go–related gene (hERG) are major targets for structurally diverse drugs associated with acquired long QT syndrome. This study characterized hERG channel inhibition by a minimally structured high-affinity hERG inhibitor, Cavalli-2, composed of three phenyl groups linked by polymethylene spacers around a central amino group, chosen to probe the spatial arrangement of side chain groups in the high-affinity drug-binding site of the hERG pore. hERG current (IhERG) recorded at physiological temperature from HEK293 cells was inhibited with an IC50 of 35.6 nm with time and voltage dependence characteristic of blockade contingent upon channel gating. Potency of Cavalli-2 action was markedly reduced for attenuated inactivation mutants located near (S620T; 54-fold) and remote from (N588K; 15-fold) the channel pore. The S6 Y652A and F656A mutations decreased inhibitory potency 17- and 75-fold, respectively, whereas T623A and S624A at the base of the selectivity filter also decreased potency (16- and 7-fold, respectively). The S5 helix F557L mutation decreased potency 10-fold, and both F557L and Y652A mutations eliminated voltage dependence of inhibition. Computational docking using the recent cryo-EM structure of an open channel hERG construct could only partially recapitulate experimental data, and the high dependence of Cavalli-2 block on Phe-656 is not readily explainable in that structure. A small clockwise rotation of the inner (S6) helix of the hERG pore from its configuration in the cryo-EM structure may be required to optimize Phe-656 side chain orientations compatible with high-affinity block. PMID:29545312

  16. Synthesis of poly(N-isopropylacrylamide)-co-poly(phenylboronate ester) acrylate and study on their glucose-responsive behavior.

    PubMed

    Yao, Yuan; Shen, Heyun; Zhang, Guanghui; Yang, Jing; Jin, Xu

    2014-10-01

    We introduced thermo-sensitive poly(N-isopropylacrylamide) (PNIPAM) into the polymer structure of poly(ethylene glycol)-block-poly(phenylboronate ester) acrylate (MPEG-block-PPBDEMA) by block and random polymerization pathways in order to investigate the effect of polymer architecture on the glucose-responsiveness and enhance their insulin release controllability. By following the structure, the continuous PNIPAM shell of the triblock polymer MPEG-block-PNIPAM-block-PPBDEMA collapsing on the glucose-responsive PPBDEMA core formed the polymeric micelles with a core-shell-corona structure, and MPEG-block-(PNIPAM-rand-PPBDEMA) exhibited core-corona micelles in which the hydrophobic core consisted of PNIPAM and PPBDEMA segments when the environmental temperature was increased above low critical solution temperature (LCST) of PNIPAM. The micellar morphologies can be precisely controlled by temperature change between 15 and 37°C. As a result, the introduction of PNIPAM greatly enhanced the overall stability of insulin encapsulated in the polymeric micelles in the absence of glucose over incubation 80 h at 37°C. Comparing to MPEG-block-PNIPAM-block-PPBDEMA, the nanocarriers from MPEG-block-(PNIPAM-rand-PPBDEMA) showed great insulin release behavior which is zero insulin release without glucose, low release at normal blood glucose concentration (1.0 mg/mL). Therefore, these nanocarriers may be served as promising self-regulated insulin delivery system for diabetes treatment. Copyright © 2014 Elsevier Inc. All rights reserved.

  17. An outline of graphical Markov models in dentistry.

    PubMed

    Helfenstein, U; Steiner, M; Menghini, G

    1999-12-01

    In the usual multiple regression model there is one response variable and one block of several explanatory variables. In contrast, in reality there may be a block of several possibly interacting response variables one would like to explain. In addition, the explanatory variables may split into a sequence of several blocks, each block containing several interacting variables. The variables in the second block are explained by those in the first block; the variables in the third block by those in the first and the second block etc. During recent years methods have been developed allowing analysis of problems where the data set has the above complex structure. The models involved are called graphical models or graphical Markov models. The main result of an analysis is a picture, a conditional independence graph with precise statistical meaning, consisting of circles representing variables and lines or arrows representing significant conditional associations. The absence of a line between two circles signifies that the corresponding two variables are independent conditional on the presence of other variables in the model. An example from epidemiology is presented in order to demonstrate application and use of the models. The data set in the example has a complex structure consisting of successive blocks: the variable in the first block is year of investigation; the variables in the second block are age and gender; the variables in the third block are indices of calculus, gingivitis and mutans streptococci and the final response variables in the fourth block are different indices of caries. Since the statistical methods may not be easily accessible to dentists, this article presents them in an introductory form. Graphical models may be of great value to dentists in allowing analysis and visualisation of complex structured multivariate data sets consisting of a sequence of blocks of interacting variables and, in particular, several possibly interacting responses in the final block.

  18. Controlled disulfonated poly(arylene ether sulfone) multiblock copolymers for direct methanol fuel cells.

    PubMed

    Li, Qing; Chen, Yu; Rowlett, Jarrett R; McGrath, James E; Mack, Nathan H; Kim, Yu Seung

    2014-04-23

    Structure-property-performance relationships of disulfonated poly(arylene ether sulfone) multiblock copolymer membranes were investigated for their use in direct methanol fuel cell (DMFC) applications. Multiple series of reactive polysulfone, polyketone, and polynitrile hydrophobic block segments having different block lengths and molecular composition were synthesized and reacted with a disulfonated poly(arylene ether sulfone) hydrophilic block segment by a coupling reaction. Large-scale morphological order of the multiblock copolymers evolved with the increase of block size that gave notable influence on mechanical toughness, water uptake, and proton/methanol transport. Chemical structural changes of the hydrophobic blocks through polar group, fluorination, and bisphenol type allowed further control of the specific properties. DMFC performance was analyzed to elicit the impact of structural variations of the multiblock copolymers. Finally, DMFC performances of selected multiblock copolymers were compared against that of the industrial standard Nafion in the DMFC system.

  19. Hydrogen Bond Induces Hierarchical Self-Assembly in Liquid-Crystalline Block Copolymers.

    PubMed

    Huang, Shuai; Pang, Linlin; Chen, Yuxuan; Zhou, Liming; Fang, Shaoming; Yu, Haifeng

    2018-03-01

    Microphase-separated structures of block copolymers (BCs) with a size of sub-10 nm are usually obtained by hydrogen-bond-induced self-assembly of BCs through doping with small molecules as functional additives. Here, fabrication of hierarchically self-assembled sub-10 nm structures upon microphase separation of amphiphilic liquid-crystalline BCs (LCBCs) at the existence of hydrogen bonds but without any dopants is reported. The newly introduced urethane groups in the side chain of the hydrophobic block of LCBCs interact with the ether groups of the hydrophilic poly(ethylene oxide) (PEO) block, leading to imperfect crystallization of the PEO blocks. Both crystalline and amorphous domains coexist in the separated PEO phase, enabling a lamellar structure to appear inside the PEO nanocylinders. This provides an elegant method to fabricate controllable sub-10 nm microstructures in well-defined polymer systems without the introduction of any dopants. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. [Interest of ultrasonographic guidance in paediatric regional anaesthesia].

    PubMed

    Dadure, C; Raux, O; Rochette, A; Capdevila, X

    2009-10-01

    The use of ultrasonographic guidance for regional anaesthesia has known recently a big interest in children in recent years. The linear ultrasound probes with a 25 mm active surface area (or probes with 38 mm active surface area in older children), with high sound frequencies in the range 8-14 MHz, allow a good compromise between excellent resolution for superficial structure and good penetration depths. In children, the easiest ultrasound guided blocks are axillar blocks, femoral blocks, fascia iliaca compartment blocks, ilio-inguinal blocks and para-umbilical blocks, caudal blocks. They permit a safe and easy learning curve of these techniques. The main advantage of ultrasound guided regional anaesthesia is the visualization of different anatomical structures and the approximate localization of the tip of needle. The other advantages for ultrasound guided peripheral nerve blocks in children are: faster onset time of sensory and motor block, longer duration of sensory blockade, increase of blockade quality and reduction of local anesthetic injection. The use of ultrasonographic guidance for central block allows to visualize different structures as well as spine and his content. Spinous process, ligament flavum, dura mater, conus medullaris and cerebrospinal fluid are identifiable, and give some information on spine, epidural space and the depth between epidural space and skin. At last, in caudal block, ultrasounds permit to evaluate the anatomy of caudal epidural space, especially the relation of the sacral hiatus to the dural sac and the search of occult spinal dysraphism. Benefit of this technique is the visualization of targeted nerves or spaces and the spread of injected local anaesthetic.

  1. Evidences for Skeletal Structures in the Ocean from the Images Analyzed by Multilevel Dynamical Contrasting Method

    NASA Astrophysics Data System (ADS)

    Rantsev-Kartinov, Valentin A.

    2004-11-01

    An analysis of databases of photographic images of ocean's surface, taken from various altitudes and for various types of rough ocean surface, revealed the presence of an ocean's skeletal structures (OSS) = http://www.arxiv.org/ftp/physics/papers/0401/0401139.pdf [1] Rantsev-Kartinov V.A., Preprint, which exhibit a tendency toward self-similarity of structuring at various length scales (i.e., within various ``generations''). The topology of the OSS appears to be identical to that of skeletal structures which have been formerly found in a wide range of length scales, media and for various phenomena (Phys. Lett. A, 2002, 306). The typical OSS consists of separate identical blocks which are linked together to form a network. Two types of such blocks are found: (i) a coaxial tubular (CT) structures with internal radial bonds, and (ii) a cartwheel-like structures, located either on an axle or in the edges of the CT blocks. The OSSs differ from the formerly found SSs only by the fact that OSS, in their interior, are filled in with closely packed OSSs of a smaller size. We specially discuss the phenomenon of skeletal blocks in the form of vertically/horizontally oriented floating cylinders. The size of these observed blocks is shown to grow with increasing rough water.

  2. Computing Aerodynamic Performance of a 2D Iced Airfoil: Blocking Topology and Grid Generation

    NASA Technical Reports Server (NTRS)

    Chi, X.; Zhu, B.; Shih, T. I.-P.; Slater, J. W.; Addy, H. E.; Choo, Yung K.; Lee, Chi-Ming (Technical Monitor)

    2002-01-01

    The ice accrued on airfoils can have enormously complicated shapes with multiple protruded horns and feathers. In this paper, several blocking topologies are proposed and evaluated on their ability to produce high-quality structured multi-block grid systems. A transition layer grid is introduced to ensure that jaggedness on the ice-surface geometry do not to propagate into the domain. This is important for grid-generation methods based on hyperbolic PDEs (Partial Differential Equations) and algebraic transfinite interpolation. A 'thick' wrap-around grid is introduced to ensure that grid lines clustered next to solid walls do not propagate as streaks of tightly packed grid lines into the interior of the domain along block boundaries. For ice shapes that are not too complicated, a method is presented for generating high-quality single-block grids. To demonstrate the usefulness of the methods developed, grids and CFD solutions were generated for two iced airfoils: the NLF0414 airfoil with and without the 623-ice shape and the B575/767 airfoil with and without the 145m-ice shape. To validate the computations, the computed lift coefficients as a function of angle of attack were compared with available experimental data. The ice shapes and the blocking topologies were prepared by NASA Glenn's SmaggIce software. The grid systems were generated by using a four-boundary method based on Hermite interpolation with controls on clustering, orthogonality next to walls, and C continuity across block boundaries. The flow was modeled by the ensemble-averaged compressible Navier-Stokes equations, closed by the shear-stress transport turbulence model in which the integration is to the wall. All solutions were generated by using the NPARC WIND code.

  3. Molecular Building Block-Based Electronic Charges for High-Throughput Screening of Metal-Organic Frameworks for Adsorption Applications.

    PubMed

    Argueta, Edwin; Shaji, Jeena; Gopalan, Arun; Liao, Peilin; Snurr, Randall Q; Gómez-Gualdrón, Diego A

    2018-01-09

    Metal-organic frameworks (MOFs) are porous crystalline materials with attractive properties for gas separation and storage. Their remarkable tunability makes it possible to create millions of MOF variations but creates the need for fast material screening to identify promising structures. Computational high-throughput screening (HTS) is a possible solution, but its usefulness is tied to accurate predictions of MOF adsorption properties. Accurate adsorption simulations often require an accurate description of electrostatic interactions, which depend on the electronic charges of the MOF atoms. HTS-compatible methods to assign charges to MOF atoms need to accurately reproduce electrostatic potentials (ESPs) and be computationally affordable, but current methods present an unsatisfactory trade-off between computational cost and accuracy. We illustrate a method to assign charges to MOF atoms based on ab initio calculations on MOF molecular building blocks. A library of building blocks with built-in charges is thus created and used by an automated MOF construction code to create hundreds of MOFs with charges "inherited" from the constituent building blocks. The molecular building block-based (MBBB) charges are similar to REPEAT charges-which are charges that reproduce ESPs obtained from ab initio calculations on crystallographic unit cells of nanoporous crystals-and thus similar predictions of adsorption loadings, heats of adsorption, and Henry's constants are obtained with either method. The presented results indicate that the MBBB method to assign charges to MOF atoms is suitable for use in computational high-throughput screening of MOFs for applications that involve adsorption of molecules such as carbon dioxide.

  4. Deep Probe: Investigating the lithosphere of western North America with refraction seismology

    NASA Astrophysics Data System (ADS)

    Gorman, Andrew Robert

    The Laurentian Craton, composed of the exposed Canadian Shield ringed by sediment-covered platforms, is the Precambrian heart of North America. The craton can be divided into several provinces representing ancient Archean blocks and the suture regions which stitched them together. In western Canada, Montana and Wyoming, the general distribution of Precambrian cratonic elements has been established by previous potential field studies combined with the analysis of basement rocks extracted from a small number of exploration drill holes that penetrated the overlying sedimentary basin, and from limited outcrops in southern Montana and Wyoming. The major blocks identified in this region include the Archean Hearne (mostly beneath Alberta) and Wyoming (beneath Montana and Wyoming) Provinces. A third block, the Medicine Hat Block, often interpreted to be the southernmost part of the Hearne Province, is considered independent in this study. The objectives of this thesis are to determine the velocity structure and characteristics of the crust and sub-crustal lithospheric mantle beneath the three Archean domains and the relationships among them to further understanding of the tectonic development of cratonic western North America. These objectives are met through interpretation of data from the Deep Probe/SAREX seismic refraction experiment of 1995, the largest of its type ever undertaken on the continent. Twenty large chemical explosions were detonated along a 3000-km-long profile running from Great Slave Lake to southern New Mexico and recorded at ˜2000 closely spaced seismograph stations between central Alberta and northern New Mexico. Interpretations, of increasing complexity, are based on: (1) the tau-p downward continuation of individual shot records, (2) a ray-theoretical travel-time inversion with Earth curvature considerations, and (3) detailed modelling of specific features with a finite difference wave propagation method. Interpretations of velocities and structures are made to depths as great as 150 km. From features of the crustal structure and their correspondence with two north-dipping relict subduction zones in the upper mantle, the boundaries between the three major Archean blocks are delineated and associated with the Vulcan Structure and Great Falls Tectonic Zone, two poorly understood tectonic features in the region. A prominent 10-to-30 km thick high velocity layer at the base of the Wyoming Province and Medicine Hat Block is interpreted to represent Proterozoic crustal underplating and alteration. The composition and physical properties of the crust-mantle boundary, the relict subduction zones and a heterogeneous upper mantle layer lying between depths of 100 km and 140 km are investigated to further understand lithospheric development in this region. The seismic interpretation is combined with previous work to develop a revised scenario for the tectonic assembly of western Laurentia.

  5. High-Resolution Crystal Structure of a Silver(I)-RNA Hybrid Duplex Containing Watson-Crick-like C-Silver(I)-C Metallo-Base Pairs.

    PubMed

    Kondo, Jiro; Tada, Yoshinari; Dairaku, Takenori; Saneyoshi, Hisao; Okamoto, Itaru; Tanaka, Yoshiyuki; Ono, Akira

    2015-11-02

    Metallo-base pairs have been extensively studied for applications in nucleic acid-based nanodevices and genetic code expansion. Metallo-base pairs composed of natural nucleobases are attractive because nanodevices containing natural metallo-base pairs can be easily prepared from commercially available sources. Previously, we have reported a crystal structure of a DNA duplex containing T-Hg(II)-T base pairs. Herein, we have determined a high-resolution crystal structure of the second natural metallo-base pair between pyrimidine bases C-Ag(I)-C formed in an RNA duplex. One Ag(I) occupies the center between two cytosines and forms a C-Ag(I)-C base pair through N3-Ag(I)-N3 linear coordination. The C-Ag(I)-C base pair formation does not disturb the standard A-form conformation of RNA. Since the C-Ag(I)-C base pair is structurally similar to the canonical Watson-Crick base pairs, it can be a useful building block for structure-based design and fabrication of nucleic acid-based nanodevices. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Facile access to unnatural dipeptide-alcohols based on cis-2,5-disubstituted pyrrolidines.

    PubMed

    Jia, Yan-Yan; Li, Xiao-Ye; Wang, Ping-An; Wen, Ai-Dong

    2015-02-11

    Well-defined unnatural dipeptide-alcohols based on a cis-2,5-disubstitued pyrrolidine backbone were synthesized from commercially available starting materials meso-diethyl-2,5-dibromoadipate, (S)-(-)-1-phenylethylamine, and phenylalaninol. The structures of these unnatural dipeptide-alcohols are supported by HRMS, 1H- and 13C-NMR spectroscopy. These unnatural dipeptide-alcohols can act as building blocks for peptidomimetics.

  7. Biodegradable polydepsipeptides.

    PubMed

    Feng, Yakai; Guo, Jintang

    2009-02-01

    This paper reviews the synthesis, characterization, biodegradation and usage of bioresorbable polymers based on polydepsipeptides. The ring-opening polymerization of morpholine-2,5-dione derivatives using organic Sn and enzyme lipase is discussed. The dependence of the macroscopic properties of the block copolymers on their structure is also presented. Bioresorbable polymers based on polydepsipeptides could be used as biomaterials in drug controlled release, tissue engineering scaffolding and shape-memory materials.

  8. Comparison of the effect of land-sea thermal contrast on interdecadal variations in winter and summer blockings

    NASA Astrophysics Data System (ADS)

    He, Yongli; Huang, Jianping; Li, Dongdong; Xie, Yongkun; Zhang, Guolong; Qi, Yulei; Wang, Shanshan; Totz, Sonja

    2017-11-01

    The influence of winter and summer land-sea surface thermal contrast on blocking for 1948-2013 is investigated using observations and the coupled model intercomparison project outputs. The land-sea index (LSI) is defined to measure the changes of zonal asymmetric thermal forcing under global warming. The summer LSI shows a slower increasing trend than winter during this period. For the positive of summer LSI, the EP flux convergence induced by the land-sea thermal forcing in the high latitude becomes weaker than normal, which induces positive anomaly of zonal-mean westerly and double-jet structure. Based on the quasiresonance amplification mechanism, the narrow and reduced westerly tunnel between two jet centers provides a favor environment for more frequent blocking. Composite analysis demonstrates that summer blocking shows an increasing trend of event numbers and a decreasing trend of durations. The numbers of the short-lived blocking persisting for 5-9 days significantly increases and the numbers of the long-lived blocking persisting for longer than 10 days has a weak increase than that in negative phase of summer LSI. The increasing transient wave activities induced by summer LSI is responsible for the decreasing duration of blockings. The increasing blocking due to summer LSI can further strengthen the continent warming and increase the summer LSI, which forms a positive feedback. The opposite dynamical effect of LSI on summer and winter blocking are discussed and found that the LSI-blocking negative feedback partially reduces the influence of the above positive feedback and induce the weak summer warming rate.

  9. Role of Polyalanine Domains in -Sheet Formation in Spider Silk Block Copolymers

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

    Rabotyagova, O.; Cebe, P; Kaplan, D

    2010-01-01

    Genetically engineered spider silk-like block copolymers were studied to determine the influence of polyalanine domain size on secondary structure. The role of polyalanine block distribution on {beta}-sheet formation was explored using FT-IR and WAXS. The number of polyalanine blocks had a direct effect on the formation of crystalline {beta}-sheets, reflected in the change in crystallinity index as the blocks of polyalanines increased. WAXS analysis confirmed the crystalline nature of the sample with the largest number of polyalanine blocks. This approach provides a platform for further exploration of the role of specific amino acid chemistries in regulating the assembly of {beta}-sheetmore » secondary structures, leading to options to regulate material properties through manipulation of this key component in spider silks.« less

  10. Good Trellises for IC Implementation of Viterbi Decoders for Linear Block Codes

    NASA Technical Reports Server (NTRS)

    Moorthy, Hari T.; Lin, Shu; Uehara, Gregory T.

    1997-01-01

    This paper investigates trellis structures of linear block codes for the integrated circuit (IC) implementation of Viterbi decoders capable of achieving high decoding speed while satisfying a constraint on the structural complexity of the trellis in terms of the maximum number of states at any particular depth. Only uniform sectionalizations of the code trellis diagram are considered. An upper-bound on the number of parallel and structurally identical (or isomorphic) subtrellises in a proper trellis for a code without exceeding the maximum state complexity of the minimal trellis of the code is first derived. Parallel structures of trellises with various section lengths for binary BCH and Reed-Muller (RM) codes of lengths 32 and 64 are analyzed. Next, the complexity of IC implementation of a Viterbi decoder based on an L-section trellis diagram for a code is investigated. A structural property of a Viterbi decoder called add-compare-select (ACS)-connectivity which is related to state connectivity is introduced. This parameter affects the complexity of wire-routing (interconnections within the IC). The effect of five parameters namely: (1) effective computational complexity; (2) complexity of the ACS-circuit; (3) traceback complexity; (4) ACS-connectivity; and (5) branch complexity of a trellis diagram on the very large scale integration (VISI) complexity of a Viterbi decoder is investigated. It is shown that an IC implementation of a Viterbi decoder based on a nonminimal trellis requires less area and is capable of operation at higher speed than one based on the minimal trellis when the commonly used ACS-array architecture is considered.

  11. Good trellises for IC implementation of viterbi decoders for linear block codes

    NASA Technical Reports Server (NTRS)

    Lin, Shu; Moorthy, Hari T.; Uehara, Gregory T.

    1996-01-01

    This paper investigates trellis structures of linear block codes for the IC (integrated circuit) implementation of Viterbi decoders capable of achieving high decoding speed while satisfying a constraint on the structural complexity of the trellis in terms of the maximum number of states at any particular depth. Only uniform sectionalizations of the code trellis diagram are considered. An upper bound on the number of parallel and structurally identical (or isomorphic) subtrellises in a proper trellis for a code without exceeding the maximum state complexity of the minimal trellis of the code is first derived. Parallel structures of trellises with various section lengths for binary BCH and Reed-Muller (RM) codes of lengths 32 and 64 are analyzed. Next, the complexity of IC implementation of a Viterbi decoder based on an L-section trellis diagram for a code is investigated. A structural property of a Viterbi decoder called ACS-connectivity which is related to state connectivity is introduced. This parameter affects the complexity of wire-routing (interconnections within the IC). The effect of five parameters namely: (1) effective computational complexity; (2) complexity of the ACS-circuit; (3) traceback complexity; (4) ACS-connectivity; and (5) branch complexity of a trellis diagram on the VLSI complexity of a Viterbi decoder is investigated. It is shown that an IC implementation of a Viterbi decoder based on a non-minimal trellis requires less area and is capable of operation at higher speed than one based on the minimal trellis when the commonly used ACS-array architecture is considered.

  12. Software reliability through fault-avoidance and fault-tolerance

    NASA Technical Reports Server (NTRS)

    Vouk, Mladen A.; Mcallister, David F.

    1992-01-01

    Accomplishments in the following research areas are summarized: structure based testing, reliability growth, and design testability with risk evaluation; reliability growth models and software risk management; and evaluation of consensus voting, consensus recovery block, and acceptance voting. Four papers generated during the reporting period are included as appendices.

  13. Properties Of Carbon/Carbon and Carbon/Phenolic Composites

    NASA Technical Reports Server (NTRS)

    Mathis, John R.; Canfield, A. R.

    1993-01-01

    Report presents data on physical properties of carbon-fiber-reinforced carbon-matrix and phenolic-matrix composite materials. Based on tests conducted on panels, cylinders, blocks, and formed parts. Data used by designers to analyze thermal-response and stress levels and develop structural systems ensuring high reliability at minimum weight.

  14. Cooperative storage of shared files in a parallel computing system with dynamic block size

    DOEpatents

    Bent, John M.; Faibish, Sorin; Grider, Gary

    2015-11-10

    Improved techniques are provided for parallel writing of data to a shared object in a parallel computing system. A method is provided for storing data generated by a plurality of parallel processes to a shared object in a parallel computing system. The method is performed by at least one of the processes and comprises: dynamically determining a block size for storing the data; exchanging a determined amount of the data with at least one additional process to achieve a block of the data having the dynamically determined block size; and writing the block of the data having the dynamically determined block size to a file system. The determined block size comprises, e.g., a total amount of the data to be stored divided by the number of parallel processes. The file system comprises, for example, a log structured virtual parallel file system, such as a Parallel Log-Structured File System (PLFS).

  15. Evolution of crystalline target rocks and impactites in the chesapeake bay impact structure, ICDP-USGS eyreville B core

    USGS Publications Warehouse

    Horton, J. Wright; Kunk, Michael J.; Belkin, Harvey E.; Aleinikoff, John N.; Jackson, John C.; Chou, I.-Ming

    2009-01-01

    The 1766-m-deep Eyreville B core from the late Eocene Chesapeake Bay impact structure includes, in ascending order, a lower basement-derived section of schist and pegmatitic granite with impact breccia dikes, polymict impact breccias, and cataclas tic gneiss blocks overlain by suevites and clast-rich impact melt rocks, sand with an amphibolite block and lithic boulders, and a 275-m-thick granite slab overlain by crater-fill sediments and postimpact strata. Graphite-rich cataclasite marks a detachment fault atop the lower basement-derived section. Overlying impactites consist mainly of basement-derived clasts and impact melt particles, and coastal-plain sediment clasts are underrepresented. Shocked quartz is common, and coesite and reidite are confirmed by Raman spectra. Silicate glasses have textures indicating immiscible melts at quench, and they are partly altered to smectite. Chrome spinel, baddeleyite, and corundum in silicate glass indicate high-temperature crystallization under silica undersaturation. Clast-rich impact melt rocks contain α-cristobalite and monoclinic tridymite. The impactites record an upward transition from slumped ground surge to melt-rich fallback from the ejecta plume. Basement-derived rocks include amphibolite-facies schists, greenschist(?)-facies quartz-feldspar gneiss blocks and subgreenschist-facies shale and siltstone clasts in polymict impact breccias, the amphibolite block, and the granite slab. The granite slab, underlying sand, and amphibolite block represent rock avalanches from inward collapse of unshocked bedrock around the transient crater rim. Gneissic and massive granites in the slab yield U-Pb sensitive high-resolution ion microprobe (SHRIMP) zircon dates of 615 ± 7 Ma and 254 ± 3 Ma, respectively. Postimpact heating was <~350 °C in the lower basement-derived section based on undisturbed 40Ar/39Ar plateau ages of muscovite and <~150 °C in sand above the suevite based on 40Ar/39Ar age spectra of detrital microcline.

  16. Amphiphilic copolymers based on polyoxazoline and grape seed vegetable oil derivatives: self-assemblies and dynamic light scattering

    NASA Astrophysics Data System (ADS)

    Travelet, Christophe; Stemmelen, Mylène; Lapinte, Vincent; Dubreuil, Frédéric; Robin, Jean-Jacques; Borsali, Redouane

    2013-06-01

    The self-assembly in solution of original structures of amphiphilic partially natural copolymers based on polyoxazoline [more precisely poly(2-methyl-2-oxazoline) (POx)] and grape seed vegetable oil derivatives (linear, T-, and trident-structure) is investigated. The results show that such systems are found, using dynamic light scattering (DLS), to spontaneously self-organize into monomodal, narrow-size, and stable nanoparticles in aqueous medium. The obtained hydrodynamic diameters ( D h) range from 8.6 to 32.5 nm. Specifically, such size increases strongly with increasing natural block (i.e., lipophilic species) length due to higher hydrophobic interactions (from 10.1 nm for C19 to 19.2 nm for C57). Furthermore, increasing the polyoxazoline (i.e., hydrophilic block) length leads to a moderate linear increase of the D h-values. Therefore, the first-order size effect comes from the natural lipophilic block, whereas the characteristic size can be tuned more finely (i.e., in a second-order) by choosing appropriately the polyoxazoline length. The DLS results in terms of characteristic size are corroborated using nanoparticle tracking analysis (NTA), and also by atomic force microscopy (AFM) and transmission electron microscopy (TEM) imaging where well-defined spherical and individual nanoparticles exhibit a very good mechanical resistance upon drying. Moreover, changing the lipophilic block architecture from linear to T-shape, while keeping the same molar mass, generates a branching and thus a shrinking by a factor of 2 of the nanoparticle volume, as observed by DLS. In this paper, it is clearly shown that the self-assemblies of amphiphilic block copolymer obtained from grape seed vegetable oil derivatives (sustainable renewable resources) as well as their tunability are of great interest for biomass valorization at the nanoscale level [continuation of the article by Stemmelen et al. (Polym Chem 4:1445-1458, 2013)].

  17. New Insights into Tectonics of the Saint Elias, Alaska, Region Based on Local Seismicity and Tomography

    NASA Astrophysics Data System (ADS)

    Ruppert, N. A.; Zabelina, I.; Freymueller, J. T.

    2013-12-01

    Saint Elias Mountains in southern Alaska are manifestation of ongoing tectonic processes that include collision of the Yakutat block with and subduction of the Yakutat block and Pacific plate under the North American plate. Interaction of these tectonic blocks and plates is complex and not well understood. In 2005 and 2006 a network of 22 broadband seismic sites was installed in the region as part of the SainT Elias TEctonics and Erosion Project (STEEP), a five-year multi-disciplinary study that addressed evolution of the highest coastal mountain range on Earth. High quality seismic data provides unique insights into earthquake occurrence and velocity structure of the region. Local earthquake data recorded between 2005 and 2010 became a foundation for detailed study of seismotectonic features and crustal velocities. The highest concentration of seismicity follows the Chugach-St.Elias fault, a major on land tectonic structure in the region. This fault is also delineated in tomographic images as a distinct contrast between lower velocities to the south and higher velocities to the north. The low-velocity region corresponds to the rapidly-uplifted and exhumed sediments on the south side of the range. Earthquake source parameters indicate high degree of compression and undertrusting processes along the coastal area, consistent with multiple thrust structures mapped from geological studies in the region. Tomographic inversion reveals velocity anomalies that correlate with sedimentary basins, volcanic features and subducting Yakutat block. We will present precise earthquake locations and source parameters recorded with the STEEP and regional seismic network along with the results of P- and S-wave tomographic inversion.

  18. Extrapunitive and Intropunitive Individuals Activate Different Parts of the Prefrontal Cortex under an Ego-Blocking Frustration

    PubMed Central

    Minamoto, Takehiro; Osaka, Mariko; Yaoi, Ken; Osaka, Naoyuki

    2014-01-01

    Different people make different responses when they face a frustrating situation: some punish others (extrapunitive), while others punish themselves (intropunitive). Few studies have investigated the neural structures that differentiate extrapunitive and intropunitive individuals. The present fMRI study explored these neural structures using two different frustrating situations: an ego-blocking situation which blocks a desire or goal, and a superego-blocking situation which blocks self-esteem. In the ego-blocking condition, the extrapunitive group (n = 9) showed greater activation in the bilateral ventrolateral prefrontal cortex, indicating that these individuals prefer emotional processing. On the other hand, the intropunitive group (n = 9) showed greater activation in the left dorsolateral prefrontal cortex, possibly reflecting an effortful control for anger reduction. Such patterns were not observed in the superego-blocking condition. These results indicate that the prefrontal cortex is the source of individual differences in aggression direction in the ego-blocking situation. PMID:24454951

  19. 5. "TEST STAND 13, CONCRETE STRUCTURAL SECTIONS AND DETAILS." Specifications ...

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

    5. "TEST STAND 1-3, CONCRETE STRUCTURAL SECTIONS AND DETAILS." Specifications No. OC12-50-10; Drawing No. 60-09-06; no sheet number within title block. D.O. SERIES 1109/17, Rev. A. Stamped: AS BUILT; NO CHANGES. Date of Revision A: 11/1/50. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-3, Test Area 1-115, northwest end of Saturn Boulevard, Boron, Kern County, CA

  20. Copolymerization of Glycolide and ɛ-Caprolactone Using 12-Aminolauric Acid Modified Montmorillonite

    NASA Astrophysics Data System (ADS)

    Gallos, HAV; Reyes, LQ

    2017-09-01

    Poly(glycolide-co-ɛ-caprolactone) (PGLYCL) nanocomposites were prepared by copolymerization glycolide (GLY) and ɛ-caprolactone (ɛ-CL) in the presence of varying loadings 12-aminolauric acid (12-ALA)-modified montmorillonite. Copolymerization was successfully achieved based on the increase in polymer molecular weight after the reaction determined by gel permeation chromatography (GPC). The amount of the poly(glycolide) block and poly(ɛ-caprolactone) block units in the copolymer, identified by proton nuclear magnetic resonance (1H-NMR) spectroscopy, suggested that the increase in organo-clay loading cause a reduction GLYL: ɛ-CLL ratio. The arrangement of the monomers in the polymer products was elucidated to have an ABA triblock structure, where PCL block is the central block and the PGLY is found at both end of the copolymer. The presence of intercalated and exfoliated silicates in the nanocomposites were observed by x-ray diffraction (XRD) analysis. The biocompatibility of the nanocomposites with NCTC 292 mouse normal fibroblast was high relative to untreated cell cultures using tetrazolium bromide (MTT)-dye reduction assay.

  1. The role of frictional contact of constituent blocks on the stability of masonry domes.

    PubMed

    Beatini, Valentina; Royer-Carfagni, Gianni; Tasora, Alessandro

    2018-01-01

    The observation of old construction works confirms that masonry domes can withstand tensile hoop stresses, at least up to a certain level. Here, such tensile resistance, rather than a priori assumed as a property of the bulk material, is attributed to the contact forces that are developed at the interfaces between interlocked blocks under normal pressure, specified by Coulomb's friction law. According to this rationale, the aspect ratio of the blocks, as well as the bond pattern, becomes of fundamental importance. To investigate the complex assembly of blocks, supposed rigid, we present a non-smooth contact dynamic analysis, implemented in a custom software based on the Project Chrono C++ framework and complemented with parametric-design interfaces for pre- and post-processing complex geometries. Through this advanced tool, we investigate the role of frictional forces resisting hoop stresses in the stability of domes, either circular or oval, under static and dynamic loading, focusing, in particular, on the structural role played by the underlying drum and the surmounting tiburium .

  2. Toward Generalization of Iterative Small Molecule Synthesis

    PubMed Central

    Lehmann, Jonathan W.; Blair, Daniel J.; Burke, Martin D.

    2018-01-01

    Small molecules have extensive untapped potential to benefit society, but access to this potential is too often restricted by limitations inherent to the customized approach currently used to synthesize this class of chemical matter. In contrast, the “building block approach”, i.e., generalized iterative assembly of interchangeable parts, has now proven to be a highly efficient and flexible way to construct things ranging all the way from skyscrapers to macromolecules to artificial intelligence algorithms. The structural redundancy found in many small molecules suggests that they possess a similar capacity for generalized building block-based construction. It is also encouraging that many customized iterative synthesis methods have been developed that improve access to specific classes of small molecules. There has also been substantial recent progress toward the iterative assembly of many different types of small molecules, including complex natural products, pharmaceuticals, biological probes, and materials, using common building blocks and coupling chemistry. Collectively, these advances suggest that a generalized building block approach for small molecule synthesis may be within reach. PMID:29696152

  3. Security of fragile authentication watermarks with localization

    NASA Astrophysics Data System (ADS)

    Fridrich, Jessica

    2002-04-01

    In this paper, we study the security of fragile image authentication watermarks that can localize tampered areas. We start by comparing the goals, capabilities, and advantages of image authentication based on watermarking and cryptography. Then we point out some common security problems of current fragile authentication watermarks with localization and classify attacks on authentication watermarks into five categories. By investigating the attacks and vulnerabilities of current schemes, we propose a variation of the Wong scheme18 that is fast, simple, cryptographically secure, and resistant to all known attacks, including the Holliman-Memon attack9. In the new scheme, a special symmetry structure in the logo is used to authenticate the block content, while the logo itself carries information about the block origin (block index, the image index or time stamp, author ID, etc.). Because the authentication of the content and its origin are separated, it is possible to easily identify swapped blocks between images and accurately detect cropped areas, while being able to accurately localize tampered pixels.

  4. Computations of Unsteady Viscous Compressible Flows Using Adaptive Mesh Refinement in Curvilinear Body-fitted Grid Systems

    NASA Technical Reports Server (NTRS)

    Steinthorsson, E.; Modiano, David; Colella, Phillip

    1994-01-01

    A methodology for accurate and efficient simulation of unsteady, compressible flows is presented. The cornerstones of the methodology are a special discretization of the Navier-Stokes equations on structured body-fitted grid systems and an efficient solution-adaptive mesh refinement technique for structured grids. The discretization employs an explicit multidimensional upwind scheme for the inviscid fluxes and an implicit treatment of the viscous terms. The mesh refinement technique is based on the AMR algorithm of Berger and Colella. In this approach, cells on each level of refinement are organized into a small number of topologically rectangular blocks, each containing several thousand cells. The small number of blocks leads to small overhead in managing data, while their size and regular topology means that a high degree of optimization can be achieved on computers with vector processors.

  5. Effects of two-step Mg doping in p-GaN on efficiency characteristics of InGaN blue light-emitting diodes without AlGaN electron-blocking layers

    NASA Astrophysics Data System (ADS)

    Ryu, Han-Youl; Lee, Jong-Moo

    2013-05-01

    A light-emitting diode (LED) structure containing p-type GaN layers with two-step Mg doping profiles is proposed to achieve high-efficiency performance in InGaN-based blue LEDs without any AlGaN electron-blocking-layer structures. Photoluminescence and electroluminescence (EL) measurement results show that, as the hole concentration in the p-GaN interlayer between active region and the p-GaN layer increases, defect-related nonradiative recombination increases, while the electron current leakage decreases. Under a certain hole-concentration condition in the p-GaN interlayer, the electron leakage and active region degradation are optimized so that high EL efficiency can be achieved. The measured efficiency characteristics are analyzed and interpreted using numerical simulations.

  6. Usage of digital image correlation in assessment of behavior of block element pavement structure

    NASA Astrophysics Data System (ADS)

    Grygierek, M.; Grzesik, B.; Rokitowski, P.; Rusin, T.

    2018-05-01

    In diagnostics of existing road pavement structures deflection measurements have fundamental meaning, because of ability to assess present stiffness (bearing capacity) of whole layered construction. During test loading the reaction of pavement structure to applied load is measured in central point or in a few points located along a straight on a 1.5 ÷ 1.8 m distance (i.e. Falling Weight Deflectometer) in similar spacing equal to 20 ÷ 30 cm. Typical measuring techniques are productive and precise enough for most common pavement structures such as flexible, semi-rigid and rigid. It should be noted that in experimental research as well as in pavements in complex stress state, measurement techniques allowing observation of pavement deformation in 3D would have been very helpful. A great example of that type of pavements is a block element pavement structure consisting of i.e. paving blocks or stone slabs. Due to high stiffness and confined ability of cooperation of surrounding block elements, in that type of pavements fatigue life is strongly connected with displacement distribution. Unfortunately, typical deflection measurement methods forefend displacement observations and rotation of single block elements like paving blocks or slabs. Another difficult problem is to carry out unmistakable analysis of cooperation between neighboring elements. For more precise observations of displacements state of block element pavements under a wheel load a Digital Image Correlation (DIC) was used. Application of this method for assessment of behavior of stone slabs pavement under a traffic load enabled the monitoring of deformations distribution and encouraged to formulate conclusions about the initiation mechanism and development of damages in this type of pavement structures. Results shown in this article were obtained in field tests executed on an exploited pavement structure with a surface course made of granite slabs with dimensions 0.5x1.0x0.14 m.

  7. Structural inhibition and reactivation of Escherichia coli septation by elements of the SOS and TER pathways

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

    Dopazo, A.; Tormo, A.; Aldea, M.

    1987-04-01

    The inhibition of cell division caused by induction of the SOS pathway in Escherichia coli structurally blocks septation, as deduced from two sets of results. Potential septation sites active at the time of SOS induction became inactivated, while those initiated during the following doubling time were active. Penicillin resistance increased in wild-type UV light-irradiated cells, a behavior similar to that observed in mutants in which structural blocks were introduced by inactivation of FtsA. Potential septation sites that have been structurally blocked by either the SOS division inhibitor, furazlocillin inhibition of PBP3, or inactivation of a TER pathway component, FtsA3, couldmore » be reactivated one doubling time after removal of the inhibitory agent in the presence of an active lon gene product. Reactivation of potential septation sites blocked by the presence of an inactivated FtsA3 was significantly lower when the lon protease was not active, suggesting that Lon plays a role in the removal of inactivated TER pathway products from the blocked potential septation sites.« less

  8. m1A and m1G Potently Disrupt A-RNA Structure Due to the Intrinsic Instability of Hoogsteen Base Pairs

    PubMed Central

    Zhou, Huiqing; Kimsey, Isaac J.; Nikolova, Evgenia N.; Sathyamoorthy, Bharathwaj; Grazioli, Gianmarc; McSally, James; Bai, Tianyu; Wunderlich, Christoph H.; Kreutz, Christoph; Andricioaei, Ioan; Al-Hashimi, Hashim M.

    2016-01-01

    The B-DNA double helix can dynamically accommodate G–C and A–T base pairs in either Watson-Crick or Hoogsteen configurations. Here, we show that G–C+ and A–U Hoogsteen base pairs are strongly disfavored in A-RNA. As a result, N1-methyl adenosine and N1-methyl guanosine, which occur in DNA as a form of alkylation damage, and in RNA as a posttranscriptional modification, have dramatically different consequences. They create G–C+ and A–U Hoogsteen base pairs in duplex DNA that maintain the structural integrity of the double helix, but block base pairing all together and induce local duplex melting in RNA, providing a mechanism for potently disrupting RNA structure through posttranscriptional modifications. The markedly different propensities to form Hoogsteen base pairs in B-DNA and A-RNA may help meet the opposing requirements of maintaining genome stability on one hand, and dynamically modulating the structure of the epitranscriptome on the other. PMID:27478929

  9. Crystal Structure of HIV-1 Primary Receptor CD4 i Complex with a Potent Antiviral Antibody

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

    Freeman, M.M.; Hong, X.; Seaman, M.S.

    2010-06-18

    Ibalizumab is a humanized, anti-CD4 monoclonal antibody. It potently blocks HIV-1 infection and targets an epitope in the second domain of CD4 without interfering with immune functions mediated by interaction of CD4 with major histocompatibility complex (MHC) class II molecules. We report here the crystal structure of ibalizumab Fab fragment in complex with the first two domains (D1-D2) of CD4 at 2.2 {angstrom} resolution. Ibalizumab grips CD4 primarily by the BC-loop (residues 121125) of D2, sitting on the opposite side of gp120 and MHC-II binding sites. No major conformational change in CD4 accompanies binding to ibalizumab. Both monovalent and bivalentmore » forms of ibalizumab effectively block viral infection, suggesting that it does not need to crosslink CD4 to exert antiviral activity. While gp120-induced structural rearrangements in CD4 are probably minimal, CD4 structural rigidity is dispensable for ibalizumab inhibition. These results could guide CD4-based immunogen design and lead to a better understanding of HIV-1 entry.« less

  10. Electromagnetic scattering of large structures in layered earths using integral equations

    NASA Astrophysics Data System (ADS)

    Xiong, Zonghou; Tripp, Alan C.

    1995-07-01

    An electromagnetic scattering algorithm for large conductivity structures in stratified media has been developed and is based on the method of system iteration and spatial symmetry reduction using volume electric integral equations. The method of system iteration divides a structure into many substructures and solves the resulting matrix equation using a block iterative method. The block submatrices usually need to be stored on disk in order to save computer core memory. However, this requires a large disk for large structures. If the body is discretized into equal-size cells it is possible to use the spatial symmetry relations of the Green's functions to regenerate the scattering impedance matrix in each iteration, thus avoiding expensive disk storage. Numerical tests show that the system iteration converges much faster than the conventional point-wise Gauss-Seidel iterative method. The numbers of cells do not significantly affect the rate of convergency. Thus the algorithm effectively reduces the solution of the scattering problem to an order of O(N2), instead of O(N3) as with direct solvers.

  11. Building blocks for automated elucidation of metabolites: machine learning methods for NMR prediction.

    PubMed

    Kuhn, Stefan; Egert, Björn; Neumann, Steffen; Steinbeck, Christoph

    2008-09-25

    Current efforts in Metabolomics, such as the Human Metabolome Project, collect structures of biological metabolites as well as data for their characterisation, such as spectra for identification of substances and measurements of their concentration. Still, only a fraction of existing metabolites and their spectral fingerprints are known. Computer-Assisted Structure Elucidation (CASE) of biological metabolites will be an important tool to leverage this lack of knowledge. Indispensable for CASE are modules to predict spectra for hypothetical structures. This paper evaluates different statistical and machine learning methods to perform predictions of proton NMR spectra based on data from our open database NMRShiftDB. A mean absolute error of 0.18 ppm was achieved for the prediction of proton NMR shifts ranging from 0 to 11 ppm. Random forest, J48 decision tree and support vector machines achieved similar overall errors. HOSE codes being a notably simple method achieved a comparatively good result of 0.17 ppm mean absolute error. NMR prediction methods applied in the course of this work delivered precise predictions which can serve as a building block for Computer-Assisted Structure Elucidation for biological metabolites.

  12. Chemical structure-guided design of dynapyrazoles, cell-permeable dynein inhibitors with a unique mode of action

    PubMed Central

    Steinman, Jonathan B; Santarossa, Cristina C; Miller, Rand M; Yu, Lola S; Serpinskaya, Anna S; Furukawa, Hideki; Morimoto, Sachie; Tanaka, Yuta; Nishitani, Mitsuyoshi; Asano, Moriteru; Zalyte, Ruta; Ondrus, Alison E; Johnson, Alex G; Ye, Fan; Nachury, Maxence V; Fukase, Yoshiyuki; Aso, Kazuyoshi; Foley, Michael A; Gelfand, Vladimir I; Chen, James K; Carter, Andrew P; Kapoor, Tarun M

    2017-01-01

    Cytoplasmic dyneins are motor proteins in the AAA+ superfamily that transport cellular cargos toward microtubule minus-ends. Recently, ciliobrevins were reported as selective cell-permeable inhibitors of cytoplasmic dyneins. As is often true for first-in-class inhibitors, the use of ciliobrevins has in part been limited by low potency. Moreover, suboptimal chemical properties, such as the potential to isomerize, have hindered efforts to improve ciliobrevins. Here, we characterized the structure of ciliobrevins and designed conformationally constrained isosteres. These studies identified dynapyrazoles, inhibitors more potent than ciliobrevins. At single-digit micromolar concentrations dynapyrazoles block intraflagellar transport in the cilium and lysosome motility in the cytoplasm, processes that depend on cytoplasmic dyneins. Further, we find that while ciliobrevins inhibit both dynein's microtubule-stimulated and basal ATPase activity, dynapyrazoles strongly block only microtubule-stimulated activity. Together, our studies suggest that chemical-structure-based analyses can lead to inhibitors with improved properties and distinct modes of inhibition. DOI: http://dx.doi.org/10.7554/eLife.25174.001 PMID:28524820

  13. Microwave spectroscopy of biomolecular building blocks.

    PubMed

    Alonso, José L; López, Juan C

    2015-01-01

    Microwave spectroscopy, considered as the most definitive gas phase structural probe, is able to distinguish between different conformational structures of a molecule, because they have unique spectroscopic constants and give rise to distinct individual rotational spectra.Previously, application of this technique was limited to molecular specimens possessing appreciable vapor pressures, thus discarding the possibility of studying many other molecules of biological importance, in particular those with high melting points, which had a tendency to undergo thermal reactions, and ultimately degradation, upon heating.Nowadays, the combination of laser ablation with Fourier transform microwave spectroscopy techniques, in supersonic jets, has enabled the gas-phase study of such systems. In this chapter, these techniques, including broadband spectroscopy, as well as results of their application into the study of the conformational panorama and structure of biomolecular building blocks, such as amino acids, nucleic bases, and monosaccharides, are briefly discussed, and with them, the tools for conformational assignation - rotational constants, nuclear quadrupole coupling interaction, and dipole moment.

  14. How to Switch Off a Histidine Kinase: Crystal Structure of Geobacillus Stearothermophilus KinB with the Inhibitor Sda

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

    Bick, M.; Lamour, V; Rajashankar, K

    2009-01-01

    Entry to sporulation in bacilli is governed by a histidine kinase phosphorelay, a variation of the predominant signal transduction mechanism in prokaryotes. Sda directly inhibits sporulation histidine kinases in response to DNA damage and replication defects. We determined a 2.0-Angstroms-resolution X-ray crystal structure of the intact cytoplasmic catalytic core [comprising the dimerization and histidine phosphotransfer domain (DHp domain), connected to the ATP binding catalytic domain] of the Geobacillus stearothermophilus sporulation kinase KinB complexed with Sda. Structural and biochemical analyses reveal that Sda binds to the base of the DHp domain and prevents molecular transactions with the DHp domain to whichmore » it is bound by acting as a simple molecular barricade. Sda acts to sterically block communication between the catalytic domain and the DHp domain, which is required for autophosphorylation, as well as to sterically block communication between the response regulator Spo0F and the DHp domain, which is required for phosphotransfer and phosphatase activities.« less

  15. Wrong-site nerve blocks: A systematic literature review to guide principles for prevention.

    PubMed

    Deutsch, Ellen S; Yonash, Robert A; Martin, Donald E; Atkins, Joshua H; Arnold, Theresa V; Hunt, Christina M

    2018-05-01

    Wrong-site nerve blocks (WSBs) are a significant, though rare, source of perioperative morbidity. WSBs constitute the most common type of perioperative wrong-site procedure reported to the Pennsylvania Patient Safety Authority. This systematic literature review aggregates information about the incidence, patient consequences, and conditions that contribute to WSBs, as well as evidence-based methods to prevent them. A systematic search of English-language publications was performed, using the PRISMA process. Seventy English-language publications were identified. Analysis of four publications reporting on at least 10,000 blocks provides a rate of 0.52 to 5.07 WSB per 10,000 blocks, unilateral blocks, or "at risk" procedures. The most commonly mentioned potential consequence was local anesthetic toxicity. The most commonly mentioned contributory factors were time pressure, personnel factors, and lack of site-mark visibility (including no site mark placed). Components of the block process that were addressed include preoperative nerve-block verification, nerve-block site marking, time-outs, and the healthcare facility's structure and culture of safety. A lack of uniform reporting criteria and divergence in the data and theories presented may reflect the variety of circumstances affecting when and how nerve blocks are performed, as well as the infrequency of a WSB. However, multiple authors suggest three procedural steps that may help to prevent WSBs: (1) verify the nerve-block procedure using multiple sources of information, including the patient; (2) identify the nerve-block site with a visible mark; and (3) perform time-outs immediately prior to injection or instillation of the anesthetic. Hospitals, ambulatory surgical centers, and anesthesiology practices should consider creating site-verification processes with clinician input and support to develop sustainable WSB-prevention practices. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Double hydrophilic block copolymer controlled growth and self-assembly of CaCO3 multilayered structures at the air/water interface.

    PubMed

    Gao, Yun-Xiang; Yu, Shu-Hong; Guo, Xiao-Hui

    2006-07-04

    Double hydrophilic block copolymers PEG-b-PEI-linear with different PEI block lengths have been examined for CaCO3 mineralization at the air/water interface. The results demonstrated that either PEI length or the solution acidity had a significant influence on the morphogenesis of vaterite crystals at the air/water interface. A possible mechanism for the stratification of CaCO3 vaterite crystals has been proposed. Increasing either PEI length or the initial pH value of the solution will decrease the density of the PEG block anchored on the binding interface and result in exposing more space as binding interface to solution and favoring the subnucleation and stratification growth on the polymer-CaCO3 interface. In contrast, higher density of PEG blocks will stabilize the growing crystals more efficiently and inhibit subnucleation on the polymer-CaCO3 interface, and thus prevent the formation of stratified structures. This study provides an example that it is possible to access morphogenesis of calcium carbonate structures by a combination of a block copolymer with the air/water interface.

  17. Role of solution structure in self-assembly of conjugated block copolymer thin films

    DOE PAGES

    Brady, Michael A.; Ku, Sung -Yu; Perez, Louis A.; ...

    2016-10-24

    Conjugated block copolymers provide a pathway to achieve thermally stable nanostructured thin films for organic solar cells. We characterized the structural evolution of poly(3-hexylthiophene)- block-poly(diketopyrrolopyrrole–terthiophene) (P3HT- b-DPPT-T) from solution to nanostructured thin films. Aggregation of the DPPT-T block of P3HT- b-DPPT-T was found in solution by small-angle X-ray scattering with the P3HT block remaining well-solvated. The nanostructure in thin films was determined using a combination of wide and small-angle X-ray scattering techniques as a function of processing conditions. The structure in solution controlled the initial nanostructure in spin-cast thin films, allowing subsequent thermal annealing processes to further improve the ordering.more » In contrast to the results for thin films, nanostructural ordering was not observed in the bulk samples by small-angle X-ray scattering. Finally, these results suggest the importance of controlling solvent induced aggregation in forming nanostructured thin films of conjugated block copolymers.« less

  18. Inverse design of bulk morphologies in block copolymers using particle swarm optimization

    NASA Astrophysics Data System (ADS)

    Khadilkar, Mihir; Delaney, Kris; Fredrickson, Glenn

    Multiblock polymers are a versatile platform for creating a large range of nanostructured materials with novel morphologies and properties. However, achieving desired structures or property combinations is difficult due to a vast design space comprised of parameters including monomer species, block sequence, block molecular weights and dispersity, copolymer architecture, and binary interaction parameters. Navigating through such vast design spaces to achieve an optimal formulation for a target structure or property set requires an efficient global optimization tool wrapped around a forward simulation technique such as self-consistent field theory (SCFT). We report on such an inverse design strategy utilizing particle swarm optimization (PSO) as the global optimizer and SCFT as the forward prediction engine. To avoid metastable states in forward prediction, we utilize pseudo-spectral variable cell SCFT initiated from a library of defect free seeds of known block copolymer morphologies. We demonstrate that our approach allows for robust identification of block copolymers and copolymer alloys that self-assemble into a targeted structure, optimizing parameters such as block fractions, blend fractions, and Flory chi parameters.

  19. Role of solution structure in self-assembly of conjugated block copolymer thin films

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

    Brady, Michael A.; Ku, Sung -Yu; Perez, Louis A.

    Conjugated block copolymers provide a pathway to achieve thermally stable nanostructured thin films for organic solar cells. We characterized the structural evolution of poly(3-hexylthiophene)- block-poly(diketopyrrolopyrrole–terthiophene) (P3HT- b-DPPT-T) from solution to nanostructured thin films. Aggregation of the DPPT-T block of P3HT- b-DPPT-T was found in solution by small-angle X-ray scattering with the P3HT block remaining well-solvated. The nanostructure in thin films was determined using a combination of wide and small-angle X-ray scattering techniques as a function of processing conditions. The structure in solution controlled the initial nanostructure in spin-cast thin films, allowing subsequent thermal annealing processes to further improve the ordering.more » In contrast to the results for thin films, nanostructural ordering was not observed in the bulk samples by small-angle X-ray scattering. Finally, these results suggest the importance of controlling solvent induced aggregation in forming nanostructured thin films of conjugated block copolymers.« less

  20. Feasibility evaluation of a neutron grating interferometer with an analyzer grating based on a structured scintillator.

    PubMed

    Kim, Youngju; Kim, Jongyul; Kim, Daeseung; Hussey, Daniel S; Lee, Seung Wook

    2018-03-01

    We introduce an analyzer grating based on a structured scintillator fabricated by a gadolinium oxysulfide powder filling method for a symmetric Talbot-Lau neutron grating interferometer. This is an alternative way to analyze the Talbot self-image of a grating interferometer without using an absorption grating to block neutrons. Since the structured scintillator analyzer grating itself generates the signal for neutron detection, we do not need an additional scintillator screen as an absorption analyzer grating. We have developed and tested an analyzer grating based on a structured scintillator in our symmetric Talbot-Lau neutron grating interferometer to produce high fidelity absorption, differential phase, and dark-field contrast images. The acquired images have been compared to results of a grating interferometer utilizing a typical absorption analyzer grating with two commercial scintillation screens. The analyzer grating based on the structured scintillator enhances interference fringe visibility and shows a great potential for economical fabrication, compact system design, and so on. We report the performance of the analyzer grating based on a structured scintillator and evaluate its feasibility for the neutron grating interferometer.

  1. Feasibility evaluation of a neutron grating interferometer with an analyzer grating based on a structured scintillator

    NASA Astrophysics Data System (ADS)

    Kim, Youngju; Kim, Jongyul; Kim, Daeseung; Hussey, Daniel. S.; Lee, Seung Wook

    2018-03-01

    We introduce an analyzer grating based on a structured scintillator fabricated by a gadolinium oxysulfide powder filling method for a symmetric Talbot-Lau neutron grating interferometer. This is an alternative way to analyze the Talbot self-image of a grating interferometer without using an absorption grating to block neutrons. Since the structured scintillator analyzer grating itself generates the signal for neutron detection, we do not need an additional scintillator screen as an absorption analyzer grating. We have developed and tested an analyzer grating based on a structured scintillator in our symmetric Talbot-Lau neutron grating interferometer to produce high fidelity absorption, differential phase, and dark-field contrast images. The acquired images have been compared to results of a grating interferometer utilizing a typical absorption analyzer grating with two commercial scintillation screens. The analyzer grating based on the structured scintillator enhances interference fringe visibility and shows a great potential for economical fabrication, compact system design, and so on. We report the performance of the analyzer grating based on a structured scintillator and evaluate its feasibility for the neutron grating interferometer.

  2. Understanding and controlling morphology formation in Langmuir-Blodgett block copolymer films using PS-P4VP and PS-P4VP/PDP.

    PubMed

    Perepichka, Iryna I; Lu, Qing; Badia, Antonella; Bazuin, C Geraldine

    2013-04-09

    This contribution offers a comprehensive understanding of the factors that govern the morphologies of Langmuir-Blodgett (LB) monolayers of amphiphilic diblock copolymers (BCs). This is achieved by a detailed investigation of a wide range of polystyrene-poly(4-vinyl pyridine) (PS-P4VP) block copolymers, in contrast to much more limited ranges in previous studies. Parameters that are varied include the block ratios (mainly for similar total molecular weights, occasionally other total molecular weights), the presence or not of 3-n-pentadecylphenol (PDP, usually equimolar with VP, with which it hydrogen bonds), the spreading solution concentration ("low" and "high"), and the LB technique (standard vs "solvent-assisted"). Our observations are compared with previously published results on other amphiphilic diblock copolymers, which had given rise to contradictory interpretations of morphology formation. Based on the accumulated results, we re-establish early literature conclusions that three main categories of LB block copolymer morphologies are obtained depending on the block ratio, termed planar, strand, and dot regimes. The block composition boundaries in terms of mol % block content are shown to be similar for all BCs having alkyl chain substituents on the hydrophilic block (such as PS-P4VP/PDP) and are shifted to higher values for BCs with no alkyl chain substituents (such as PS-P4VP). This is attributed to the higher surface area per repeat unit of the hydrophilic block monolayer on the water surface for the former, as supported by the onset and limiting areas of the Langmuir isotherms for the BCs in the dot regime. 2D phase diagrams are discussed in terms of relative effective surface areas of the two blocks. We identify and discuss how kinetic effects on morphology formation, which have been highlighted in more recent literature, are superposed on the compositional effects. The kinetic effects are shown to depend on the morphology regime, most strongly influencing the strand and, especially, planar regimes, where they give rise to a diversity of specific structures. Besides film dewetting mechanisms, which are different when occurring in structured versus unstructured films (the latter previously discussed in the literature), kinetic influences are discussed in terms of chain association dynamics leading to depletion effects that impact on growing aggregates. These depletion effects particularly manifest themselves in more dilute spreading solutions, with higher molecular weight polymers, and in composition regimes characterized by equilibrium degrees of aggregation that are effectively infinite. It is by understanding these various kinetic influences that the diversity of structures can be classified by the three main composition-dependent regimes.

  3. Petrographic and chemical reconnaissance study of some granitic and gneissic rocks near the San Andreas fault from Bodega Head to Cajon Pass, California

    USGS Publications Warehouse

    Ross, Donald C.

    1972-01-01

    This petrographic and chemical study is based on reconnaissance sampling of granitic and related gneissic rock in the California Coast and Transverse Ranges. In the Coast Ranges, granitic rocks are restricted to an elongate belt, the Salinian block, between the San Andreas and Sur-Nacimiento fault zones. These rocks have a considerable compositional range, but are dominantly quartz monzonite and granodiorite. Moist of the Salinian block seems to be a structurally coherent basement block of chemically related granitic rocks. However, on both the east and the west sides of the block, gneiss crops out in abundance; these rocks may be structurally separate from the main part of the Salinian block. In the Transverse Ranges, the granitic and related rocks are dominantly of granodiorite composition, and in many areas granitic and gneissic rocks are intimately intermixed.Chemically the rocks of the California Coast and Transverse Ranges are somewhat intermediate in character between those of the east-central part of the Sierra Nevada batholith and those of the western part of the Sierra Nevada batholith and the southern California batholith. Probably the closest similarity is to the east-central Sierra Nevada rocks, but the rocks of the Coast and Transverse Ranges are somewhat higher in Al2O3 and lower in K2O than Sierran rocks of the comparable SiO2 content.Granitic basement rocks of the Salinian block are now anomalously sandwiched between Franciscan terranes. The petrographic and chemical data are compatible with the concept that the Salinian rocks were originally part of the great batholithic belt along the west coast, which is exemplified by the Sierra Nevada hatholith. It also seems most likely that the Salinian block was transported from somewhere south of the Sierra Nevada batholith by large-scale right-lateral movement along the San Andreas fault zone.

  4. Reliability and validity of the faculty evaluation instrument used at King Saud bin Abdulaziz University for Health Sciences: Results from the Haematology Course.

    PubMed

    Al-Eidan, Fahad; Baig, Lubna Ansari; Magzoub, Mohi-Eldin; Omair, Aamir

    2016-04-01

    To assess reliability and validity of evaluation tool using Haematology course as an example. The cross-sectional study was conducted at King Saud Bin Abdul Aziz University of Health Sciences, Riyadh, Saudi Arabia, in 2012, while data analysis was completed in 2013. The 27-item block evaluation instrument was developed by a multidisciplinary faculty after a comprehensive literature review. Validity of the questionnaire was confirmed using principal component analysis with varimax rotation and Kaiser normalisation. Identified factors were combined to get the internal consistency reliability of each factor. Student's t-test was used to compare mean ratings between male and female students for the faculty and block evaluation. Of the 116 subjects in the study, 80(69%) were males and 36(31%) were females. Reliability of the questionnaire was Cronbach's alpha 0.91. Factor analysis yielded a logically coherent 7 factor solution that explained 75% of the variation in the data. The factors were group dynamics in problem-based learning (alpha0.92), block administration (alpha 0.89), quality of objective structured clinical examination (alpha 0.86), block coordination (alpha 0.81), structure of problem-based learning (alpha 0.84), quality of written exam (alpha 0.91), and difficulty of exams (alpha0.41). Female students' opinion on depth of analysis and critical thinking was significantly higher than that of the males (p=0.03). The faculty evaluation tool used was found to be reliable, but its validity, as assessed through factor analysis, has to be interpreted with caution as the responders were less than the minimum required for factor analysis.

  5. Geologic columns for the ICDP-USGS Eyreville A and B cores, Chesapeake Bay impact structure: Sediment-clast breccias, 1096 to 444 m depth

    USGS Publications Warehouse

    Edwards, L.E.; Powars, D.S.; Gohn, G.S.; Dypvik, H.

    2009-01-01

    The Eyreville A and B cores, recovered from the "moat" of the Chesapeake Bay impact structure, provide a thick section of sediment-clast breccias and minor stratified sediments from 1095.74 to 443.90 m. This paper discusses the components of these breccias, presents a geologic column and descriptive lithologic framework for them, and formalizes the Exmore Formation. From 1095.74 to ??867 m, the cores consist of nonmarine sediment boulders and sand (rare blocks up to 15.3 m intersected diameter). A sharp contact in both cores at ??867 m marks the lowest clayey, silty, glauconitic quartz sand that constitutes the base of the Exmore Formation and its lower diamicton member. Here, material derived from the upper sediment target layers, as well as some impact ejecta, occurs. The block-dominated member of the Exmore Formation, from ??855-618.23 m, consists of nonmarine sediment blocks and boulders (up to 45.5 m) that are juxtaposed complexly. Blocks of oxidized clay are an important component. Above 618.23 m, which is the base of the informal upper diamicton member of the Exmore Formation, the glauconitic matrix is a consistent component in diamicton layers between nonmarine sediment clasts that decrease in size upward in the section. Crystalline-rock clasts are not randomly distributed but rather form local concentrations. The upper part of the Exmore Formation consists of crudely fining-upward sandy packages capped by laminated silt and clay. The overlap interval of Eyreville A and B (940-??760 m) allows recognition of local similarities and differences in the breccias. ?? 2009 The Geological Society of America.

  6. Influence of different TiO2 blocking films on the photovoltaic performance of perovskite solar cells

    NASA Astrophysics Data System (ADS)

    Zhang, Chenxi; Luo, Yudan; Chen, Xiaohong; Ou-Yang, Wei; Chen, Yiwei; Sun, Zhuo; Huang, Sumei

    2016-12-01

    Organolead trihalide perovskite materials have been successfully used as light absorbers in efficient photovoltaic (PV) cells. Cell structures based on mesoscopic metal oxides and planar heterojunctions have already demonstrated very impressive and brisk advances, holding great potential to grow into a mature PV technology. High power conversion efficiency (PCE) values have been obtained from the mesoscopic configuration in which a few hundred nano-meter thick mesoporous scaffold (e.g. TiO2 or Al2O3) infiltrated by perovskite absorber was sandwiched between the electron and hole transport layers. A uniform and compact hole-blocking layer is necessary for high efficient perovskite-based thin film solar cells. In this study, we investigated the characteristics of TiO2 compact layer using various methods and its effects on the PV performance of perovskite solar cells. TiO2 compact layer was prepared by a sol-gel method based on titanium isopropoxide and HCl, spin-coating of titanium diisopropoxide bis (acetylacetonate), screen-printing of Dyesol's bocking layer titania paste, and a chemical bath deposition (CBD) technique via hydrolysis of TiCl4, respectively. The morphological and micro-structural properties of the formed compact TiO2 layers were characterized by scanning electronic microscopy and X-ray diffraction. The analyses of devices performance characteristics showed that surface morphologies of TiO2 compact films played a critical role in affecting the efficiencies. The nanocrystalline TiO2 film deposited via the CBD route acts as the most efficient hole-blocking layer and achieves the best performance in perovskite solar cells. The CBD-based TiO2 compact and dense layer offers a small series resistance and a large recombination resistance inside the device, and makes it possible to achieve a high power conversion efficiency of 12.80%.

  7. An FPGA-Based Silicon Neuronal Network with Selectable Excitability Silicon Neurons

    PubMed Central

    Li, Jing; Katori, Yuichi; Kohno, Takashi

    2012-01-01

    This paper presents a digital silicon neuronal network which simulates the nerve system in creatures and has the ability to execute intelligent tasks, such as associative memory. Two essential elements, the mathematical-structure-based digital spiking silicon neuron (DSSN) and the transmitter release based silicon synapse, allow us to tune the excitability of silicon neurons and are computationally efficient for hardware implementation. We adopt mixed pipeline and parallel structure and shift operations to design a sufficient large and complex network without excessive hardware resource cost. The network with 256 full-connected neurons is built on a Digilent Atlys board equipped with a Xilinx Spartan-6 LX45 FPGA. Besides, a memory control block and USB control block are designed to accomplish the task of data communication between the network and the host PC. This paper also describes the mechanism of associative memory performed in the silicon neuronal network. The network is capable of retrieving stored patterns if the inputs contain enough information of them. The retrieving probability increases with the similarity between the input and the stored pattern increasing. Synchronization of neurons is observed when the successful stored pattern retrieval occurs. PMID:23269911

  8. Significant structural reinterpretation of the giant October Field, Gulf of Suez, Egypt using SCAT, isogon based sections and 3D seismic

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

    Sercombe, W.J.; Smith, G.W.; Morse, J.D.

    1996-01-01

    The October field, a sub-salt giant in the extensional Gulf of Suez (Egypt) has been structurally reinterpreted for new reserve opportunities. Quantitative SCAT analyses of the wellbore dip data have been integrated with 3D seismic by using dip isogons to construct local structural sections. SCAT dip analysis was critical to the reinterpretation because SCAT revealed important structural information that previously was unresolvable using conventional tadpole plots. In gross aspect, the October Field is a homocline that trends NW-SE, dips to the NE, and is closed on the SW (updip) by the major Clysmic Normal Fault. SCAT accurately calculated the overallmore » trend of the field, but also identified important structural anomalies near the Clysmic fault and in the northwest and southeast plunge ends. In the northwest plunge end, SCAT has identified new, south dipping blocks that are transitional to the structurally-higher North October field. The southeast plunge end has been reinterpreted with correct azimuthal trends and new fault-block prospects. These new SCAT results have successfully improved the 3D seismic interpretation by providing a foundation of accurate in-situ structural control in an area of poor-to-fair seismic quality below the Miocene salt package.« less

  9. Significant structural reinterpretation of the giant October Field, Gulf of Suez, Egypt using SCAT, isogon based sections and 3D seismic

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

    Sercombe, W.J.; Smith, G.W.; Morse, J.D.

    1996-12-31

    The October field, a sub-salt giant in the extensional Gulf of Suez (Egypt) has been structurally reinterpreted for new reserve opportunities. Quantitative SCAT analyses of the wellbore dip data have been integrated with 3D seismic by using dip isogons to construct local structural sections. SCAT dip analysis was critical to the reinterpretation because SCAT revealed important structural information that previously was unresolvable using conventional tadpole plots. In gross aspect, the October Field is a homocline that trends NW-SE, dips to the NE, and is closed on the SW (updip) by the major Clysmic Normal Fault. SCAT accurately calculated the overallmore » trend of the field, but also identified important structural anomalies near the Clysmic fault and in the northwest and southeast plunge ends. In the northwest plunge end, SCAT has identified new, south dipping blocks that are transitional to the structurally-higher North October field. The southeast plunge end has been reinterpreted with correct azimuthal trends and new fault-block prospects. These new SCAT results have successfully improved the 3D seismic interpretation by providing a foundation of accurate in-situ structural control in an area of poor-to-fair seismic quality below the Miocene salt package.« less

  10. General synthesis of inorganic single-walled nanotubes

    PubMed Central

    Ni, Bing; Liu, Huiling; Wang, Peng-peng; He, Jie; Wang, Xun

    2015-01-01

    The single-walled nanotube (SWNT) is an interesting nanostructure for fundamental research and potential applications. However, very few inorganic SWNTs are available to date due to the lack of efficient fabrication methods. Here we synthesize four types of SWNT: sulfide; hydroxide; phosphate; and polyoxometalate. Each type of SWNT possesses essentially uniform diameters. Detailed studies illustrate that the formation of SWNTs is initiated by the self-coiling of the corresponding ultrathin nanostructure embryo/building blocks on the base of weak interactions between them, which is not limited to specific compounds or crystal structures. The interactions between building blocks can be modulated by varying the solvents used, thus multi-walled tubes can also be obtained. Our results reveal that the generalized synthesis of inorganic SWNTs can be achieved by the self-coiling of ultrathin building blocks under the proper weak interactions. PMID:26510862

  11. DNA bases thymine and adenine in bio-organic light emitting diodes.

    PubMed

    Gomez, Eliot F; Venkatraman, Vishak; Grote, James G; Steckl, Andrew J

    2014-11-24

    We report on the use of nucleic acid bases (NBs) in organic light emitting diodes (OLEDs). NBs are small molecules that are the basic building blocks of the larger DNA polymer. NBs readily thermally evaporate and integrate well into the vacuum deposited OLED fabrication. Adenine (A) and thymine (T) were deposited as electron-blocking/hole-transport layers (EBL/HTL) that resulted in increases in performance over the reference OLED containing the standard EBL material NPB. A-based OLEDs reached a peak current efficiency and luminance performance of 48 cd/A and 93,000 cd/m(2), respectively, while T-based OLEDs had a maximum of 76 cd/A and 132,000 cd/m(2). By comparison, the reference OLED yielded 37 cd/A and 113,000 cd/m(2). The enhanced performance of T-based devices is attributed to a combination of energy levels and structured surface morphology that causes more efficient and controlled hole current transport to the emitting layer.

  12. Application of blocking diagnosis methods to General Circulation Models. Part I: a novel detection scheme

    NASA Astrophysics Data System (ADS)

    Barriopedro, D.; García-Herrera, R.; Trigo, R. M.

    2010-12-01

    This paper aims to provide a new blocking definition with applicability to observations and model simulations. An updated review of previous blocking detection indices is provided and some of their implications and caveats discussed. A novel blocking index is proposed by reconciling two traditional approaches based on anomaly and absolute flows. Blocks are considered from a complementary perspective as a signature in the anomalous height field capable of reversing the meridional jet-based height gradient in the total flow. The method succeeds in identifying 2-D persistent anomalies associated to a weather regime in the total flow with blockage of the westerlies. The new index accounts for the duration, intensity, extension, propagation, and spatial structure of a blocking event. In spite of its increased complexity, the detection efficiency of the method is improved without hampering the computational time. Furthermore, some misleading identification problems and artificial assumptions resulting from previous single blocking indices are avoided with the new approach. The characteristics of blocking for 40 years of reanalysis (1950-1989) over the Northern Hemisphere are described from the perspective of the new definition and compared to those resulting from two standard blocking indices and different critical thresholds. As compared to single approaches, the novel index shows a better agreement with reported proxies of blocking activity, namely climatological regions of simultaneous wave amplification and maximum band-pass filtered height standard deviation. An additional asset of the method is its adaptability to different data sets. As critical thresholds are specific of the data set employed, the method is useful for observations and model simulations of different resolutions, temporal lengths and time variant basic states, optimizing its value as a tool for model validation. Special attention has been paid on the devise of an objective scheme easily applicable to General Circulation Models where observational thresholds may be unsuitable due to the presence of model bias. Part II of this study deals with a specific implementation of this novel method to simulations of the ECHO-G global climate model.

  13. The Impact of Individual Differences, Types of Model and Social Settings on Block Building Performance among Chinese Preschoolers.

    PubMed

    Tian, Mi; Deng, Zhu; Meng, Zhaokun; Li, Rui; Zhang, Zhiyi; Qi, Wenhui; Wang, Rui; Yin, Tingting; Ji, Menghui

    2018-01-01

    Children's block building performances are used as indicators of other abilities in multiple domains. In the current study, we examined individual differences, types of model and social settings as influences on children's block building performance. Chinese preschoolers ( N = 180) participated in a block building activity in a natural setting, and performance was assessed with multiple measures in order to identify a range of specific skills. Using scores generated across these measures, three dependent variables were analyzed: block building skills, structural balance and structural features. An overall MANOVA showed that there were significant main effects of gender and grade level across most measures. Types of model showed no significant effect in children's block building. There was a significant main effect of social settings on structural features, with the best performance in the 5-member group, followed by individual and then the 10-member block building. These findings suggest that boys performed better than girls in block building activity. Block building performance increased significantly from 1st to 2nd year of preschool, but not from second to third. The preschoolers created more representational constructions when presented with a model made of wooden rather than with a picture. There was partial evidence that children performed better when working with peers in a small group than when working alone or working in a large group. It is suggested that future study should examine other modalities rather than the visual one, diversify the samples and adopt a longitudinal investigation.

  14. Post-Metamorphic Thermal Anomaly across the Nacimiento Block, Central California: a Hydrothermal Overprint?

    NASA Astrophysics Data System (ADS)

    Lacroix, B.; Hughes, J.; Lahfid, A.; Delchini, S.

    2017-12-01

    The thermal history of the Nacimiento block located within the Franciscan Complex (California, USA) has been previously proposed based on both vitrinite reflectance (Rm) and illite cristallinity methods (Underwood et al., 1995). These authors suggest that the Nacimiento block is locally perturbed by a thermal anomaly (up to 300ºC), probably caused by post-metamorphic hydrothermal activity linked to the emplacement of an Au-deposit: the Los Burros Gold deposit. Although both thermal anomaly and deposit seem spatially correlated, their relationship is still poorly constrained. Detailed geological and structural mapping within the Los Burros Mining District (LBMD) coupled with a thermal study was conducted to better understand processes responsible for the anomalous temperatures recorded near the deposit. The regional maximum temperature reached by metasediments from the Nacimiento block have been first investigated using the Raman Spectroscopy of Carbonaceous Materials (RSCM) method. In addition, through careful fluid-inclusion and stable isotopes (O and C) studies on the deposit, the temperature and the potential source of the fluid responsible for the Los Burros Au-deposit emplacement were investigated. RSCM technique confirms the presence of a thermal anomaly in the range 260-320ºC near LBMD. However, our structural and petrographic results suggest that the thermal anomaly is not correlated to a post-metamorphic hydrothermal overprint but rather to a late, transpressive deformation uplifting buried metamorphic rocks.

  15. Two binuclear cyanide-bridged Cr(III)-Mn(III) complexes based-on [Cr(2,2'-bipy)(CN)4]- building block: synthesis, crystal structures and magnetic properties.

    PubMed

    Zhanga, Daopeng; Kong, Lingqian; Zhang, Hongyan

    2015-01-01

    Tetracyanide building block [Cr(2,2'-bipy)(CN)(4)]- and two bicompartimental Schiff-base based manganese(III) compounds have been employed to assemble cyanide-bridged heterometallic complexes, resulting in two cyanide-bridged CrIII-MnIII complexes: [Mn(L(1))(H(2)O)][Cr(2,2'-bipy)(CN)(4)]·CH(3)OH·2.5H(2)O (1) and [Mn(L(2))(H(2)O)][Cr(2,2'-bipy)(CN)(4)]·CH(3)OH·(3)H(2)O (2) (L1 = N,N'-(1,3-propylene)-bis(3-methoxysalicylideneiminate), L2 = N,N'-ethylene-bis(3-ethoxysalicylideneiminate)). Single X-ray diffraction analysis shows their similar cyanide-bridged binuclear structures, in which the cyanide precursor acting as monodentate ligand connects the manganese(III) ion. The binuclear complexes are self-complementary through coordinated aqua ligand and the free O4 compartment from the neighboring complex, giving H-bond linking dimer structure. Investigation over magnetic properties reveals the antiferromagnetic magnetic coupling between the cyanide-bridged Cr(III) and Mn(III) ions. A best-fit to the magnetic susceptibilities of these two complexes leads to the magnetic coupling constants J = -5.95 cm(-1), j = -0.61 cm(-1) (1) and J = -4.15 cm(-1), j = -0.57 cm(-1) (2), respectively.

  16. Sub-seismic scale folding and thrusting within an exposed mass transport deposit: A case study from NW Argentina

    NASA Astrophysics Data System (ADS)

    Sobiesiak, Matheus S.; Alsop, G. Ian; Kneller, Ben; Milana, Juan Pablo

    2017-03-01

    While imaging of mass transport deposits (MTDs) by seismic reflection techniques commonly reveals thrusts and large blocks that affect entire deposits, associated systems of folds are generally less apparent as they are typically below the limits of seismic resolution. However, such sub-seismic scale structures are important as they permit the direction of emplacement, gross kinematics and internal strain within MTDs to be determined. Here we present a rigorous description of two outcrop-scale MTDs exposed in La Peña gorge, northwestern Argentina. These Carboniferous MTDs enable us to illustrate structural changes from a compressional domain, marked by sets of imbricated sandstone layers, into an extensional domain, characterized by sheared blocks of sandstone embedded in a finer matrix. Folds may be progressively modified during slump translation, resulting in asymmetric folds, which undergo subsequent deformation leading to sheared fold limbs together with detached and rotated fold hinges. In order to constrain transport directions within the MTDs, we measured fold hinges, mud clast alignment, and thrust planes as kinematic indicators. We propose emplacement models for both MTDs based on the overall deformational behaviour of sandstone beds during translation. The first model is based on the internal geometries and structures of a fault-dominated MTD, and the second model is based on layer-normal shearing in a fold-dominated MTD.

  17. Cleave and couple: toward fully sustainable catalytic conversion of lignocellulose to value added building blocks and fuels.

    PubMed

    Sun, Zhuohua; Barta, Katalin

    2018-06-21

    The structural complexity of lignocellulose offers unique opportunities for the development of entirely new, energy efficient and waste-free pathways in order to obtain valuable bio-based building blocks. Such sustainable catalytic methods - specifically tailored to address the efficient conversion of abundant renewable starting materials - are necessary to successfully compete, in the future, with fossil-based multi-step processes. In this contribution we give a summary of recent developments in this field and describe our "cleave and couple" strategy, where "cleave" refers to the catalytic deconstruction of lignocellulose to aromatic and aliphatic alcohol intermediates, and "couple" involves the development of novel, sustainable transformations for the formation of C-C and C-N bonds in order to obtain a range of attractive products from lignocellulose.

  18. Structural Analysis via Generalized Interactive Graphics - STAGING. Volume III. System Manual.

    DTIC Science & Technology

    1979-09-01

    DISTRIBUTION UNLIMITED 17 DISTRIBUTION ST ATEMENT (of the abnsrct entered in Block 20. it different from, Report) IS SJPPLEMENTARY NOTES I9 KEY WORDS ILCI-lue on...prefixMENUDRIVER and the menu data base itself is cataloged as prefixMENU. The maintanance of the STAGING Material Property Data Base (MPDB...Property Data Base System, and conversion routines as describe,: -n Section 1.2 through 1.6. If any difficulties arise due to differences in operatire

  19. Crustal block structure by GPS data using neural network in the Northern Tien Shan

    NASA Astrophysics Data System (ADS)

    Kostuk, A.; Carmenate, D.

    2010-05-01

    For over ten years regular GPS measurements have been carried out by Research Station RAS in the Central Asia. The results of these measurements have not only proved the conclusion that the Earth's crust meridional compression equals in total about 17 mm/year from the Tarim massif to the Kazakh shield, but have also allowed estimating deformation behavior in the region. As is known, deformation behavior of continental crust is an actively discussed issue. On the one hand, the Earth's crust is presented as a set of microplates (blocks) and deformation here is a result of shifting along the blocks boundaries, on the other hand, lithospheric deformation is distributed by volume and meets the rheological model of nonlinear viscous fluid. This work represents an attempt to detect the block structure of the surface of the Northern Tien Shan using GPS velocity fields. As a significant difference from analogous works, appears the vector field clustering with the help of neural network used as a classifier by many criteria that allows dividing input space into areas and using of all three components of GPS velocity. In this case, we use such a feature of neural networks as self-organization. Among the mechanisms of self-organization there are two main classes: self-organization based on the Hebb associative rule and the mechanism of neuronal competition based on the generalized Kohonen rule. In this case, we use an approach of self-organizing networks in which we take neuronal competition as an algorithm for their training. As a rule, these are single-layer networks where each neuron is connected to all components of m-dimensional input vector. GPS vectors of the Central Asian velocity field located within the territory of the Northern Tien Shan were used as input patterns. Measurements at GPS sites were fulfilled in 36 hour-long sessions by double-frequency receivers Trimble and Topcon. In so doing, measurement discreteness equaled 30 seconds; the data were processed by GAMITGLOBK programs. An overall period of measurements lasted from 1995 to 2005. Those GPS vectors were admitted to processing that had an estimated error no more than 1 mm per year for each of the three components. In general, an obtained cluster structure reflecting the block structure of the Earth's crust of the Northern Tien Shan is proved by the location of active faults. Certainly, the structure analysis of GPS velocity field is a rather complicated task that yet does not have a definite solution; however, obtained results indicate the possibility of using of neural networks for solving such a problem.

  20. Genetic characterization of Russian honey bee stock selected for improved resistance to Varroa destructor.

    PubMed

    Bourgeois, A Lelania; Rinderer, Thomas E

    2009-06-01

    Maintenance of genetic diversity among breeding lines is important in selective breeding and stock management. The Russian Honey Bee Breeding Program has strived to maintain high levels of heterozygosity among its breeding lines since its inception in 1997. After numerous rounds of selection for resistance to tracheal and varroa mites and improved honey production, 18 lines were selected as the core of the program. These lines were grouped into three breeding blocks that were crossbred to improve overall heterozygosity levels of the population. Microsatellite DNA data demonstrated that the program has been successful. Heterozygosity and allelic richness values are high and there are no indications of inbreeding among the three blocks. There were significant levels of genetic structure measured among the three blocks. Block C was genetically distinct from both blocks A and B (F(ST) = 0.0238), whereas blocks A and B did not differ from each other (F(ST) = 0.0074). The same pattern was seen for genic (based on numbers of alleles) differentiation. Genetic distance, as measured by chord distance, indicates that all of the 18 lines are equally distant, with minimal clustering. The data indicate that the overall design of the breeding program has been successful in maintaining high levels of diversity and avoiding problems associated with inbreeding.

  1. Shaping Crystal-Crystal Phase Transitions

    NASA Astrophysics Data System (ADS)

    Du, Xiyu; van Anders, Greg; Dshemuchadse, Julia; Glotzer, Sharon

    Previous computational and experimental studies have shown self-assembled structure depends strongly on building block shape. New synthesis techniques have led to building blocks with reconfigurable shape and it has been demonstrated that building block reconfiguration can induce bulk structural reconfiguration. However, we do not understand systematically how this transition happens as a function of building block shape. Using a recently developed ``digital alchemy'' framework, we study the thermodynamics of shape-driven crystal-crystal transitions. We find examples of shape-driven bulk reconfiguration that are accompanied by first-order phase transitions, and bulk reconfiguration that occurs without any thermodynamic phase transition. Our results suggest that for well-chosen shapes and structures, there exist facile means of bulk reconfiguration, and that shape-driven bulk reconfiguration provides a viable mechanism for developing functional materials.

  2. REACTOR MODERATOR STRUCTURE

    DOEpatents

    Fraas, A.P.; Tudor, J.J.

    1963-08-01

    An improved moderator structure for nuclear reactors consists of moderator blocks arranged in horizontal layers to form a multiplicity of vertically stacked columns of blocks. The blocks in each vertical column are keyed together, and a ceramic grid is disposed between each horizontal layer of blocks. Pressure plates cover- the lateral surface of the moderator structure in abutting relationship with the peripheral terminal lengths of the ceramic grids. Tubular springs are disposed between the pressure plates and a rigid external support. The tubular springs have their axes vertically disposed to facilitate passage of coolant gas through the springs and are spaced apart a selected distance such that at sonae preselected point of spring deflection, the sides of the springs will contact adjacent springs thereby causing a large increase in resistance to further spring deflection. (AEC)

  3. Aquaporin-Based Biomimetic Polymeric Membranes: Approaches and Challenges

    PubMed Central

    Habel, Joachim; Hansen, Michael; Kynde, Søren; Larsen, Nanna; Midtgaard, Søren Roi; Jensen, Grethe Vestergaard; Bomholt, Julie; Ogbonna, Anayo; Almdal, Kristoffer; Schulz, Alexander; Hélix-Nielsen, Claus

    2015-01-01

    In recent years, aquaporin biomimetic membranes (ABMs) for water separation have gained considerable interest. Although the first ABMs are commercially available, there are still many challenges associated with further ABM development. Here, we discuss the interplay of the main components of ABMs: aquaporin proteins (AQPs), block copolymers for AQP reconstitution, and polymer-based supporting structures. First, we briefly cover challenges and review recent developments in understanding the interplay between AQP and block copolymers. Second, we review some experimental characterization methods for investigating AQP incorporation including freeze-fracture transmission electron microscopy, fluorescence correlation spectroscopy, stopped-flow light scattering, and small-angle X-ray scattering. Third, we focus on recent efforts in embedding reconstituted AQPs in membrane designs that are based on conventional thin film interfacial polymerization techniques. Finally, we describe some new developments in interfacial polymerization using polyhedral oligomeric silsesquioxane cages for increasing the physical and chemical durability of thin film composite membranes. PMID:26264033

  4. Weighted Discriminative Dictionary Learning based on Low-rank Representation

    NASA Astrophysics Data System (ADS)

    Chang, Heyou; Zheng, Hao

    2017-01-01

    Low-rank representation has been widely used in the field of pattern classification, especially when both training and testing images are corrupted with large noise. Dictionary plays an important role in low-rank representation. With respect to the semantic dictionary, the optimal representation matrix should be block-diagonal. However, traditional low-rank representation based dictionary learning methods cannot effectively exploit the discriminative information between data and dictionary. To address this problem, this paper proposed weighted discriminative dictionary learning based on low-rank representation, where a weighted representation regularization term is constructed. The regularization associates label information of both training samples and dictionary atoms, and encourages to generate a discriminative representation with class-wise block-diagonal structure, which can further improve the classification performance where both training and testing images are corrupted with large noise. Experimental results demonstrate advantages of the proposed method over the state-of-the-art methods.

  5. Remote Stabilization of Copper Paddlewheel Based Molecular Building Blocks in Metal-Organic Frameworks

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

    Gao, Wen-Yang; Cai, Rong; Pham, Tony

    Copper paddlewheel based molecular building blocks (MBBs) are ubiquitous and have been widely employed for the construction of highly porous metal–organic frameworks (MOFs). However, most copper paddlewheel based MOFs fail to retain their structural integrity in the presence of water. This instability is directly correlated to the plausible displacement of coordinating carboxylates in the copper paddlewheel MBB, [Cu₂(O₂C-)₄], by the strongly coordinating water molecules. In this comprehensive study, we illustrate the chemical stability control in the rht-MOF platform via strengthening the coordinating bonds within the triangular inorganic MBB, [Cu₃O(N 4–x(CH) xC-)₃] (x = 0, 1, or 2). Remotely, the chemicalmore » stabilization propagated into the paddlewheel MBB to afford isoreticular rht-MOFs with remarkably enhanced water/chemical stabilities compared to the prototypal rht-MOF-1.« less

  6. The Neoproterozoic-Paleozoic Arctic Margins: early stages of geodynamic evolution and plate reconstructions

    NASA Astrophysics Data System (ADS)

    Vernikovsky, V. A.; Metelkin, D. V.; Vernikovskaya, A. E.; Matushkin, N. Yu.; Lobkovsky, L. I.; Shipilov, E. V.

    2012-04-01

    Available data on the existence of Precambrian metamorphic complexes among the main structures of the Arctic led to the suggestion that a large continental mass existed between Laurentia, Baltica and Siberia - an Arctic continent, more often called Arctida (Zonenshain, Natapov, 1987). It is inferred that as an independent continental mass Arctida was formed after the breakup of Rodinia, and in general it can have a pre-Grenvillian (including Grenvillian) basement age. The breakup of this mass and the collision of its fragments with adjacent cratons led to the formation of heterochronous collisional systems. Arctida probably included the Kara, Novosibirsk, Alaska-Chukotka blocks, the blocks of northern Alaska and the submerged Lomonosov Ridge, small fragments of the Inuit fold belt in the north of Greenland and the Canadian archipelago, the structures of the Svalbard and maybe the Timan-Pechora plates. However the inner structure of this paleocontinent, the mutual configuration of the blocks and its evolution in the Neoproterozoic-Paleozoic is still a matter of discussion. The most accurate way of solving these issues is by using paleomagnetic data, but those are nonexistent for most of the defined blocks. Reliable paleomagnetic determinations for the Neoproterozoic-Paleozoic time interval we are concerned with are available only for fragments of an island arc from Central Taimyr, which are 960 m.y. old (Vernikovsky et al., 2011) and for which the paleomagnetic pole is very close to the pole of Siberia from (Pavlov et al., 2002), and of the Kara microcontinent. This includes three paleomagnetic poles for 500, 450 and 420 Ma (Metelkin et al., 2000; Metelkin et al., 2005). It is those data that made up the basis of the presented paleotectonic reconstructions along with an extensive paleomagnetic database for the cratons of Laurentia, Baltica, Siberia and Gondwana. The paleogeographic position of the cratons is corrected (within the confidence levels for the paleomagnetic poles) according to the general model and the available global reconstructions that include the structures of the Arctic (Scotese, 1997; Lawyer et al., 2002; Golonka et al., 2003, 2006; Cocks, Torsvik, 2002, 2007). The position of those Arctida blocks that lack paleomagnetic data is reconstructed based on geological data.

  7. Neoproterozoic-Paleozoic Evolution of the Arctida Paleocontinent and Plate Reconstructions

    NASA Astrophysics Data System (ADS)

    Vernikovsky, V. A.; Metelkin, D. V.; Vernikovskaya, A. E.; Matushkin, N. Y.; Lobkovsky, L. I.; Shipilov, E. V.; Scientific Team of Arctida

    2011-12-01

    Available data on the existence of Precambrian metamorphic complexes among the main structures of the Arctic led to the suggestion that a large continental mass existed between Laurentia, Baltica and Siberia - an Arctic continent, more often called Arctida (Zonenshain, Natapov, 1987). It is inferred that as an independent continental mass Arctida was formed after the breakup of Rodinia, and in general it can have a pre-Grenvillian (including Grenvillian) basement age. The breakup of this mass and the collision of its fragments with adjacent cratons led to the formation of heterochronous collisional systems. Arctida probably included the Kara, Novosibirsk, Alaska-Chukotka blocks, the blocks of northern Alaska and the submerged Lomonosov Ridge, small fragments of the Inuit fold belt in the north of Greenland and the Canadian archipelago, the structures of the Svalbard and maybe the Timan-Pechora plates. However the inner structure of this paleocontinent, the mutual configuration of the blocks and its evolution in the Neoproterozoic-Paleozoic is still a matter of discussion. The most accurate way of solving these issues is by using paleomagnetic data, but those are nonexistent for most of the defined blocks. Reliable paleomagnetic determinations for the Neoproterozoic-Paleozoic time interval we are concerned with are available only for fragments of an island arc from Central Taimyr, which are 960 m.y. old (Vernikovsky et al., 2011) and for which the paleomagnetic pole is very close to the pole of Siberia from (Pavlov et al., 2002), and of the Kara microcontinent. This includes three paleomagnetic poles for 500, 450 and 420 Ma (Metelkin et al., 2000; Metelkin et al., 2005). It is those data that made up the basis of the presented paleotectonic reconstructions along with an extensive paleomagnetic database for the cratons of Laurentia, Baltica, Siberia and Gondwana. The paleogeographic position of the cratons is corrected (within the confidence levels for the paleomagnetic poles) according to the general model and the available global reconstructions that include the structures of the Arctic (Scotese, 1997; Lawver et al., 2002; Golonka et al., 2003, 2006; Cocks, Torsvik, 2002, 2007). The position of those Arctida blocks that lack paleomagnetic data is reconstructed based on geological data.

  8. Gravity evidence for shaping of the crustal structure of the Ameca graben (Jalisco block northern limit). Western Mexico

    NASA Astrophysics Data System (ADS)

    Alatorre-Zamora, Miguel Angel; Campos-Enríquez, José Oscar; Fregoso-Becerra, Emilia; Quintanar-Robles, Luis; Toscano-Fletes, Roberto; Rosas-Elguera, José

    2018-03-01

    The Ameca tectonic depression (ATD) is located at the NE of the Jalisco Block along the southwestern fringe of the NW-SE trending Tepic-Zacoalco Rift, in the west-central part of the Trans-Mexican Volcanic Belt, western Mexico. To characterize its shallow crustal structure, we conducted a gravity survey based on nine N-S gravity profiles across the western half of the Ameca Valley. The Bouguer residual anomalies are featured by a central low between two zones of positive gravity values with marked gravity gradients. These anomalies have a general NW-SE trend similar to the Tepic-Zacoalco Rift general trend. Basement topography along these profiles was obtained by means of: 1) a Tsuboi's type inverse modeling, and 2) forward modeling. Approximately northward dipping 10° slopes are modeled in the southern half, with south tilted down faulted blocks of the Cretaceous granitic basement and its volcano-sedimentary cover along sub-vertical and intermediate normal faults, whereas southward dipping slopes of almost 15° are observed at the northern half. According to features of the obtained models, this depression corresponds to a slight asymmetric graben. The Ameca Fault is part of the master fault system along its northern limit. The quantitative interpretation shows an approximately 500 to 1100 m thick volcano-sedimentary infill capped by alluvial products. This study has several implications concerning the limit between the Jalisco Block and the Tepic-Zacoalco Rift. The established shallow crustal structure points to the existence of a major listric fault with its detachment surface beneath the Tepic-Zacoalco Rift. The Ameca Fault is interpreted as a secondary listric fault. The models indicate the presence of granitic bodies of the Jalisco Block beneath the TMVB volcanic products of the Tepic-Zacoalco rift. This implies that the limit between these two regional structures is not simple but involves a complex transition zone. A generic model suggests that the extension related normal faulting has been operating as a mechanism in the evolution of this rift. Analysis of seismicity affecting the study area and neighborhood indicates the inferred faults are active.

  9. Finite-Frequency Seismic Imaging of Upper-Mantle Velocity Structures Beneath the South China Continent

    NASA Astrophysics Data System (ADS)

    Qu, P.; Chen, Y. J.; Yu, Y.

    2017-12-01

    South China Continent is major formed from the Paleo-South China plate. The continent has experienced complicated tectonic history after Neoproterozoic. Previous studies suggested some possible model for the collision between South China Continent and North China Continent. Body wave tomography and surface wave tomography are widely used to inverse upper mantle velocity structure. In our study, finite frequency tomography were carried on to get explanation more correctly. We gathered nearly 60000 pieces of teleseismic event records by 166 broad band seismic stations with Mw > 5.5. Here sensitive kernel of ak135 velocity structure was calculated, which is based on Born approximation, and then we applied multi-channel cross-correlation to pick arrival time difference under 3 frequency band. Combining with crust thickness correct from receiver function, we solve the inversion matrix by LSQR method, and get accurate upper mantle structure of P, S velocity. For more accurate results, we apply a method to calculate Vp/Vs ratio, to help to verify the velocity anomaly. The result in this research shows: 1. A strong velocity anomaly exists in the northern of South China Continent, in an area 31°N between 112°-118°E. The anomaly is about . We suggest that, this anomaly is related to the collision from North China Continent. It implies the collision underthrusted to southward. 2. A clearly slow velocity anomaly exists in the northern of Cathaysia block. This low velocity anomaly exist on the boundary of Yangtz block and Cathysian block, it is related to the left over of block collision in early phanerozoic. 3. We recognized some little velocity anomaly exit in the research area. Comparing these velocity anomaly with U-Pb zircon ages, we suggest complicated orogenesis in Phanerozoic is the cause of the formation of these little anomaly. The result in our study support the collision model, which shows the underthrust direction is southward, on the south of Qinling-Dabie Orogen. The anomaly mass is larger than the composite orogenic in Yangtze block.

  10. Nucleic Acid Engineering: RNA Following the Trail of DNA.

    PubMed

    Kim, Hyejin; Park, Yongkuk; Kim, Jieun; Jeong, Jaepil; Han, Sangwoo; Lee, Jae Sung; Lee, Jong Bum

    2016-02-08

    The self-assembly feature of the naturally occurring biopolymer, DNA, has fascinated researchers in the fields of materials science and bioengineering. With the improved understanding of the chemical and structural nature of DNA, DNA-based constructs have been designed and fabricated from two-dimensional arbitrary shapes to reconfigurable three-dimensional nanodevices. Although DNA has been used successfully as a building block in a finely organized and controlled manner, its applications need to be explored. Hence, with the myriad of biological functions, RNA has recently attracted considerable attention to further the application of nucleic acid-based structures. This Review categorizes different approaches of engineering nucleic acid-based structures and introduces the concepts, principles, and applications of each technique, focusing on how DNA engineering is applied as a guide to RNA engineering.

  11. Parallel Geospatial Data Management for Multi-Scale Environmental Data Analysis on GPUs

    NASA Astrophysics Data System (ADS)

    Wang, D.; Zhang, J.; Wei, Y.

    2013-12-01

    As the spatial and temporal resolutions of Earth observatory data and Earth system simulation outputs are getting higher, in-situ and/or post- processing such large amount of geospatial data increasingly becomes a bottleneck in scientific inquires of Earth systems and their human impacts. Existing geospatial techniques that are based on outdated computing models (e.g., serial algorithms and disk-resident systems), as have been implemented in many commercial and open source packages, are incapable of processing large-scale geospatial data and achieve desired level of performance. In this study, we have developed a set of parallel data structures and algorithms that are capable of utilizing massively data parallel computing power available on commodity Graphics Processing Units (GPUs) for a popular geospatial technique called Zonal Statistics. Given two input datasets with one representing measurements (e.g., temperature or precipitation) and the other one represent polygonal zones (e.g., ecological or administrative zones), Zonal Statistics computes major statistics (or complete distribution histograms) of the measurements in all regions. Our technique has four steps and each step can be mapped to GPU hardware by identifying its inherent data parallelisms. First, a raster is divided into blocks and per-block histograms are derived. Second, the Minimum Bounding Boxes (MBRs) of polygons are computed and are spatially matched with raster blocks; matched polygon-block pairs are tested and blocks that are either inside or intersect with polygons are identified. Third, per-block histograms are aggregated to polygons for blocks that are completely within polygons. Finally, for blocks that intersect with polygon boundaries, all the raster cells within the blocks are examined using point-in-polygon-test and cells that are within polygons are used to update corresponding histograms. As the task becomes I/O bound after applying spatial indexing and GPU hardware acceleration, we have developed a GPU-based data compression technique by reusing our previous work on Bitplane Quadtree (or BPQ-Tree) based indexing of binary bitmaps. Results have shown that our GPU-based parallel Zonal Statistic technique on 3000+ US counties over 20+ billion NASA SRTM 30 meter resolution Digital Elevation (DEM) raster cells has achieved impressive end-to-end runtimes: 101 seconds and 46 seconds a low-end workstation equipped with a Nvidia GTX Titan GPU using cold and hot cache, respectively; and, 60-70 seconds using a single OLCF TITAN computing node and 10-15 seconds using 8 nodes. Our experiment results clearly show the potentials of using high-end computing facilities for large-scale geospatial processing.

  12. Coding tools investigation for next generation video coding based on HEVC

    NASA Astrophysics Data System (ADS)

    Chen, Jianle; Chen, Ying; Karczewicz, Marta; Li, Xiang; Liu, Hongbin; Zhang, Li; Zhao, Xin

    2015-09-01

    The new state-of-the-art video coding standard, H.265/HEVC, has been finalized in 2013 and it achieves roughly 50% bit rate saving compared to its predecessor, H.264/MPEG-4 AVC. This paper provides the evidence that there is still potential for further coding efficiency improvements. A brief overview of HEVC is firstly given in the paper. Then, our improvements on each main module of HEVC are presented. For instance, the recursive quadtree block structure is extended to support larger coding unit and transform unit. The motion information prediction scheme is improved by advanced temporal motion vector prediction, which inherits the motion information of each small block within a large block from a temporal reference picture. Cross component prediction with linear prediction model improves intra prediction and overlapped block motion compensation improves the efficiency of inter prediction. Furthermore, coding of both intra and inter prediction residual is improved by adaptive multiple transform technique. Finally, in addition to deblocking filter and SAO, adaptive loop filter is applied to further enhance the reconstructed picture quality. This paper describes above-mentioned techniques in detail and evaluates their coding performance benefits based on the common test condition during HEVC development. The simulation results show that significant performance improvement over HEVC standard can be achieved, especially for the high resolution video materials.

  13. Tunable Affinity and Molecular Architecture Lead to Diverse Self-Assembled Supramolecular Structures in Thin Films

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

    Hsu, Chih-Hao; Dong, Xue-Hui; Lin, Zhiwei

    2015-12-03

    The self-assembly behaviors of specifically designed giant surfactants are systematically studied in thin films using grazing incident X-ray and transmission electron microscopy (TEM), focusing on the effects of head surface functionalities and molecular architectures on nanostructure formation. Two molecular nanoparticles (MNPs) with different affinities, i.e., hydrophilic carboxylic acid functionalized [60]fullerene (AC60) and omniphobic fluorinated polyhedral oligomeric silsesquioxane (FPOSS), are utilized as heads of the giant surfactants. By covalently tethering these functional MNPs onto the chain end or the junction point of polystyrene-block-poly(ethylene oxide) (PS-b-PEO) diblock copolymer, linear and star-like giant surfactants possess distinct molecular architectures are constructed. With fixed lengthmore » of the PEO block, the molecular weight change of the PS block originates the phase formation and transition. Due to the distinct affinity, the AC60-based giant surfactants form two-component morphologies, while three-component morphologies are found in the FPOSS-based ones. A PS block stretching parameter is introduced to characterize the PS chain conformation in different morphologies. The highly diverse self-assembly behaviors and the tunable dimensions in thin films suggest the giant surfactants could be a promising and robust platform for nanolithography applications.« less

  14. Comments on the Yule Marble Haines block: potential replacement, Tomb of the Unknown Soldier, Arlington National Cemetery

    USGS Publications Warehouse

    Mossotti, Victor G.

    2014-01-01

    Marble for the Tomb of the Unknown Soldier at Arlington National Cemetery was cut from the Colorado Yule Marble Quarry in 1931. Although anecdotal reports suggest that cracks were noticed in the main section of the monument shortly after its installation at the Arlington National Cemetery in Arlington, Virginia, detailed documentation of the extent of cracking did not appear until 1963. Although debate continues as to whether the main section of the Tomb of the Unknowns monument should be repaired or replaced, Mr. John S. Haines of Glenwood Springs, Colorado, in anticipation of the permanent closing of the Yule Quarry, donated a 58-ton block of Yule Marble, the so-called Haines block, as a potential backup. The brief study reported here was conducted during mid-summer 2009 at the behest of the superintendent of Arlington National Cemetery. The field team entered the subterranean Yule Marble Quarry with the Chief Extraction Engineer in order to contrast the method used for extraction of the Haines block with the method that was probably used to extract the marble block that is now cracked. Based on surficial inspection and shallow coring of the Haines block, and on the nature of crack propagation in Yule Marble as judged by close inspection of a large collection of surrogate Yule Marble blocks, the team found the block to be structurally sound and cosmetically equivalent to the marble used for the current monument. If the Haines block were needed, it would be an appropriate replacement for the existing cracked section of the Tomb of the Unknown Soldier Monument.

  15. Vertical Scan (V-SCAN) for 3-D Grid Adaptive Mesh Refinement for an atmospheric Model Dynamical Core

    NASA Astrophysics Data System (ADS)

    Andronova, N. G.; Vandenberg, D.; Oehmke, R.; Stout, Q. F.; Penner, J. E.

    2009-12-01

    One of the major building blocks of a rigorous representation of cloud evolution in global atmospheric models is a parallel adaptive grid MPI-based communication library (an Adaptive Blocks for Locally Cartesian Topologies library -- ABLCarT), which manages the block-structured data layout, handles ghost cell updates among neighboring blocks and splits a block as refinements occur. The library has several modules that provide a layer of abstraction for adaptive refinement: blocks, which contain individual cells of user data; shells - the global geometry for the problem, including a sphere, reduced sphere, and now a 3D sphere; a load balancer for placement of blocks onto processors; and a communication support layer which encapsulates all data movement. A major performance concern with adaptive mesh refinement is how to represent calculations that have need to be sequenced in a particular order in a direction, such as calculating integrals along a specific path (e.g. atmospheric pressure or geopotential in the vertical dimension). This concern is compounded if the blocks have varying levels of refinement, or are scattered across different processors, as can be the case in parallel computing. In this paper we describe an implementation in ABLCarT of a vertical scan operation, which allows computing along vertical paths in the correct order across blocks transparent to their resolution and processor location. We test this functionality on a 2D and a 3D advection problem, which tests the performance of the model’s dynamics (transport) and physics (sources and sinks) for different model resolutions needed for inclusion of cloud formation.

  16. Calculation of electronic coupling matrix elements for ground and excited state electron transfer reactions: Comparison of the generalized Mulliken-Hush and block diagonalization methods

    NASA Astrophysics Data System (ADS)

    Cave, Robert J.; Newton, Marshall D.

    1997-06-01

    Two independent methods are presented for the nonperturbative calculation of the electronic coupling matrix element (Hab) for electron transfer reactions using ab initio electronic structure theory. The first is based on the generalized Mulliken-Hush (GMH) model, a multistate generalization of the Mulliken Hush formalism for the electronic coupling. The second is based on the block diagonalization (BD) approach of Cederbaum, Domcke, and co-workers. Detailed quantitative comparisons of the two methods are carried out based on results for (a) several states of the system Zn2OH2+ and (b) the low-lying states of the benzene-Cl atom complex and its contact ion pair. Generally good agreement between the two methods is obtained over a range of geometries. Either method can be applied at an arbitrary nuclear geometry and, as a result, may be used to test the validity of the Condon approximation. Examples of nonmonotonic behavior of the electronic coupling as a function of nuclear coordinates are observed for Zn2OH2+. Both methods also yield a natural definition of the effective distance (rDA) between donor (D) and acceptor (A) sites, in contrast to earlier approaches which required independent estimates of rDA, generally based on molecular structure data.

  17. Repair, Evaluation, Maintenance, and Rehabilitation Research Program: Case Histories of Corps Breakwater and Jetty Structures. Report 5. North Atlantic Division

    DTIC Science & Technology

    1988-11-01

    TERMS (Continue on reverse if necessary and identify by block number) FIELD GROUP SUB-GROUP Breakwater REMR (Repair, Evaluation, Concrete armor units...Maintenance, and Rehabilitation) Jetty Rubble-mound structures 19. ABSTRACT (Continue on reverse if necessary and identify by block number) :-This...have been repaired since construction. Other construction materials that have been used include steel, dolosse, concrete cap, concrete block , and

  18. Expansion and improvements of the FORMA system for response and load analysis. Volume 1: Programming manual

    NASA Technical Reports Server (NTRS)

    Wohlen, R. L.

    1976-01-01

    Techniques are presented for the solution of structural dynamic systems on an electronic digital computer using FORMA (FORTRAN Matrix Analysis). FORMA is a library of subroutines coded in FORTRAN 4 for the efficient solution of structural dynamics problems. These subroutines are in the form of building blocks that can be put together to solve a large variety of structural dynamics problems. The obvious advantage of the building block approach is that programming and checkout time are limited to that required for putting the blocks together in the proper order.

  19. Two Decades of Structure Building

    PubMed Central

    Gernsbacher, Morton Ann

    2014-01-01

    During the past decade I have been developing a very simple framework for describing the cognitive processes and mechanisms involved in discourse comprehension. I call this framework the Structure Building Framework, and it is based on evidence provided during the first decade of discourse processing research. According to the Structure Building Framework, the goal of comprehension is to build coherent mental representations or structures. Comprehenders build each structure by first laying a foundation. Comprehenders develop mental structures by mapping on new information when that information coheres or relates to previous information. However, when the incoming information is less related, comprehenders shift and attach a new substructure. The building blocks of mental structures are memory nodes, which are activated by incoming stimuli and controlled by two cognitive mechanisms: suppression and enhancement. In this article, first I review the seminal work on which the Structure Building Framework is based (the first decade of structure building research); then I recount the research I have conducted to test the Structure Building Framework (the second decade of structure building research). PMID:25484476

  20. Asymmetric block copolymer membranes with ultrahigh porosity and hierarchical pore structure by plain solvent evaporation.

    PubMed

    Yu, H; Qiu, X; Behzad, A R; Musteata, V; Smilgies, D-M; Nunes, S P; Peinemann, K-V

    2016-10-04

    Membranes with a hierarchical porous structure could be manufactured from a block copolymer blend by pure solvent evaporation. Uniform pores in a 30 nm thin skin layer supported by a macroporous structure were formed. This new process is attractive for membrane production because of its simplicity and the lack of liquid waste.

  1. Functionalized coronenes: synthesis, solid structure, and properties.

    PubMed

    Wu, Di; Zhang, Hua; Liang, Jinhua; Ge, Haojie; Chi, Chunyan; Wu, Jishan; Liu, Sheng Hua; Yin, Jun

    2012-12-21

    The construction of coronenes using simple building blocks is a challenging task. In this work, triphenylene was used as a building block to construct functionalized coronenes, and their solid structures and optoelectronic properties were investigated. The single crystal structures showed that coronenes have different packing motifs. Their good solubility and photostability make them potential solution-processable candidates for organic devices.

  2. Novel Hydrogels from Telechelic Polymers

    NASA Astrophysics Data System (ADS)

    Taribagil, Rajiv R.

    The last two decades have seen telechelic polymers support an increasing number of applications as stabilizers and flow modifiers in fields as varied as pharmaceutics, paints and oil recovery. Mainly consisting of a long hydrophilic block end-capped with hydrophobic blocks, these polymers form gels at modest concentrations, comprising hydrophobic junctions with hydrophilic blocks bridging these junctions. This thesis examines two different types of telechelic polymer hydrogels: concentrated dispersions of telechelic triblock copolymers and dilute solutions of wormlike micelles cross-linked by hydrophobically end-capped polymers. Aqueous gels of telechelic poly(ethylene oxide) (PEO)-based triblock polymers, with homo and hetero combinations of 1,2-polybutadiene (PB) and poly(perfluoropropylene oxide) (PFPO) as hydrophobic end-blocks, were investigated using a combination of cryogenic scanning electron microscopy and small-angle neutron scattering. The PB-b-PEO-b-PB copolymers formed networks of spherical micelles at all concentrations as expected, albeit with significant spatial heterogeneity that diminished with increasing concentration. The PFPO-b-PEO-b-PFPO copolymers also formed networks by aggregation of the end-blocks, but the PFPO blocks tended to adopt disk-like or even sheet-like structures. This is attributed to the extremely high interfacial tension of PFPO with water and is consistent with the "super-strong" segregation regime behavior. The heterotelechelic PB-b-PEO- b-PFPO terpolymers adopted a quite different structure, namely an intricate bicontinuous open-cell foam, with cells on the order of 500 nm in size and cell walls composed of PFPO disks embedded in PB sheets. These various network structures illustrate the potential of using end-block chemistry to manipulate both the morphology and the physical properties of polymer gels. Dilute aqueous solutions containing 1 wt% cetyltrimethylammonium tosylate, a surfactant well recognized to form wormlike micelles, and low concentrations of hydrophobically end-capped poly(ethylene oxide), were investigated using dynamic mechanical spectroscopy and small-angle neutron scattering. The detailed examination shows that addition of as little as 0.1 wt% of the polymer to the dilute wormlike micelle solution leads to a massive enhancement in its viscoelastic response. This phenomenon raises the possibility of significantly reducing the amount of additive required to achieve a desired rheological profile, with concomitant advantages in both cost and environmental impact.

  3. DNA-nanoparticle assemblies go organic: macroscopic polymeric materials with nanosized features.

    PubMed

    Mentovich, Elad D; Livanov, Konstantin; Prusty, Deepak K; Sowwan, Mukules; Richter, Shachar

    2012-05-30

    One of the goals in the field of structural DNA nanotechnology is the use of DNA to build up 2- and 3-D nanostructures. The research in this field is motivated by the remarkable structural features of DNA as well as by its unique and reversible recognition properties. Nucleic acids can be used alone as the skeleton of a broad range of periodic nanopatterns and nanoobjects and in addition, DNA can serve as a linker or template to form DNA-hybrid structures with other materials. This approach can be used for the development of new detection strategies as well as nanoelectronic structures and devices. Here we present a new method for the generation of unprecedented all-organic conjugated-polymer nanoparticle networks guided by DNA, based on a hierarchical self-assembly process. First, microphase separation of amphiphilic block copolymers induced the formation of spherical nanoobjects. As a second ordering concept, DNA base pairing has been employed for the controlled spatial definition of the conjugated-polymer particles within the bulk material. These networks offer the flexibility and the diversity of soft polymeric materials. Thus, simple chemical methodologies could be applied in order to tune the network's electrical, optical and mechanical properties. One- two- and three-dimensional networks have been successfully formed. Common to all morphologies is the integrity of the micelles consisting of DNA block copolymer (DBC), which creates an all-organic engineered network.

  4. Mathematics and Structural Learning. Final Report.

    ERIC Educational Resources Information Center

    Scandura, Joseph M.

    This report contains four papers describing research based on the view of mathematical knowledge as a hierarchy of "rules." The first paper: "The Role of Rules in Behavior" was abstracted in ED 040 036 (October 1970). The second paper: "A Theory of Mathematical Knowledge" defends the thesis that rules are the basic building blocks of mathematical…

  5. Regional framework, structural and petroleum aspects of rift basins in Niger, Chad and the Central African Republic (C.A.R.)

    NASA Astrophysics Data System (ADS)

    Genik, G. J.

    1992-10-01

    This paper overviews the regional framework, tectonic, structural and petroleum aspects of rifts in Niger, Chad and the C.A.R. The data base is from mainly proprietary exploration work consisting of some 50,000 kilometres of seismic profiles, 50 exploration wells, one million square kilometres of aeromagnetics coverage and extensive gravity surveys. There have been 13 oil and two oil and gas discoveries. A five phased tectonic history dating from the Pan African orogeny (750-550 MY B.P.) to the present suggests that the Western Central African Rift System (WCAS) with its component West African Rift Subsystem (WAS) and Central African Subsystem (CAS) formed mainly by the mechanical separation of African crustal blocks during the Early Cretaceous. Among the resulting rift basins in Niger, Chad and the C.A.R., seven are in the WAS—Grein, Kafra, Tenere. Tefidet, Termit, Bongor, and N'Dgel Edgi and three, Doba, Doseo, and Salamat are in the CAS. The WAS basins in Niger and Chad are all extensional and contain more than 14,000 m of continental to marine Early Cretaceous to Recent clastic sediments and minor amounts of volcanics. Medium to light oil (20° API-46° API) and gas have been discovered in the Termit basin in reservoir, source and seal beds of Late Cretaceous and Palaeogene age. The most common structural styles are extensional normal fault blocks and transtensional synthetic and antithetic normal fault blocks. The CAS Doba, Doseo and Salamat are extensional to transtensional rift basins containing up to 7500 m of terrestrial mainly Early Cretaceous clastics. Heavy to light oil (15°-39° API) and gas have been discovered in Doba and Doseo basins. Source rocks are Early Cretaceous lacustrine shales, whereas reservoirs and seals are both Early and Late Cretaceous. Dominant structural styles are extensional and transtensional fault blocks, transpressional anticlines and flower structures. The existence of a total rift basin sediment volume of more than one million cubic kilometres with structured reservoir, source and seal rocks favours the generation, migration and entrapment of additional significant volumes of hydrocarbons in many of these basins.

  6. Modeling Framework for Fracture in Multiscale Cement-Based Material Structures

    PubMed Central

    Qian, Zhiwei; Schlangen, Erik; Ye, Guang; van Breugel, Klaas

    2017-01-01

    Multiscale modeling for cement-based materials, such as concrete, is a relatively young subject, but there are already a number of different approaches to study different aspects of these classical materials. In this paper, the parameter-passing multiscale modeling scheme is established and applied to address the multiscale modeling problem for the integrated system of cement paste, mortar, and concrete. The block-by-block technique is employed to solve the length scale overlap challenge between the mortar level (0.1–10 mm) and the concrete level (1–40 mm). The microstructures of cement paste are simulated by the HYMOSTRUC3D model, and the material structures of mortar and concrete are simulated by the Anm material model. Afterwards the 3D lattice fracture model is used to evaluate their mechanical performance by simulating a uniaxial tensile test. The simulated output properties at a lower scale are passed to the next higher scale to serve as input local properties. A three-level multiscale lattice fracture analysis is demonstrated, including cement paste at the micrometer scale, mortar at the millimeter scale, and concrete at centimeter scale. PMID:28772948

  7. Comparison of compressive strength of paving block with a mixture of Sinabung ash and paving block with a mixture of lime

    NASA Astrophysics Data System (ADS)

    Hastuty, I. P.; Sembiringand Nursyamsi, I. S.

    2018-02-01

    Paving block is one of the material used as the top layer of road structure besides asphalt and concrete paving block is usually made of mixed material such as Portland cement or other adhesive material, water, and aggregate. People nowadays prefer paving block compared to other pavement such as concrete or asphalt. Their interest toward the use of paving block increase because paving block is an eco-friendly construction which is very useful in helping soil water conservation, can be done faster, has easier installation and maintenance, has a variety of shades that increase the aesthetic value, also costs cheaper than the other. Preparation of the specimens with a mixture of Sinabung ash and a mixture of Sinabung ash and lime are implemented with a mixture ratio of cement : sand : stone ash is 1: 2 : 3. The mixture is used as a substitute material by reducing the percentage amount of the weight of the cement with the composition ratio variation based on the comparative volume category of the paving block aggregate, i.e. 0%, 5%, 10%, 15%, 20%, and 25%. The result of this research shows that the maximum compressive strength value is 42.27 Mpa, it was obtained from a mixture of 10% lime with curing time 28 days. The maximum compressive strength value which is obtained from the mixture of sinabung ash is 41.60 Mpa, it was obtained from a mixture of 15% sinabung ash. From the use of these two materials, paving blocks produced are classified as paving blocks quality A and B (350 - 400 Mpa) in accordance to specification from SNI 03-0691-1996.

  8. A simple theory of molecular organization in fullerene-containing liquid crystals

    NASA Astrophysics Data System (ADS)

    Peroukidis, S. D.; Vanakaras, A. G.; Photinos, D. J.

    2005-10-01

    Systematic efforts to synthesize fullerene-containing liquid crystals have produced a variety of successful model compounds. We present a simple molecular theory, based on the interconverting shape approach [Vanakaras and Photinos, J. Mater. Chem. 15, 2002 (2005)], that relates the self-organization observed in these systems to their molecular structure. The interactions are modeled by dividing each molecule into a number of submolecular blocks to which specific interactions are assigned. Three types of blocks are introduced, corresponding to fullerene units, mesogenic units, and nonmesogenic linkage units. The blocks are constrained to move on a cubic three-dimensional lattice and molecular flexibility is allowed by retaining a number of representative conformations within the block representation of the molecule. Calculations are presented for a variety of molecular architectures including twin mesogenic branch monoadducts of C60, twin dendromesogenic branch monoadducts, and conical (badminton shuttlecock) multiadducts of C60. The dependence of the phase diagrams on the interaction parameters is explored. In spite of its many simplifications and the minimal molecular modeling used (three types of chemically distinct submolecular blocks with only repulsive interactions), the theory accounts remarkably well for the phase behavior of these systems.

  9. Mode jumping of split-ring resonator metamaterials controlled by high-permittivity BST and incident electric fields

    PubMed Central

    Fu, Xiaojian; Zeng, Xinxi; Cui, Tie Jun; Lan, Chuwen; Guo, Yunsheng; Zhang, Hao Chi; Zhang, Qian

    2016-01-01

    We investigate the resonant modes of split-ring resonator (SRR) metamaterials that contain high-permittivity BST block numerically and experimentally. We observe interesting mode-jumping phenomena from the BST-included SRR absorber structure as the excitation wave is incident perpendicularly to the SRR plane. Specifically, when the electric field is parallel to the SRR gap, the BST block in the gap will induce a mode jumping from the LC resonance to plasmonic resonance (horizontal electric-dipole mode), because the displacement current excited by the Mie resonance in the dielectric block acts as a current channel in the gap. When the electric field is perpendicular to the gap side, the plasmonic resonance mode (vertical electric-dipole mode) in SRR changes to two joint modes contributed simultaneously by the back layer, SRR and BST block, as a result of connected back layer and SRR layer by the displacement current in the BST dielectric block. Based on the mode jumping effect as well as temperature and electric-field dependent dielectric constant, the BST-included SRR metamaterials may have great potentials for the applications in electromagnetic switches and widely tunable metamaterial devices. PMID:27502844

  10. Accelerating nuclear configuration interaction calculations through a preconditioned block iterative eigensolver

    DOE PAGES

    Shao, Meiyue; Aktulga, H.  Metin; Yang, Chao; ...

    2017-09-14

    In this paper, we describe a number of recently developed techniques for improving the performance of large-scale nuclear configuration interaction calculations on high performance parallel computers. We show the benefit of using a preconditioned block iterative method to replace the Lanczos algorithm that has traditionally been used to perform this type of computation. The rapid convergence of the block iterative method is achieved by a proper choice of starting guesses of the eigenvectors and the construction of an effective preconditioner. These acceleration techniques take advantage of special structure of the nuclear configuration interaction problem which we discuss in detail. Themore » use of a block method also allows us to improve the concurrency of the computation, and take advantage of the memory hierarchy of modern microprocessors to increase the arithmetic intensity of the computation relative to data movement. Finally, we also discuss the implementation details that are critical to achieving high performance on massively parallel multi-core supercomputers, and demonstrate that the new block iterative solver is two to three times faster than the Lanczos based algorithm for problems of moderate sizes on a Cray XC30 system.« less

  11. Automatic blocking for complex three-dimensional configurations

    NASA Technical Reports Server (NTRS)

    Dannenhoffer, John F., III

    1995-01-01

    A new blocking technique for complex three-dimensional configurations is described. This new technique is based upon the concept of an abstraction, or squared-up representation, of the configuration and the associated grid. By allowing the user to describe blocking requirements in natural terms (such as 'wrap a grid around this leading edge' or 'make all grid lines emanating from this wall orthogonal to it'), users can quickly generate complex grids around complex configurations, while still maintaining a high level of control where desired. An added advantage of the abstraction concept is that once a blocking is defined for a class of configurations, it can be automatically applied to other configurations of the same class, making the new technique particularly well suited for the parametric variations which typically occur during design processes. Grids have been generated for a variety of real-world, two- and three-dimensional configurations. In all cases, the time required to generate the grid, given just an electronic form of the configuration, was at most a few days. Hence with this new technique, the generation of a block-structured grid is only slightly more expensive than the generation of an unstructured grid for the same configuration.

  12. Nodal Diffusion Burnable Poison Treatment for Prismatic Reactor Cores

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

    A. M. Ougouag; R. M. Ferrer

    2010-10-01

    The prismatic block version of the High Temperature Reactor (HTR) considered as a candidate Very High Temperature Reactor (VHTR)design may use burnable poison pins in locations at some corners of the fuel blocks (i.e., assembly equivalent structures). The presence of any highly absorbing materials, such as these burnable poisons, within fuel blocks for hexagonal geometry, graphite-moderated High Temperature Reactors (HTRs) causes a local inter-block flux depression that most nodal diffusion-based method have failed to properly model or otherwise represent. The location of these burnable poisons near vertices results in an asymmetry in the morphology of the assemblies (or blocks). Hencemore » the resulting inadequacy of traditional homogenization methods, as these “spread” the actually local effect of the burnable poisons throughout the assembly. Furthermore, the actual effect of the burnable poison is primarily local with influence in its immediate vicinity, which happens to include a small region within the same assembly as well as similar regions in the adjacent assemblies. Traditional homogenization methods miss this artifact entirely. This paper presents a novel method for treating the local effect of the burnable poison explicitly in the context of a modern nodal method.« less

  13. Molecular bases of protective immune responses against botulinum neurotoxin A--how antitoxin antibodies block its action.

    PubMed

    Atassi, M Zouhair; Dolimbek, Behzod Z; Steward, Lance E; Aoki, K Roger

    2007-01-01

    In studies from this laboratory, we localized the regions on the H chain of botulinum neurotoxin A (BoNT/A) that are recognized by anti-BoNT/A antibodies (Abs) and block the activity of the toxin in vivo. These Abs were obtained from cervical dystonia patients who had been treated with BoNT/A and had become unresponsive to the treatment, as well as blocking Abs raised in mouse, horse, and chicken. We also localized the regions involved in BoNT/A binding to mouse brain synaptosomes (snp). Comparison of spatial proximities in the three-dimensional structure of the Ab-binding regions and the snp binding showed that except for one, the Ab-binding regions either coincide or overlap with the snp regions. It should be folly expected that protective Abs when bound to the toxin at sites that coincide or overlap with snp binding would prevent the toxin from binding to nerve synapse and therefore block toxin entry into the neuron. Thus, analysis of the locations of the Ab-binding and the snp-binding regions provides a molecular rationale for the ability of protecting Abs to block BoNT/A action in vivo.

  14. Accelerating nuclear configuration interaction calculations through a preconditioned block iterative eigensolver

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

    Shao, Meiyue; Aktulga, H.  Metin; Yang, Chao

    In this paper, we describe a number of recently developed techniques for improving the performance of large-scale nuclear configuration interaction calculations on high performance parallel computers. We show the benefit of using a preconditioned block iterative method to replace the Lanczos algorithm that has traditionally been used to perform this type of computation. The rapid convergence of the block iterative method is achieved by a proper choice of starting guesses of the eigenvectors and the construction of an effective preconditioner. These acceleration techniques take advantage of special structure of the nuclear configuration interaction problem which we discuss in detail. Themore » use of a block method also allows us to improve the concurrency of the computation, and take advantage of the memory hierarchy of modern microprocessors to increase the arithmetic intensity of the computation relative to data movement. Finally, we also discuss the implementation details that are critical to achieving high performance on massively parallel multi-core supercomputers, and demonstrate that the new block iterative solver is two to three times faster than the Lanczos based algorithm for problems of moderate sizes on a Cray XC30 system.« less

  15. Changes of hydrodynamic parameters on mountain stream bed within the block ramp influence and possibility of their use for integrated river management

    NASA Astrophysics Data System (ADS)

    Radecki-Pawlik, Artur; Plesiński, Karol

    2016-04-01

    In modern river management practices and philosophy one can notice coming more into use ecological friendly hydraulic structures. Those, which are especially needed for river training works, as far as expectation of Water Framework Directive is concerned, are block ramps which are hydraulic structures working similar to riffles known very well from fluvial geomorphology studies and are natural features in streams and rivers. What is important well designed block ramps do not stop fish and invertebrates against migrating, provide natural and esthetical view being built within the river channel, still working as hydraulic engineering structures and might be used in river management in different river ecosystems. The main aim of the research was to describe changes of values of hydrodynamics parameters upstream and downstream of the block ramps and to find out their influence on hydrodynamics of the stream. The study was undertaken on the Porębianka River in the Gorce Mountains, Polish Carpathians. Observed hydrodynamic parameters within the reach of the block ramps depend on the location of measuring point and the influence of individual part of the structure. We concluded that: 1. Hydrodynamic parameters close to block ramps depend on the location of the measurement points in relation to particular elements of the structure; 2. The highest value of velocities don't cause the highest force values, which acting on the bed of the watercourse, because they are rather related to the water level of the channel; 3. The values of mean velocities, shear velocities and shear stresses were similar upstream and downstream the block ramps, which means that the structures stabilize the river bed. This study was performed within the scope of the Science Activity money from Ministry of High Education and Young Scientist's Activity Money of Department of Hydraulics Engineering and Geotechnique, University of Agriculture, Cracow, Poland

  16. Comparative Study Of Artificial Intelligence Techniques As Applied To The Location Of Address Blocks On Mail Pieces

    NASA Astrophysics Data System (ADS)

    Koljonen, Juha T.; Glickman, Frederick R.

    1989-03-01

    Rule-based reasoning when applied to locating destination addresses on mail pieces can enhance system performance and accuracy. One of the critical steps in the automatic reading and sorting of mail by machine is in locating the block of text that is the destination address on a mail piece. This is complicated by the variation of global structure on mail piece faces, e.g., return and destination addresses can be anywhere on the mail piece, in any orientation and of any size. Compounding the problem is the addition of extraneous text and graphics such as advertising.

  17. Application of Transfer Matrix Approach to Modeling and Decentralized Control of Lattice-Based Structures

    NASA Technical Reports Server (NTRS)

    Cramer, Nick; Swei, Sean Shan-Min; Cheung, Kenny; Teodorescu, Mircea

    2015-01-01

    This paper presents a modeling and control of aerostructure developed by lattice-based cellular materials/components. The proposed aerostructure concept leverages a building block strategy for lattice-based components which provide great adaptability to varying ight scenarios, the needs of which are essential for in- ight wing shaping control. A decentralized structural control design is proposed that utilizes discrete-time lumped mass transfer matrix method (DT-LM-TMM). The objective is to develop an e ective reduced order model through DT-LM-TMM that can be used to design a decentralized controller for the structural control of a wing. The proposed approach developed in this paper shows that, as far as the performance of overall structural system is concerned, the reduced order model can be as e ective as the full order model in designing an optimal stabilizing controller.

  18. Three-dimensional lithospheric electrical structure of Southern Granulite Terrain, India and its tectonic implications

    NASA Astrophysics Data System (ADS)

    Patro, Prasanta K.; Sarma, S. V. S.; Naganjaneyulu, K.

    2014-01-01

    crustal as well as the upper mantle lithospheric electrical structure of the Southern Granulite Terrain (SGT) is evaluated, using the magnetotelluric (MT) data from two parallel traverses: one is an 500 km long N-S trending traverse across SGT and another a 200 km long traverse. Data space Occam 3-D inversion was used to invert the MT data. The electrical characterization of lithospheric structure in SGT shows basically a highly resistive (several thousands of Ohm meters) upper crustal layer overlying a moderately resistive (a few hundred Ohm meters) lower crustal layer which in turn is underlain by the upper mantle lithosphere whose resistivity shows significant changes along the traverse. The highly resistive upper crustal layer is interspersed with four major conductive features with three of them cutting across the crustal column, bringing out a well-defined crustal block structure in SGT with individual highly resistive blocks showing correspondence to the geologically demarcated Salem, Madurai, and Trivandrum blocks. The 3-D model also brought out a well-defined major crustal conductor located in the northern half of the Madurai block. The electrical characteristics of this south dipping conductor and its close spatial correlation with two of the major structural elements, viz., Karur-Oddanchatram-Kodaikanal Shear Zone and Karur-Kamban-Painavu-Trichur Shear Zone, suggest that this conductive feature is closely linked to the subduction-collision tectonic processes in the SGT, and it is inferred that the Archean Dharwar craton/neoproterozoic SGT terrain boundary lies south of the Palghat-Cauvery shear zone. The results also showed that the Achankovil shear zone is characterized by a well-defined north dipping conductive feature. The resistive block adjoining this conductor on the southern side, representing the Trivandrum block, is shown to be downthrown along this north dipping crustal conductor relative to the Madurai block, suggesting a northward movement of Trivandrum block colliding against the Madurai block. The lithospheric upper mantle electrical structure of the SGT up to a depth of 100 km may be broadly divided into two distinctly different segments, viz., northern and southern segments. The northern lithospheric segment, over a major part, is characterized by a thick resistive upper mantle, while the southern one is characterized by a dominantly conductive medium suggesting a relatively thinned lithosphere in the southern segment.

  19. The Crustal and Mantle Velocity Structure in Central Asia from 3D Travel Time Tomography

    DTIC Science & Technology

    2010-09-01

    the Turan plate, and the Tarim block. This geologically and tectonically complicated area is also one of the most seismically active regions in the...Asia features large blocks such as the Indian plate, the Afghan block, the Turan plate, and the Tarim block. This geologically and tectonically

  20. Encoders for block-circulant LDPC codes

    NASA Technical Reports Server (NTRS)

    Divsalar, Dariush (Inventor); Abbasfar, Aliazam (Inventor); Jones, Christopher R. (Inventor); Dolinar, Samuel J. (Inventor); Thorpe, Jeremy C. (Inventor); Andrews, Kenneth S. (Inventor); Yao, Kung (Inventor)

    2009-01-01

    Methods and apparatus to encode message input symbols in accordance with an accumulate-repeat-accumulate code with repetition three or four are disclosed. Block circulant matrices are used. A first method and apparatus make use of the block-circulant structure of the parity check matrix. A second method and apparatus use block-circulant generator matrices.

  1. Parallel SOR methods with a parabolic-diffusion acceleration technique for solving an unstructured-grid Poisson equation on 3D arbitrary geometries

    NASA Astrophysics Data System (ADS)

    Zapata, M. A. Uh; Van Bang, D. Pham; Nguyen, K. D.

    2016-05-01

    This paper presents a parallel algorithm for the finite-volume discretisation of the Poisson equation on three-dimensional arbitrary geometries. The proposed method is formulated by using a 2D horizontal block domain decomposition and interprocessor data communication techniques with message passing interface. The horizontal unstructured-grid cells are reordered according to the neighbouring relations and decomposed into blocks using a load-balanced distribution to give all processors an equal amount of elements. In this algorithm, two parallel successive over-relaxation methods are presented: a multi-colour ordering technique for unstructured grids based on distributed memory and a block method using reordering index following similar ideas of the partitioning for structured grids. In all cases, the parallel algorithms are implemented with a combination of an acceleration iterative solver. This solver is based on a parabolic-diffusion equation introduced to obtain faster solutions of the linear systems arising from the discretisation. Numerical results are given to evaluate the performances of the methods showing speedups better than linear.

  2. Composite Reflective Absorptive IR-Blocking Filters Embedded in Metamaterial Antireflection Coated Silicon

    NASA Technical Reports Server (NTRS)

    Munson, C. D.; Choi, S. K.; Coughlin, K. P.; McMahon, J. J.; Miller, K. H.; Page, L. A.; Wollack, E. J.

    2017-01-01

    Infrared (IR)-blocking filters are crucial for controlling the radiative loading on cryogenic systems and for optimizing the sensitivity of bolometric detectors in the far-IR. We present a new IR filter approach based on a combination of patterned frequency-selective structures on silicon and a thin (2575 micron thick) absorptive composite based on powdered reststrahlen absorbing materials. For a 300 K blackbody, this combination reflects approximately 50% of the incoming light and blocks greater than.99.8% of the total power with negligible thermal gradients and excellent low-frequency transmission. This allows a reduction in the IR thermal loading to negligible levels in a single cold filter. These composite filters are fabricated on silicon substrates, which provide excellent thermal transport laterally through the filter and ensure that the entire area of the absorptive filter stays near the bath temperature. A metamaterial antireflection coating cut into these substrates reduces in-band reflections to below 1%, and the in-band absorption of the powder mix is below 1% for signal bands below 750 GHz. This type of filter can be directly incorporated into silicon refractive optical elements.

  3. The improvement of GaN-based LED grown on concave nano-pattern sapphire substrate with SiO2 blocking layer

    NASA Astrophysics Data System (ADS)

    Lin, Jyun-Hao; Huang, Shyh-Jer; Su, Yan-Kuin; Huang, Kai-Wen

    2015-11-01

    In contrast to convex nano-pattern sapphire substrates (NPSS), which are frequently used to fabricate high-quality nitride-based light-emitting diodes (LEDs), concave NPSS have been paid relatively less attention. In this study, a concave NPSS was fabricated, and its nitride epitaxial growth process was evaluated in a step by step manner. A SiO2 layer was used to avoid nucleation over the sidewall and bottom of the nano-patterns to reduce dislocation reformation. Traditional LED structures were grown on the NPSS layer to determine its influence on device performance. X-ray diffraction, etched pit density, inverse leakage current, and internal quantum efficiency (IQE) results showed that dislocations and non-radiative recombination centers are reduced by the NPSS constructed with a SiO2 blocking layer. An IQE twice that on a planar substrate was also achieved; such a high IQE significantly enhanced the external quantum efficiency of the resultant device. Taken together, the results demonstrate that the SiO2 blocking layer proposed in this work can enhance the performance of LEDs.

  4. Evidence-based clinical update: Which local anesthetic drug for pediatric caudal block provides optimal efficacy with the fewest side effects?

    PubMed

    Dobereiner, Elisabeth F A; Cox, Robin G; Ewen, Alastair; Lardner, David R

    2010-12-01

    The purpose of this evidence-based clinical update is to identify the best evidence when selecting a long-acting local anesthetic agent for single-shot pediatric caudal anesthesia in children. A structured literature search was conducted using PubMed and Medline (OVID) using the terms "caudal" and combinations of at least two of "bupivacaine", "ropivacaine", and "levobupivacaine". The search limits included "randomized controlled trials" (RCTs), "meta-analysis", "evidence-based reviews" or "reviews", "human", and "all child: 0-18 yr". Seventeen RCTs were identified that concerned single-shot pediatric caudal anesthesia with at least two of the three drugs in question. Data were extracted for the areas of clinical efficacy and side effects. Study findings were assigned levels of evidence, and grades of recommendation were made according to Centre for Evidence-Based Medicine criteria. The three drugs investigated were found to be equivalent in terms of efficacy. Evidence showed bupivacaine with the highest incidence of motor block and ropivacaine with the lowest. Adverse effects were rare and unrelated to the choice of drug. There were no serious adverse events. None of the three agents was shown to be superior in terms of efficacy. Bupivacaine is preferred if motor block is desired, ropivacaine is preferred if motor block is to be minimized. Adverse effects in human studies are rare, mild, and unrelated to the choice of drug. Despite encountering the absence of serious adverse events in each of the studies reviewed, it is noted that animal studies suggest a safer profile with ropivacaine or levobupivacaine than with bupivacaine.

  5. Tick Talk: Block Tick Bites and Lyme Disease

    MedlinePlus

    ... Subscribe May 2014 Print this issue Tick Talk Block Tick Bites and Lyme Disease En español Send ... Health Researchers Examine the Structure of Zika Virus Block the Buzzing, Bites, and Bumps Wise Choices To ...

  6. An object-oriented approach for parallel self adaptive mesh refinement on block structured grids

    NASA Technical Reports Server (NTRS)

    Lemke, Max; Witsch, Kristian; Quinlan, Daniel

    1993-01-01

    Self-adaptive mesh refinement dynamically matches the computational demands of a solver for partial differential equations to the activity in the application's domain. In this paper we present two C++ class libraries, P++ and AMR++, which significantly simplify the development of sophisticated adaptive mesh refinement codes on (massively) parallel distributed memory architectures. The development is based on our previous research in this area. The C++ class libraries provide abstractions to separate the issues of developing parallel adaptive mesh refinement applications into those of parallelism, abstracted by P++, and adaptive mesh refinement, abstracted by AMR++. P++ is a parallel array class library to permit efficient development of architecture independent codes for structured grid applications, and AMR++ provides support for self-adaptive mesh refinement on block-structured grids of rectangular non-overlapping blocks. Using these libraries, the application programmers' work is greatly simplified to primarily specifying the serial single grid application and obtaining the parallel and self-adaptive mesh refinement code with minimal effort. Initial results for simple singular perturbation problems solved by self-adaptive multilevel techniques (FAC, AFAC), being implemented on the basis of prototypes of the P++/AMR++ environment, are presented. Singular perturbation problems frequently arise in large applications, e.g. in the area of computational fluid dynamics. They usually have solutions with layers which require adaptive mesh refinement and fast basic solvers in order to be resolved efficiently.

  7. Kriging analysis of mean annual precipitation, Powder River Basin, Montana and Wyoming

    USGS Publications Warehouse

    Karlinger, M.R.; Skrivan, James A.

    1981-01-01

    Kriging is a statistical estimation technique for regionalized variables which exhibit an autocorrelation structure. Such structure can be described by a semi-variogram of the observed data. The kriging estimate at any point is a weighted average of the data, where the weights are determined using the semi-variogram and an assumed drift, or lack of drift, in the data. Block, or areal, estimates can also be calculated. The kriging algorithm, based on unbiased and minimum-variance estimates, involves a linear system of equations to calculate the weights. Kriging variances can then be used to give confidence intervals of the resulting estimates. Mean annual precipitation in the Powder River basin, Montana and Wyoming, is an important variable when considering restoration of coal-strip-mining lands of the region. Two kriging analyses involving data at 60 stations were made--one assuming no drift in precipitation, and one a partial quadratic drift simulating orographic effects. Contour maps of estimates of mean annual precipitation were similar for both analyses, as were the corresponding contours of kriging variances. Block estimates of mean annual precipitation were made for two subbasins. Runoff estimates were 1-2 percent of the kriged block estimates. (USGS)

  8. Peptide self-assembly: thermodynamics and kinetics.

    PubMed

    Wang, Juan; Liu, Kai; Xing, Ruirui; Yan, Xuehai

    2016-10-21

    Self-assembling systems play a significant role in physiological functions and have therefore attracted tremendous attention due to their great potential for applications in energy, biomedicine and nanotechnology. Peptides, consisting of amino acids, are among the most popular building blocks and programmable molecular motifs. Nanostructures and materials assembled using peptides exhibit important potential for green-life new technology and biomedical applications mostly because of their bio-friendliness and reversibility. The formation of these ordered nanostructures pertains to the synergistic effect of various intermolecular non-covalent interactions, including hydrogen-bonding, π-π stacking, electrostatic, hydrophobic, and van der Waals interactions. Therefore, the self-assembly process is mainly driven by thermodynamics; however, kinetics is also a critical factor in structural modulation and function integration. In this review, we focus on the influence of thermodynamic and kinetic factors on structural assembly and regulation based on different types of peptide building blocks, including aromatic dipeptides, amphiphilic peptides, polypeptides, and amyloid-relevant peptides.

  9. Multivariable frequency domain identification via 2-norm minimization

    NASA Technical Reports Server (NTRS)

    Bayard, David S.

    1992-01-01

    The author develops a computational approach to multivariable frequency domain identification, based on 2-norm minimization. In particular, a Gauss-Newton (GN) iteration is developed to minimize the 2-norm of the error between frequency domain data and a matrix fraction transfer function estimate. To improve the global performance of the optimization algorithm, the GN iteration is initialized using the solution to a particular sequentially reweighted least squares problem, denoted as the SK iteration. The least squares problems which arise from both the SK and GN iterations are shown to involve sparse matrices with identical block structure. A sparse matrix QR factorization method is developed to exploit the special block structure, and to efficiently compute the least squares solution. A numerical example involving the identification of a multiple-input multiple-output (MIMO) plant having 286 unknown parameters is given to illustrate the effectiveness of the algorithm.

  10. Thiazoloisoindigo: a Building Block that Merges the Merits of Thienoisoindigo and Diazaisoindigo for Conjugated Polymers.

    PubMed

    Wan, Xiaobo; Li, Chenchen; Wang, Xiao; Hio-Ieng, Un; Peng, Jiawei; Lan, Zhenggang; Cai, Mian; Pei, Jian; Wang, Jieyu

    2018-04-24

    Thiazoloisoindigo, a novel structural variation of isoindigo, is for the first time utilized to synthesize conjugated polymers. Polymer based on thiazoloisoindigo merges the advantages of the one based on thienoisoindigo and diazaisoindigo: It not only exhibits a greatly red shifted UV-vis absorption to the near-infrared region due to its strong tendency to form quinoidal structures, similar to that based on thienoisoindigo, but also shows excellent ambipolar mobility (hole 3.93 and electron 1.07 cm2 V-1 s-1, respectively) in organic field-effect transistors (OFETs), superior than that based on diazaisoindigo, showing the strong electron-withdrawing capability of thiazoloisoindigo. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Assembly of RNA nanostructures on supported lipid bilayers

    NASA Astrophysics Data System (ADS)

    Dabkowska, Aleksandra P.; Michanek, Agnes; Jaeger, Luc; Rabe, Michael; Chworos, Arkadiusz; Höök, Fredrik; Nylander, Tommy; Sparr, Emma

    2014-12-01

    The assembly of nucleic acid nanostructures with controlled size and shape has large impact in the fields of nanotechnology, nanomedicine and synthetic biology. The directed arrangement of nano-structures at interfaces is important for many applications. In spite of this, the use of laterally mobile lipid bilayers to control RNA three-dimensional nanostructure formation on surfaces remains largely unexplored. Here, we direct the self-assembly of RNA building blocks into three-dimensional structures of RNA on fluid lipid bilayers composed of cationic 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) or mixtures of zwitterionic 1,2-dioleoyl-sn-glycero-3-phosphatidylcholine (DOPC) and cationic sphingosine. We demonstrate the stepwise supramolecular assembly of discrete building blocks through specific and selective RNA-RNA interactions, based on results from quartz crystal microbalance with dissipation (QCM-D), ellipsometry, fluorescence recovery after photobleaching (FRAP) and total internal reflection fluorescence microscopy (TIRF) experiments. The assembly can be controlled to give a densely packed single layer of RNA polyhedrons at the fluid lipid bilayer surface. We show that assembly of the 3D structure can be modulated by sequence specific interactions, surface charge and changes in the salt composition and concentration. In addition, the tertiary structure of the RNA polyhedron can be controllably switched from an extended structure to one that is dense and compact. The versatile approach to building up three-dimensional structures of RNA does not require modification of the surface or the RNA molecules, and can be used as a bottom-up means of nanofabrication of functionalized bio-mimicking surfaces.The assembly of nucleic acid nanostructures with controlled size and shape has large impact in the fields of nanotechnology, nanomedicine and synthetic biology. The directed arrangement of nano-structures at interfaces is important for many applications. In spite of this, the use of laterally mobile lipid bilayers to control RNA three-dimensional nanostructure formation on surfaces remains largely unexplored. Here, we direct the self-assembly of RNA building blocks into three-dimensional structures of RNA on fluid lipid bilayers composed of cationic 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) or mixtures of zwitterionic 1,2-dioleoyl-sn-glycero-3-phosphatidylcholine (DOPC) and cationic sphingosine. We demonstrate the stepwise supramolecular assembly of discrete building blocks through specific and selective RNA-RNA interactions, based on results from quartz crystal microbalance with dissipation (QCM-D), ellipsometry, fluorescence recovery after photobleaching (FRAP) and total internal reflection fluorescence microscopy (TIRF) experiments. The assembly can be controlled to give a densely packed single layer of RNA polyhedrons at the fluid lipid bilayer surface. We show that assembly of the 3D structure can be modulated by sequence specific interactions, surface charge and changes in the salt composition and concentration. In addition, the tertiary structure of the RNA polyhedron can be controllably switched from an extended structure to one that is dense and compact. The versatile approach to building up three-dimensional structures of RNA does not require modification of the surface or the RNA molecules, and can be used as a bottom-up means of nanofabrication of functionalized bio-mimicking surfaces. Electronic supplementary information (ESI) available: Table with sequences of tRNA units used in this study; schematic structures of the RNA polyhedron and its building blocks; gel electrophoresis characterization of the RNA polyhedron and squares; AFM characterization of RNA tectosquare; schematic structures of RNA-9 and RNA-10 and their association with lipid bilayers; QCM-D frequency and dissipation data (as function of time) for adsorption of RNA polyhedrons, RNA squares and RNA9-10 TIRF images of RNA with Gelstar after photobleaching with analysis; Correlation plot in change of shear viscosity for TS3 and TO3-4 models for the stoichiometry of TS; QCM-D dissipation data for the sequential experiment in Fig. 5a; QCM-D and for the assembly of building blocks at the bilayer scaffold at varying bulk concentrations; QCM-D of adsorption of TS3. See DOI: 10.1039/c4nr05968a

  12. Rapid self-assembly of block copolymers to photonic crystals

    DOEpatents

    Xia, Yan; Sveinbjornsson, Benjamin R; Grubbs, Robert H; Weitekamp, Raymond; Miyake, Garret M; Atwater, Harry A; Piunova, Victoria; Daeffler, Christopher Scot; Hong, Sung Woo; Gu, Weiyin; Russell, Thomas P.

    2016-07-05

    The invention provides a class of copolymers having useful properties, including brush block copolymers, wedge-type block copolymers and hybrid wedge and polymer block copolymers. In an embodiment, for example, block copolymers of the invention incorporate chemically different blocks comprising polymer size chain groups and/or wedge groups that significantly inhibit chain entanglement, thereby enhancing molecular self-assembly processes for generating a range of supramolecular structures, such as periodic nanostructures and microstructures. The present invention also provides useful methods of making and using copolymers, including block copolymers.

  13. Structure-Based Low-Rank Model With Graph Nuclear Norm Regularization for Noise Removal.

    PubMed

    Ge, Qi; Jing, Xiao-Yuan; Wu, Fei; Wei, Zhi-Hui; Xiao, Liang; Shao, Wen-Ze; Yue, Dong; Li, Hai-Bo

    2017-07-01

    Nonlocal image representation methods, including group-based sparse coding and block-matching 3-D filtering, have shown their great performance in application to low-level tasks. The nonlocal prior is extracted from each group consisting of patches with similar intensities. Grouping patches based on intensity similarity, however, gives rise to disturbance and inaccuracy in estimation of the true images. To address this problem, we propose a structure-based low-rank model with graph nuclear norm regularization. We exploit the local manifold structure inside a patch and group the patches by the distance metric of manifold structure. With the manifold structure information, a graph nuclear norm regularization is established and incorporated into a low-rank approximation model. We then prove that the graph-based regularization is equivalent to a weighted nuclear norm and the proposed model can be solved by a weighted singular-value thresholding algorithm. Extensive experiments on additive white Gaussian noise removal and mixed noise removal demonstrate that the proposed method achieves a better performance than several state-of-the-art algorithms.

  14. Adaptive mesh refinement and load balancing based on multi-level block-structured Cartesian mesh

    NASA Astrophysics Data System (ADS)

    Misaka, Takashi; Sasaki, Daisuke; Obayashi, Shigeru

    2017-11-01

    We developed a framework for a distributed-memory parallel computer that enables dynamic data management for adaptive mesh refinement and load balancing. We employed simple data structure of the building cube method (BCM) where a computational domain is divided into multi-level cubic domains and each cube has the same number of grid points inside, realising a multi-level block-structured Cartesian mesh. Solution adaptive mesh refinement, which works efficiently with the help of the dynamic load balancing, was implemented by dividing cubes based on mesh refinement criteria. The framework was investigated with the Laplace equation in terms of adaptive mesh refinement, load balancing and the parallel efficiency. It was then applied to the incompressible Navier-Stokes equations to simulate a turbulent flow around a sphere. We considered wall-adaptive cube refinement where a non-dimensional wall distance y+ near the sphere is used for a criterion of mesh refinement. The result showed the load imbalance due to y+ adaptive mesh refinement was corrected by the present approach. To utilise the BCM framework more effectively, we also tested a cube-wise algorithm switching where an explicit and implicit time integration schemes are switched depending on the local Courant-Friedrichs-Lewy (CFL) condition in each cube.

  15. The Impact of Individual Differences, Types of Model and Social Settings on Block Building Performance among Chinese Preschoolers

    PubMed Central

    Tian, Mi; Deng, Zhu; Meng, Zhaokun; Li, Rui; Zhang, Zhiyi; Qi, Wenhui; Wang, Rui; Yin, Tingting; Ji, Menghui

    2018-01-01

    Children’s block building performances are used as indicators of other abilities in multiple domains. In the current study, we examined individual differences, types of model and social settings as influences on children’s block building performance. Chinese preschoolers (N = 180) participated in a block building activity in a natural setting, and performance was assessed with multiple measures in order to identify a range of specific skills. Using scores generated across these measures, three dependent variables were analyzed: block building skills, structural balance and structural features. An overall MANOVA showed that there were significant main effects of gender and grade level across most measures. Types of model showed no significant effect in children’s block building. There was a significant main effect of social settings on structural features, with the best performance in the 5-member group, followed by individual and then the 10-member block building. These findings suggest that boys performed better than girls in block building activity. Block building performance increased significantly from 1st to 2nd year of preschool, but not from second to third. The preschoolers created more representational constructions when presented with a model made of wooden rather than with a picture. There was partial evidence that children performed better when working with peers in a small group than when working alone or working in a large group. It is suggested that future study should examine other modalities rather than the visual one, diversify the samples and adopt a longitudinal investigation. PMID:29441031

  16. Evidence of formation of site-selective inclusion complexation between beta-cyclodextrin and poly(ethylene oxide)-block-poly(propylene oxide)- block-poly(ethylene oxide) copolymers.

    PubMed

    Tsai, Chi-Chun; Zhang, Wen-Bin; Wang, Chien-Lung; Van Horn, Ryan M; Graham, Matthew J; Huang, Jing; Chen, Yongming; Guo, Mingming; Cheng, Stephen Z D

    2010-05-28

    A series of inclusion complexes of poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) (PEO-b-PPO-b-PEO) with beta-cyclodextrin (beta-CD) was prepared. Their formation, structure, and dynamics were investigated by solution two-dimensional rotating-frame Overhauser effect spectroscopy (2D ROESY) and one-dimensional (1D) and 2D solid-state (13)C NMR. The inclusion complexes between the PEO-b-PPO-b-PEO copolymers and the beta-CDs were formed in aqueous solution and detected by 2D ROESY. The high efficiency of cross polarization and spin diffusion experiments in (13)C solid-state NMR showed that the mobility of the PPO blocks dramatically decreases after beta-CD complexation, indicating that they are selectively incorporated onto the PPO blocks. The hydrophobic cavities of beta-CD restrict the PPO block mobility, which is evidence of the formation of inclusion complexes in the solid state. The 2D wide-line separation NMR experiments suggested that beta-CDs only thread onto the PPO blocks while forming the inclusion complexes. The stoichiometry of inclusion complexes was studied using (1)H NMR, and a 3:1 (PO unit to beta-CD) was found for all inclusion complexes, which indicated that the number of threaded beta-CDs was only dependent on the molecular weight of the PPO blocks. 1D wide angle x-ray diffraction studies demonstrated that the beta-CD in the inclusion complex formed a channel-like structure that is different from the pure beta-CD crystal structure.

  17. Evidence of formation of site-selective inclusion complexation between β-cyclodextrin and poly(ethylene oxide)-block-poly(propylene oxide)- block-poly(ethylene oxide) copolymers

    NASA Astrophysics Data System (ADS)

    Tsai, Chi-Chun; Zhang, Wen-Bin; Wang, Chien-Lung; Van Horn, Ryan M.; Graham, Matthew J.; Huang, Jing; Chen, Yongming; Guo, Mingming; Cheng, Stephen Z. D.

    2010-05-01

    A series of inclusion complexes of poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) (PEO-b-PPO-b-PEO) with β-cyclodextrin (β-CD) was prepared. Their formation, structure, and dynamics were investigated by solution two-dimensional rotating-frame Overhauser effect spectroscopy (2D ROESY) and one-dimensional (1D) and 2D solid-state C13 NMR. The inclusion complexes between the PEO-b-PPO-b-PEO copolymers and the β-CDs were formed in aqueous solution and detected by 2D ROESY. The high efficiency of cross polarization and spin diffusion experiments in C13 solid-state NMR showed that the mobility of the PPO blocks dramatically decreases after β-CD complexation, indicating that they are selectively incorporated onto the PPO blocks. The hydrophobic cavities of β-CD restrict the PPO block mobility, which is evidence of the formation of inclusion complexes in the solid state. The 2D wide-line separation NMR experiments suggested that β-CDs only thread onto the PPO blocks while forming the inclusion complexes. The stoichiometry of inclusion complexes was studied using H1 NMR, and a 3:1 (PO unit to β-CD) was found for all inclusion complexes, which indicated that the number of threaded β-CDs was only dependent on the molecular weight of the PPO blocks. 1D wide angle x-ray diffraction studies demonstrated that the β-CD in the inclusion complex formed a channel-like structure that is different from the pure β-CD crystal structure.

  18. SWT voting-based color reduction for text detection in natural scene images

    NASA Astrophysics Data System (ADS)

    Ikica, Andrej; Peer, Peter

    2013-12-01

    In this article, we propose a novel stroke width transform (SWT) voting-based color reduction method for detecting text in natural scene images. Unlike other text detection approaches that mostly rely on either text structure or color, the proposed method combines both by supervising text-oriented color reduction process with additional SWT information. SWT pixels mapped to color space vote in favor of the color they correspond to. Colors receiving high SWT vote most likely belong to text areas and are blocked from being mean-shifted away. Literature does not explicitly address SWT search direction issue; thus, we propose an adaptive sub-block method for determining correct SWT direction. Both SWT voting-based color reduction and SWT direction determination methods are evaluated on binary (text/non-text) images obtained from a challenging Computer Vision Lab optical character recognition database. SWT voting-based color reduction method outperforms the state-of-the-art text-oriented color reduction approach.

  19. Performance Evaluation of Frequency Transform Based Block Classification of Compound Image Segmentation Techniques

    NASA Astrophysics Data System (ADS)

    Selwyn, Ebenezer Juliet; Florinabel, D. Jemi

    2018-04-01

    Compound image segmentation plays a vital role in the compression of computer screen images. Computer screen images are images which are mixed with textual, graphical, or pictorial contents. In this paper, we present a comparison of two transform based block classification of compound images based on metrics like speed of classification, precision and recall rate. Block based classification approaches normally divide the compound images into fixed size blocks of non-overlapping in nature. Then frequency transform like Discrete Cosine Transform (DCT) and Discrete Wavelet Transform (DWT) are applied over each block. Mean and standard deviation are computed for each 8 × 8 block and are used as features set to classify the compound images into text/graphics and picture/background block. The classification accuracy of block classification based segmentation techniques are measured by evaluation metrics like precision and recall rate. Compound images of smooth background and complex background images containing text of varying size, colour and orientation are considered for testing. Experimental evidence shows that the DWT based segmentation provides significant improvement in recall rate and precision rate approximately 2.3% than DCT based segmentation with an increase in block classification time for both smooth and complex background images.

  20. Hierarchical structure and dynamics of oligocarbonate-functionalized PEG block copolymer gels

    NASA Astrophysics Data System (ADS)

    Prabhu, Vivek; Wei, Guangmin; Ali, Samim; Venkataraman, Shrinivas; Yang, Yi Yan; Hedrick, James

    Hierarchical, self-assembled block copolymers in aqueous solutions provide advanced materials for biomaterial applications. Recent advancements in the synthesis of aliphatic polycarbonates have shown nontraditional micellar and hierarchical structures driven by the supramolecular assembly of the carbonate block functionality that includes cholesterol, vitamin D, and fluorene. This presentation shall describe the supramolecular assembly structure and dynamics observed by static and dynamic light scattering, small-angle neutron scattering and transmission electron microscopy in a model pi-pi stacking driven fluorene system. The combination of real-space and reciprocal space methods to develop appropriate models that quantify the structure from the micelle to transient gel network will be discussed. 1) Biomedical Research Council, Agency for Science, Technology and Research, Singapore, 2) NIST Materials Genome Initiative.

  1. Thermally Induced Structural Evolution and Performance of Mesoporous Block Copolymer-Directed Alumina Perovskite Solar Cells

    PubMed Central

    2015-01-01

    Structure control in solution-processed hybrid perovskites is crucial to design and fabricate highly efficient solar cells. Here, we utilize in situ grazing incidence wide-angle X-ray scattering and scanning electron microscopy to investigate the structural evolution and film morphologies of methylammonium lead tri-iodide/chloride (CH3NH3PbI3–xClx) in mesoporous block copolymer derived alumina superstructures during thermal annealing. We show the CH3NH3PbI3–xClx material evolution to be characterized by three distinct structures: a crystalline precursor structure not described previously, a 3D perovskite structure, and a mixture of compounds resulting from degradation. Finally, we demonstrate how understanding the processing parameters provides the foundation needed for optimal perovskite film morphology and coverage, leading to enhanced block copolymer-directed perovskite solar cell performance. PMID:24684494

  2. The Ettention software package.

    PubMed

    Dahmen, Tim; Marsalek, Lukas; Marniok, Nico; Turoňová, Beata; Bogachev, Sviatoslav; Trampert, Patrick; Nickels, Stefan; Slusallek, Philipp

    2016-02-01

    We present a novel software package for the problem "reconstruction from projections" in electron microscopy. The Ettention framework consists of a set of modular building-blocks for tomographic reconstruction algorithms. The well-known block iterative reconstruction method based on Kaczmarz algorithm is implemented using these building-blocks, including adaptations specific to electron tomography. Ettention simultaneously features (1) a modular, object-oriented software design, (2) optimized access to high-performance computing (HPC) platforms such as graphic processing units (GPU) or many-core architectures like Xeon Phi, and (3) accessibility to microscopy end-users via integration in the IMOD package and eTomo user interface. We also provide developers with a clean and well-structured application programming interface (API) that allows for extending the software easily and thus makes it an ideal platform for algorithmic research while hiding most of the technical details of high-performance computing. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Charged triblock copolymer self-assembly into charged micelles

    NASA Astrophysics Data System (ADS)

    Chen, Yingchao; Zhang, Ke; Zhu, Jiahua; Wooley, Karen; Pochan, Darrin; Department of Material Science; Engineering University of Delaware Team; Department of Chemistry Texas A&M University Collaboration

    2011-03-01

    Micelles were formed through the self-assembly of amphiphlic block copolymer poly(acrylic acid)-block-poly(methyl acrylate)-block-polystyrene (PAA-PMA-PS). ~Importantly, the polymer is complexed with diamine molecules in pure THF solution prior to water titration solvent processing-a critical aspect in the control of final micelle geometry. The addition of diamine triggers acid-base complexation ~between the carboxylic acid PAA side chains and amines. ~Remarkably uniform spheres were found to form close-packed patterns when forced into dried films and thin, solvated films when an excess of amine was used in the polymer assembly process. Surface properties and structural features of these hexagonal-packed spherical micelles with charged corona have been explored by various characterization methods including Transmission Electron Microscopy (TEM), cryogenic TEM, z-potential analysis and Dynamic Light Scattering. The forming mechanism for this pattern and morphology changes against external stimulate such as salt will be discussed.

  4. Using Blocked Fractional Factorial Designs to Construct Discrete Choice Experiments for Health Care Studies

    PubMed Central

    Jaynes, Jessica; Wong, Weng Kee; Xu, Hongquan

    2016-01-01

    Discrete choice experiments (DCEs) are increasingly used for studying and quantifying subjects preferences in a wide variety of health care applications. They provide a rich source of data to assess real-life decision making processes, which involve trade-offs between desirable characteristics pertaining to health and health care, and identification of key attributes affecting health care. The choice of the design for a DCE is critical because it determines which attributes’ effects and their interactions are identifiable. We apply blocked fractional factorial designs to construct DCEs and address some identification issues by utilizing the known structure of blocked fractional factorial designs. Our design techniques can be applied to several situations including DCEs where attributes have different number of levels. We demonstrate our design methodology using two health care studies to evaluate (1) asthma patients’ preferences for symptom-based outcome measures, and (2) patient preference for breast screening services. PMID:26823156

  5. Design, synthesis, and characterization of new phosphazene related materials, and study the structure property correlations

    NASA Astrophysics Data System (ADS)

    Tian, Zhicheng

    The work described in this thesis is divided into three major parts, and all of which involve the exploration of the chemistry of polyphosphazenes. The first part (chapters 2 and 3) of my research is synthesis and study polyphoshazenes for biomedical applications, including polymer drug conjugates and injectable hydrogels for drug or biomolecule delivery. The second part (chapters 4 and 5) focuses on the synthesis of several organic/inorganic hybrid polymeric structures, such as diblock, star, brush and palm tree copolymers using living cationic polymerization and atom transfer radical polymerization techniques. The last part (chapters 6 and 7) is about exploratory synthesis of new polymeric structures with fluorinated side groups or cycloaliphatic side groups, and the study of new structure property relationships. Chapter 1 is an outline of the fundamental concepts for polymeric materials, as such the history, important definitions, and some introductory material for to polymer chemistry and physics. The chemistry and applications of phopshazenes is also briefly described. Chapter 2 is a description of the design, synthesis, and characterization of development of a new class of polymer drug conjugate materials based on biodegradable polyphosphazenes and antibiotics. Poly(dichlorophosphazene), synthesized by a thermal ring opening polymerization, was reacted with up to 25 mol% of ciprofloxacin or norfloxacin and three different amino acid esters (glycine, alanine, or phenylalanine) as cosubstituents via macromolecular substitutions. Nano/microfibers of several selected polymers were prepared by an electrospinning technique. Chapter 3 is concerned with the development of a class of injectable and biodegradable hydrogels based on water-soluble poly(organophosphazenes) containing oligo(ethylene glycol) methyl ethers and glycine ethyl esters. The hydrogels can be obtained by mixing alpha-cyclodextrin aqueous solution and poly(organophosphazenes) aqueous solution in various gelation rates depending on the polymer structures and the concentrations. The rheological measurements of the supramolecular hydrogels indicate a fast gelation process and flowable character under a large stain. Chapter 4 outlines the preparation of a number of amphiphilic diblock copolymers based on poly[bis(trifluoroethoxy)phosphazene] (TFE) as the hydrophobic block and poly(dimethylaminoethylmethacrylate) (PDMAEMA) as the hydrophilic block. The TFE block was synthesized first by the controlled living cationic polymerization of a phosphoranimine, followed by replacement of all the chlorine atoms using sodium trifluoroethoxide. To allow for the growth of the PDMAEMA block, 3-azidopropyl-2-bromo-2-methylpropanoate, an atom transfer radical polymerization (ATRP) initiator, was grafted onto the endcap of the TFE block via the 'click' reaction followed by the ATRP of 2-(dimethylamino)ethyl methacrylate (DMAEMA). Chapter 5 is a report on the design and assembly of polyphosphazene materials based on the non-covalent "host--guest" interactions either at the terminus of the polymeric main-chains or the pendant side-chains. The supramolecular interaction at the main chain terminus was used to produce amphiphilic palm-tree like pseudo-block copolymers via host-guest interactions between an adamantane end-functionalized polyphosphazene and a 4-armed beta-cyclodextrin (beta-CD) initiated poly[poly(ethylene glycol) methyl ether methacylate] branched-star type polymer. The formation of micelles of the obtained amphiphiles was analyzed by fluorescence technique, dynamic light scattering, transmission electron microscopy, and atomic force microscopy. Chapter 6 is an investigation of the influence of bulky fluoroalkoxy side groups on the properties of polyphosphazenes. A new series of mixed-substituent high polymeric poly(fluoroalkoxyphosphazenes) containing trifluoroethoxy and branched fluoroalkoxy side groups was synthesized and characterized by NMR and GPC methods. These polymers contained 19--29 mol% of di-branched hexafluoropropoxy groups or 4mol% of tri-branched tert-perfluorobutoxy groups, which serve as regio-irregularities to reduce the macromolecular microcrystallinity. The structure--property correlations of the polymers were then analyzed and interpreted by several techniques: specifically by the thermal behavior by DSC and TGA methods, the crystallinity by wide-angle X-ray diffraction, and the surface hydrophobicity/oleophobicity by contact angle measurements. (Abstract shortened by UMI.). Chapter 7 is an outline of the exploratory synthesis of a new series of phosphazene model cyclic trimers and single- and mixed- substituent high polymers containing cyclic aliphatic rings, --CnH2n-1 (where n = 4--8). The cylco-aliphatic side group containing phosphazenes expand the structural and property boundaries of phosphazene chemistry, and suggest additional approaches for studying slow macromolecular substitution reactions and substituent exchange reactions.

  6. Balancing Performance and Sustainability in Next-Generation PMR Technologies for OMC Structures (Briefing Charts)

    DTIC Science & Technology

    2016-05-26

    Amines Purity(1H-NMR) Amine/ aldehyde ratio Temp. Time DFDA 99% 1:2 25 oC 70 min CH3-DFDA 98% 1:2 40 oC 70 min DM-DFDA 97% 1:2 40 oC 24 h Benzyl- DFDA...are combinations of phenyl and furfural building blocks.  A wide variety of bio-based aldehydes can be used to prepare furan based amines . Result

  7. Structural DNA Nanotechnology: State of the Art and Future Perspective

    PubMed Central

    2015-01-01

    Over the past three decades DNA has emerged as an exceptional molecular building block for nanoconstruction due to its predictable conformation and programmable intra- and intermolecular Watson–Crick base-pairing interactions. A variety of convenient design rules and reliable assembly methods have been developed to engineer DNA nanostructures of increasing complexity. The ability to create designer DNA architectures with accurate spatial control has allowed researchers to explore novel applications in many directions, such as directed material assembly, structural biology, biocatalysis, DNA computing, nanorobotics, disease diagnosis, and drug delivery. This Perspective discusses the state of the art in the field of structural DNA nanotechnology and presents some of the challenges and opportunities that exist in DNA-based molecular design and programming. PMID:25029570

  8. 4. "TEST STAND NO. 13, CONCRETE STRUCTURAL PLAN AND ELEVATION." ...

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

    4. "TEST STAND NO. 1-3, CONCRETE STRUCTURAL PLAN AND ELEVATION." Specifications No. OC11-50-10; Drawing No. 60-09-06; no sheet number within title block. D.O. SERIES 1109/12 REV. E. Stamped: RECORD DRAWING - AS CONSTRUCTED. Below stamp: Contract DA-04-353 Eng. 177, Rev. E; Date: 17 Dec. 1951. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-3, Test Area 1-115, northwest end of Saturn Boulevard, Boron, Kern County, CA

  9. Studies of Learning and Self-Contained Educational Systems, 1973-1976

    DTIC Science & Technology

    1976-03-01

    ISTKIW WORDS fCondnu» on reverse aide // neceeeary ««’ ’-dtntlly by block numb«; Leirning, teaching, memory, tutorial instruction. 20. AB ^RACT...poorly acquired or because the learner might have missed exposi -e to that part of the material, then the rest of the structure is weakened and may...War in the computer data bsnt, including the causal structure of the actions during the war. We are ab ]^ to use the data base to interact with a

  10. 11. "TEST STANDS NOS. 11, 13, & 15; CONCRETE STRUCTURAL ...

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

    11. "TEST STANDS NOS. 1-1, 1-3, & 1-5; CONCRETE STRUCTURAL SECTIONS AND DETAILS." Specifications No. OC12-50-10; Drawing No. 60-09-04; no sheet number within title block. D.O. SERIES 1109/15, Rev. E. Stamped: RECORD DRAWING - AS CONSTRUCTED. Below stamp: Contract DA-04353 Eng. 177, Rev. E; Date: 21 Dec. 1951. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-5, Test Area 1-115, northwest end of Saturn Boulevard, Boron, Kern County, CA

  11. 13. "TEST STANDS NOS. 11, 13, & 15; CONCRETE STRUCTURAL ...

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

    13. "TEST STANDS NOS. 1-1, 1-3, & 1-5; CONCRETE STRUCTURAL SECTIONS AND DETAILS." Specifications No. OC12-50-10; Drawing No. 60-09-04; no sheet number within title block. D.O. SERIES 1109/18, Rev. D. Stamped: RECORD DRAWING - AS CONSTRUCTED. Below stamp: Contract DA-04353 Eng. 177, Rev. D, no change; Date: 18 Dec. 1951. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-5, Test Area 1-115, northwest end of Saturn Boulevard, Boron, Kern County, CA

  12. 15. "TEST STANDS NOS. 11, 13, & 15; STRUCTURAL STEEL; ...

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

    15. "TEST STANDS NOS. 1-1, 1-3, & 1-5; STRUCTURAL STEEL; PLAN & DETAILS." Specifications No. ENG 04-353-50-10; Drawing No. 60-09-04; no sheet number within title block. D.O. SERIES 1109/34, Rev. A. Stamped: RECORD DRAWING - AS CONSTRUCTED. Below stamp: Contract DA-04353 Eng. 177, Rev. A, no change; Date: 21 Dec. 1951. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-5, Test Area 1-115, northwest end of Saturn Boulevard, Boron, Kern County, CA

  13. 9. "TEST STANDS NOS. 11, 13, & 15; CONCRETE STRUCTURAL ...

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

    9. "TEST STANDS NOS. 1-1, 1-3, & 1-5; CONCRETE STRUCTURAL SECTIONS AND DETAILS." Specifications No. ENG 04-35350-10; Drawing No. 60-09-04; no sheet number within title block. D.O. SERIES 1109/13. Stamped: RECORD DRAWING - AS CONSTRUCTED. Below stamp: Contract DA-04353 Eng. 177, no change; Date: 17 Dec. 1951. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-5, Test Area 1-115, northwest end of Saturn Boulevard, Boron, Kern County, CA

  14. 10. "TEST STANDS NOS. 11, 13, & 15; CONCRETE STRUCTURAL ...

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

    10. "TEST STANDS NOS. 1-1, 1-3, & 1-5; CONCRETE STRUCTURAL SECTIONS AND DETAILS." Specifications No. OC12-50-10; Drawing No. 60-09-04; no sheet number within title block. D.O. SERIES 1109/14, Rev. B. Stamped: RECORD DRAWING - AS CONSTRUCTED. Below stamp: Contract DA-04353 Eng. 177, Rev. B; Date: 21 Dec. 1951. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-5, Test Area 1-115, northwest end of Saturn Boulevard, Boron, Kern County, CA

  15. 16. "TEST STANDS NOS. 11, 13, & 15; STRUCTURAL STEEL; ...

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

    16. "TEST STANDS NOS. 1-1, 1-3, & 1-5; STRUCTURAL STEEL; ELEVATIONS AND SECTIONS." Specifications No. ENG 04353-50-10; Drawing No. 60-09-04; no sheet number within title block. D.O. SERIES 1109/35, Rev. A. Stamped: RECORD DRAWING - AS CONSTRUCTED. Below stamp: Contract DA-04-353 Eng. 177, Rev. A; Date: 29 Dec. 1951. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-5, Test Area 1-115, northwest end of Saturn Boulevard, Boron, Kern County, CA

  16. 12. "TEST STANDS NOS. 11, 13, & 15; CONCRETE STRUCTURAL ...

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

    12. "TEST STANDS NOS. 1-1, 1-3, & 1-5; CONCRETE STRUCTURAL SECTIONS AND DETAILS." Specifications No. OC12-50-10; Drawing No. 60-09-06; no sheet number within title block. D.O. SERIES 1109/16, Rev. E. Stamped: RECORD DRAWING - AS CONSTRUCTED. Below stamp: Contract DA-04353 Eng. 177, Rev. E; Date: 26 Dec. 1951. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-5, Test Area 1-115, northwest end of Saturn Boulevard, Boron, Kern County, CA

  17. Neurocomputing

    NASA Technical Reports Server (NTRS)

    Hecht-Nielsen, Robert

    1990-01-01

    The present work is intended to give technologists, research scientists, and mathematicians a graduate-level overview of the field of neurocomputing. After exploring the relationship of this field to general neuroscience, attention is given to neural network building blocks, the self-adaptation equations of learning laws, the data-transformation structures of associative networks, and the multilayer data-transformation structures of mapping networks. Also treated are the neurocomputing frontiers of spatiotemporal, stochastic, and hierarchical networks, 'neurosoftware', the creation of neural network-based computers, and neurocomputing applications in sensor processing, control, and data analysis.

  18. Highly ordered gold nanotubes using thiols at a cleavable block copolymer interface.

    PubMed

    Ryu, Ja-Hyoung; Park, Soojin; Kim, Bokyung; Klaikherd, Akamol; Russell, Thomas P; Thayumanavan, S

    2009-07-29

    We have prepared functionalized nanoporous thin films from a polystyrene-block-polyethylene oxide block copolymer, which was made cleavable due to the intervening disulfide bond. The cleavage reaction of the disulfide bond leaves behind free thiol groups inside the nanopores of polystyrene thin film. This nanoporous thin film can be used as a template for generating gold nanoring structures. This strategy can provide a facile method to form a highly ordered array of biopolymer or metal-polymer composite structures.

  19. 31. Detail of Southeast Light lens and roof structure of ...

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

    31. Detail of Southeast Light lens and roof structure of light gallery, 1985. Taken day after Hurricane Gloria, courtesy of Gerald F. Abbott and Block Island Historical Society. - Block Island Southeast Light, Spring Street & Mohegan Trail at Mohegan Bluffs, New Shoreham, Washington County, RI

  20. Unsymmetric Lanczos model reduction and linear state function observer for flexible structures

    NASA Technical Reports Server (NTRS)

    Su, Tzu-Jeng; Craig, Roy R., Jr.

    1991-01-01

    This report summarizes part of the research work accomplished during the second year of a two-year grant. The research, entitled 'Application of Lanczos Vectors to Control Design of Flexible Structures' concerns various ways to use Lanczos vectors and Krylov vectors to obtain reduced-order mathematical models for use in the dynamic response analyses and in control design studies. This report presents a one-sided, unsymmetric block Lanczos algorithm for model reduction of structural dynamics systems with unsymmetric damping matrix, and a control design procedure based on the theory of linear state function observers to design low-order controllers for flexible structures.

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