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Helical Piles

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https://www.readbyqxmd.com/read/29454064/rna-based-micelles-a-novel-platform-for-paclitaxel-loading-and-delivery
#1
Yi Shu, Hongran Yin, Mehdi Rajabi, Hui Li, Mario Vieweger, Sijin Guo, Dan Shu, Peixuan Guo
RNA can serve as powerful building blocks for bottom-up fabrication of nanostructures for biotechnological and biomedical applications. In addition to current self-assembly strategies utilizing base pairing, motif piling and tertiary interactions, we reported for the first time the formation of RNA based micellar nanoconstruct with a cholesterol molecule conjugated onto one helical end of a branched pRNA three-way junction (3WJ) motif. The resulting amphiphilic RNA micelles consist of a hydrophilic RNA head and a covalently linked hydrophobic lipid tail that can spontaneously assemble in aqueous solution via hydrophobic interaction...
April 28, 2018: Journal of Controlled Release: Official Journal of the Controlled Release Society
https://www.readbyqxmd.com/read/27698424/structure-of-the-neisseria-meningitidis-type-iv-pilus
#2
Subramania Kolappan, Mathieu Coureuil, Xiong Yu, Xavier Nassif, Edward H Egelman, Lisa Craig
Neisseria meningitidis use Type IV pili (T4P) to adhere to endothelial cells and breach the blood brain barrier, causing cause fatal meningitis. T4P are multifunctional polymers of the major pilin protein, which share a conserved hydrophobic N terminus that is a curved extended α-helix, α1, in X-ray crystal structures. Here we report a 1.44 Å crystal structure of the N. meningitidis major pilin PilE and a ∼6 Å cryo-electron microscopy reconstruction of the intact pilus, from which we built an atomic model for the filament...
October 4, 2016: Nature Communications
https://www.readbyqxmd.com/read/27493221/waltzing-route-toward-double-helix-formation-in-cholesteric-shells
#3
Alexandre Darmon, Michael Benzaquen, David Seč, Simon Čopar, Olivier Dauchot, Teresa Lopez-Leon
Liquid crystals, when confined to a spherical shell, offer fascinating possibilities for producing artificial mesoscopic atoms, which could then self-assemble into materials structured at a nanoscale, such as photonic crystals or metamaterials. The spherical curvature of the shell imposes topological constraints in the molecular ordering of the liquid crystal, resulting in the formation of defects. Controlling the number of defects, that is, the shell valency, and their positions, is a key success factor for the realization of those materials...
August 23, 2016: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/27084019/motility-of-electric-cable-bacteria
#4
Jesper Tataru Bjerg, Lars Riis Damgaard, Simon Agner Holm, Andreas Schramm, Lars Peter Nielsen
UNLABELLED: Cable bacteria are filamentous bacteria that electrically couple sulfide oxidation and oxygen reduction at centimeter distances, and observations in sediment environments have suggested that they are motile. By time-lapse microscopy, we found that cable bacteria used gliding motility on surfaces with a highly variable speed of 0.5 ± 0.3 μm s(-1) (mean ± standard deviation) and time between reversals of 155 ± 108 s. They frequently moved forward in loops, and formation of twisted loops revealed helical rotation of the filaments...
July 1, 2016: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/26890916/structure-and-cohesive-energy-of-dipolar-helices
#5
Igor Stanković, Miljan Dašić, René Messina
This paper deals with the investigation of cohesive energy in dipolar helices made up of hard spheres. Such tubular helical structures are ubiquitous objects in biological systems. We observe a complex dependence of cohesive energy on surface packing fraction and dipole moment distribution. As far as single helices are concerned, the lowest cohesive energy is achieved at the highest surface packing fraction. Besides, a striking non-monotonic behavior is reported for the cohesive energy as a function of the surface packing fraction...
March 28, 2016: Soft Matter
https://www.readbyqxmd.com/read/26849249/helical-growth-of-ultrathin-gold-copper-nanowires
#6
Rubén Mendoza-Cruz, Lourdes Bazán-Díaz, J Jesús Velázquez-Salazar, Germán Plascencia-Villa, Daniel Bahena-Uribe, José Reyes-Gasga, David Romeu, Grégory Guisbiers, Raúl Herrera-Becerra, Miguel José-Yacamán
In this work, we report the synthesis and detailed structural characterization of novel helical gold-copper nanowires. The nanowires possess the Boerdijk-Coxeter-Bernal structure, based on the pile up of octahedral, icosahedral, and/or decahedral seeds. They are self-assembled into a coiled manner as individual wires or into a parallel-ordering way as groups of wires. The helical nanowires are ultrathin with a diameter of less than 10 nm and variable length of several micrometers, presenting a high density of twin boundaries and stacking faults...
March 9, 2016: Nano Letters
https://www.readbyqxmd.com/read/25583860/helical-piles-an-innovative-foundation-design-option-for-offshore-wind-turbines
#7
B W Byrne, G T Houlsby
Offshore wind turbines play a key part in the renewable energy strategy in the UK and Europe as well as in other parts of the world (for example, China). The majority of current developments, certainly in UK waters, have taken place in relatively shallow water and close to shore. This limits the scale of the engineering to relatively simple structures, such as those using monopile foundations, and these have been the most common design to date, in UK waters. However, as larger turbines are designed, or they are placed in deeper water, it will be necessary to use multi-footing structures such as tripods or jackets...
February 28, 2015: Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences
https://www.readbyqxmd.com/read/24622954/structure-and-dynamics-of-thylakoids-in-land-plants
#8
REVIEW
Mathias Pribil, Mathias Labs, Dario Leister
Thylakoids of land plants have a bipartite structure, consisting of cylindrical grana stacks, made of membranous discs piled one on top of the other, and stroma lamellae which are helically wound around the cylinders. Protein complexes predominantly located in the stroma lamellae and grana end membranes are either bulky [photosystem I (PSI) and the chloroplast ATP synthase (cpATPase)] or are involved in cyclic electron flow [the NAD(P)H dehydrogenase (NDH) and PGRL1-PGR5 heterodimers], whereas photosystem II (PSII) and its light-harvesting complex (LHCII) are found in the appressed membranes of the granum...
May 2014: Journal of Experimental Botany
https://www.readbyqxmd.com/read/22606172/2-11-dibromo-5-8-dibut-yl-4-helicene
#9
Hiroyuki Isobe, Taisuke Matsuno, Shunpei Hitosugi, Waka Nakanishi
A racemic mixture of the title compound, C(26)H(26)Br(2), a brominated [4]helicene, crystallizes, forming columns of stacked mol-ecules. There are two crystallographically unique mol-ecules in the asymmetric unit, both with the same helical handedness. As is typical with helicene congeners, the unique mol-ecules show short inter-atomic contacts between H atoms at the fjord region, with H⋯H distances of 1.87 and 1.94 Å. Mol-ecules with the same helical handedness segregate in the crystal packing, forming homochiral columns...
April 1, 2012: Acta Crystallographica. Section E, Structure Reports Online
https://www.readbyqxmd.com/read/22317218/mapping-of-noise-impact-provoked-by-the-execution-of-foundation-piles-at-high-rise-building-sites
#10
Adolpho Guido de Araújo, Alexandre Duarte Gusmão, Emilia Rahnemay Kohman Rabbani, Stela Paulino Fucale
The objective of this work is to map, in a limited area inside and outside of the worksite, the environmental impact generated by sound pollution coming from the driving of foundation piles for high rise buildings, as well as to observe and check if the noise levels produced by the emitting source are tolerable in the urban environment. The methodology of the work includes a survey of technical references about the subject; measurement of noises surrounding the worksite during the foundation phase for four distinct buildings, with different types of piles: prefabricated piles, continuous helical displacement piles , traditional compaction piles and Terra Probe compaction piles...
2012: Work: a Journal of Prevention, Assessment, and Rehabilitation
https://www.readbyqxmd.com/read/17140412/substitutions-in-the-n-terminal-alpha-helical-spine-of-neisseria-gonorrhoeae-pilin-affect-type-iv-pilus-assembly-dynamics-and-associated-functions
#11
Finn Erik Aas, Hanne C Winther-Larsen, Matthew Wolfgang, Stephan Frye, Cecilia Løvold, Norbert Roos, Jos P M van Putten, Michael Koomey
Type IV pili (Tfp) are multifunctional surface appendages expressed by many Gram negative species of medical, environmental and industrial importance. The N-terminally localized, so called alpha-helical spine is the most conserved structural feature of pilin subunits in these organelles. Prevailing models of pilus assembly and structure invariably implicate its importance to membrane trafficking, organelle structure and related functions. Nonetheless, relatively few studies have examined the effects of missense substitutions within this domain...
January 2007: Molecular Microbiology
https://www.readbyqxmd.com/read/16903146/amyloid-plaques-in-transmissible-spongiform-encephalopathies-prion-diseases
#12
REVIEW
Paweł P Liberski
Amyloid plaques are encountered in all cases of kuru and Gerstmann-Straussler-Scheinker disease (GSS) and in some 10-15% of sporadic Creutzfeldt-Jakob disease (sCJD) cases. In variant Creutzfeldt-Jakob (vCJD) the particular type of plaque known as "florid" or "daisy" plaque exists in 100% of cases. By electron microscopy several types of amyloid plaque were delineated, corresponding to those seen by PrP immunohistochemistry. Unicentric "kuru" plaques consisted of stellate arrangements (stars or cores) of amyloid bundles emanating from a dense interwoven centre...
2004: Folia Neuropathologica
https://www.readbyqxmd.com/read/16785325/structural-basis-for-tetraspanin-functions-as-revealed-by-the-cryo-em-structure-of-uroplakin-complexes-at-6-a-resolution
#13
Guangwei Min, Huaibin Wang, Tung-Tien Sun, Xiang-Peng Kong
Tetraspanin uroplakins (UPs) Ia and Ib, together with their single-spanning transmembrane protein partners UP II and IIIa, form a unique crystalline 2D array of 16-nm particles covering almost the entire urothelial surface. A 6 A-resolution cryo-EM structure of the UP particle revealed that the UP tetraspanins have a rod-shaped structure consisting of four closely packed transmembrane helices that extend into the extracellular loops, capped by a disulfide-stabilized head domain. The UP tetraspanins form the primary complexes with their partners through tight interactions of the transmembrane domains as well as the extracellular domains, so that the head domains of their tall partners can bridge each other at the top of the heterotetramer...
June 19, 2006: Journal of Cell Biology
https://www.readbyqxmd.com/read/16121398/cooperative-effects-in-hydrogen-bonding-of-protein-secondary-structure-elements-a-systematic-analysis-of-crystal-data-using-secbase
#14
O Koch, M Bocola, G Klebe
A systematic analysis of the hydrogen-bonding geometry in helices and beta sheets has been performed. The distances and angles between the backbone carbonyl O and amide N atoms were correlated considering more than 1500 protein chains in crystal structures determined to a resolution better than 1.5 A. They reveal statistically significant trends in the H-bond geometry across the different secondary structural elements. The analysis has been performed using Secbase, a modular extension of Relibase (Receptor Ligand Database) which integrates information about secondary structural elements assigned to individual protein structures with the various search facilities implemented into Relibase...
November 1, 2005: Proteins
https://www.readbyqxmd.com/read/15355399/measurement-accuracy-of-reconstructed-2-d-images-obtained-by-multi-slice-helical-computed-tomography
#15
Munetaka Naitoh, Akitoshi Katsumata, Eiji Nohara, Chiaki Ohsaki, Eiichiro Ariji
The present dental reconstructed computed tomography (CT) images consist of continuously piled-up axial CT images that are perpendicular to the axial CT plane. In the mandibular posterior region, the angles of designed implants frequently differ from the angles perpendicular to the axial CT plane and the measurement of mandibular height is inaccurate. This study was performed to clarify the measurement accuracy of double-oblique reconstructed images in multi-slice helical CT, using dried mandibles. The mandibular height was measured from the alveolar crest immediately below the aluminum tube to the superior border of the mandibular canal using the double-oblique reconstructed images and the micro-CT average images of three semi-lateral dried mandibles...
October 2004: Clinical Oral Implants Research
https://www.readbyqxmd.com/read/11853432/novel-superstructure-of-nondiscoid-mesogens-uneven-parallel-association-of-half-disk-molecules-3-4-5-trialkoxybenzoic-anhydrides-to-a-columnar-structure-and-its-one-directionally-geared-interdigitation
#16
Keiki Kishikawa, Shigetaka Furusawa, Takahiro Yamaki, Shigeo Kohmoto, Makoto Yamamoto, Kentaro Yamaguchi
Compact and simple nondiscoid mesogens, trialkoxybenzoic anhydrides 2-11 ((RO)(3)C(6)H(2)-CO-O-CO-C(6)H(2)(OR)(3), R = C(2)H(5), n-C(3)H(7), n-C(4)H(9), n-C(6)H(13), n-C(8)H(17), n-C(10)H(21), n-C(12)H(25), n-C(14)H(29), n-C(16)H(33), and (S)- and (R)-3,7-dimethyloctyl) were designed and synthesized, and their superstructures were investigated by polarized light microscopy, differential scanning calorimetry, calculation (MM2 and AM1), circular dichroism spectroscopy, and X-ray diffraction. As the result, in the cases of 5-9 and 11, the half-disk molecules in the liquid crystal phases were self-assembled by the dipole-dipole interaction between their carbonyl groups to a column in which the molecules were piled up in an alternately antiparallel manner, and the columns were interdigitated each other...
February 27, 2002: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/7934834/a-novel-determinant-coma-essential-for-natural-transformation-competence-in-neisseria-gonorrhoeae-and-the-effect-of-a-coma-defect-on-pilin-variation
#17
D Facius, T F Meyer
A novel genetic determinant (comA) has been identified and found to be required for the transformation of piliated Neisseria gonorrhoeae. Mutants in comA of strain MS11 grow normally and are DNA-uptake proficient but blocked in the translocation of DNA into the cytoplasm. Here we show by site-specific mutagenesis and genetic complementation that only one of two open reading frames identified in comA is essential for competence: it encodes a protein (ComA) with a predicted size of 74 kDa. The comA gene maps upstream of the iga locus and is transcribed in the opposite orientation, probably under the control of a putative sigma 54-type promoter...
November 1993: Molecular Microbiology
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