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Three-dimensional Architecture (three-dimensional + architecture)
Selected AbstractsOne Novel Vanadium-Phosphate Cluster [PV2.5O8.5]×3.83{H2O} with Three-Dimensional Architecture.CHEMINFORM, Issue 1 2007Ying Liu Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Fabrication of Graphene,Polymer Nanocomposites With Higher-Order Three-Dimensional ArchitecturesADVANCED MATERIALS, Issue 21 2009Jemma L. Vickery The use of aqueous dispersions of polystyrene sulfonate-stabilized graphene sheets for the fabrication of nanocomposites with higher-order 3D architectures is demonstrated using two examples of template-directed assembly. Macroscopic sponge-like polymer,graphene scaffolds are readily produced by directional freeze casting, while hollow graphene microspheres are prepared by electrostatically induced assembly on positively charged polymer beads. [source] Development of three-dimensional architecture of the neuroepithelium: Role of pseudostratification and cellular ,community'DEVELOPMENT GROWTH & DIFFERENTIATION, Issue 2008Takaki Miyata This review discusses the development of the neuroepithelium (NE) and its derivative ventricular zone (VZ), from which the central nervous system (CNS) is formed. First, the histological features of the NE and VZ are summarized, highlighting the phenomenon of pseudostratification, which is achieved by polarization and interkinetic nuclear migration (INM) of neural progenitor cells. Next, our current understanding of the cellular and molecular mechanisms and biological significance of INM and pseudostratification are outlined. The recent three-dimensional time-lapse observations revealing heterogeneity in cell lineages within the NE and VZ are also described, focusing on the neuronal lineage. Finally, the necessity of comprehensive studies on cell-cell interactions in the NE/VZ is discussed, as well as the importance of electrophysiological and biomechanical approaches. In particular, we suggest that a systems biology approach to the NE/VZ as a cellular ,community' may be fruitful. [source] Biodegradable comb polyesters containing polyelectrolyte backbones facilitate the preparation of nanoparticles with defined surface structure and bioadhesive properties,POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 10-12 2002A. Breitenbach Abstract A major challenge in oral peptide and protein delivery remains the search for suitable carrier systems. Therefore, a new concept was investigated combining a modified three-dimensional architecture, increased hydrophilicity of poly(lactic- co -glycolic acid) (PLGA) and charged groups in a single polymer. Biodegradable comb PLGA were synthesized by grafting short PLGA chains onto different poly(vinyl alcohol) (PVA) based backbone polyols, poly(2-sulfobutyl-vinyl alcohol) and poly(diethylaminoethyl-vinyl alcohol). The polyelectrolyte backbones were obtained by etherification of PVA with charge-containing pendent groups. The comb polymer structure could be confirmed by nuclear magnetic resonance, infrared spectroscopy, differential scanning calorimetry, elemental analysis and measurement of intrinsic viscosity. Nanoparticles (NP), as potential mucosal carriers systems, were prepared by controlled precipitation and investigated as a function of polymer composition. The amphiphilic character and the three-dimensional architecture of the novel polyesters allowed the preparation of small nanoparticles even without the use of surfactants. Surface NMR, surface charge and hydrophobicity determination indicate a core,corona-like NP structure, especially in the case of negatively charged polyesters. A structural model is proposed for the NP with an inner polyester core and an outer charged-groups-containing surface, depending on polymer composition and backbone charge density. The higher the polymer backbone charge density, the more pronounced its influence on the nanoparticle surface properties. The possibility of preparing NP without the use of a surfactant, as well as of designing the NP surface characteristics by polymer backbone charge density and polymer hydrophilic,hydrophobic balance, will be a major advantage in protein adsorption, bioadhesion and organ distribution. This makes these biodegradable polymers promising candidates for colloidal protein and peptide delivery. Copyright © 2003 John Wiley & Sons, Ltd. [source] 7-Methoxy-2,3-dioxo-1,4-dihydroquinoxalin-6-aminium chloride monohydrateACTA CRYSTALLOGRAPHICA SECTION C, Issue 1 2010Jürgen Brüning Single crystals of the title compound, C9H10N3O3+·Cl,·H2O, were obtained by recrystallization from hydrochloric acid. The cations stack along the crystallographic a direction. The 2,3-dioxo-1,4-dihydroquinoxaline group shows a significant deviation from planarity [r.m.s. deviation from the best plane = 0.063,(2),Å]. Hydrogen bonding links the cations, chloride anions and water molecules to form an extended three-dimensional architecture. [source] Hydrogen-bonded three-dimensional network of a lanthanum(III) exocyclic complex with 5,10,15,20-tetra-4-pyridylporphyrinACTA CRYSTALLOGRAPHICA SECTION C, Issue 10 2009Sophia Lipstman In the complex diaquatetranitrato[5-(pyridinium-4-yl)-10,15,20-tri-4-pyridylporphyrin]lanthanum(III) 1,2-dichlorobenzene trisolvate, [La(NO3)4(C40H27N8)(H2O)2]·3C6H4Cl2, the lanthanum ion is coordinated to one of the peripheral pyridyl substituents of the porphyrin entity. Units of the complex are interlinked to one another in three dimensions by a network of O,H...N, O,H...O and N,H...O hydrogen bonds between the water ligands, nitrate ions, and pyridyl and pyridinium groups of adjacent species. This is the first structural report of an exocyclic complex of the tetrapyridylporphyrin ligand with any lanthanide ion and its self-assembly into a three-dimensional architecture sustained by hydrogen bonds. [source] Immunohistochemical and scanning electron microscopic comparison of the collagen network constructions between pig, goat and chicken liversANIMAL SCIENCE JOURNAL, Issue 4 2009Shotaro NISHIMURA ABSTRACT The distribution and three-dimensional architecture of collagen fibers were compared between pig, goat and chicken livers. Immunohistochemical staining revealed that collagen type I was identified in the interlobular connective tissue region and intralobular areas in pigs and goats. Type III collagen was also identified in the interlobular connective tissue region and intralobular sinusoidal walls. In the chicken liver, only the circumference region of the vessels was immunostained with collagen type I and III antibodies and the interlobular connective tissue wall could not be distinguished clearly. In the intralobular region, collagen type I antibody immunoreacted around the hepatic cells but collagen type III antibody immunoreacted weakly. In the NaOH macerated specimen, well-developed collagen bundles formed the prominent interlobular walls in pigs. In contrast, the wall in the goat liver comprised a thin layer of the bundles. In the chicken liver, there were no notable collagen septa between lobules. The intralobular collagen construction was quite different between the animals, indicating a fragile collagen fibril networks in pigs, a robust framework in goats and dense fabric-like septa in chickens. These results indicate that the distinct collagen frameworks may contribute to the histological strength of the livers in each of the animal species. [source] Hydrogen-bond-directed supramolecular arrays in 4,4,-bipyridinium tetrachloroterephthalate dihydrate and bis(1,10-phenanthrolinium) tetrachloroterephthalate tetrachloroterephthalic acid trihydrateACTA CRYSTALLOGRAPHICA SECTION C, Issue 10 2009Ming-Yang He The title compounds, C10H10N22+·C8Cl4O42,·2H2O, (I), and 2C12H9N2+·C8Cl4O42,·C8H2Cl4O4·3H2O, (II), both crystallize as charge-transfer organic salts with the dianionic or neutral acid components lying on inversion centres. The acid and base subunits in (I) arrange alternately to generate a linear tape motif via N,H...O hydrogen bonds; these tapes are further combined into a three-dimensional architecture through multiple O,H...O and C,H...O interactions involving solvent water molecules. In contrast, the neutral and anionic acid components in (II) are linked to form a zigzag chain by means of O,H...O hydrogen bonds between acid groups, with dangling 1,10-phenanthrolinium units connected to these chains by carboxylate,pyridinium interactions with R22(7) hydrogen-bond notation. Adjacent chains are further extended to result in a two-dimensional corrugated layer network via,,, interactions. Inter-ion Cl...O interactions are also found in both (I) and (II). [source] Three-dimensional framework structures: isomorphous bis(2,6-diamino-3,5-dibromopyridinium) tetrabromidometallate(II) salts with CdII and MnIIACTA CRYSTALLOGRAPHICA SECTION C, Issue 8 2009Rawhi H. Al-Far In the structural motifs of two isomorphous triclinic salts, (C5H6Br2N3)2[MBr4] (M = CdII and MnII), each [MBr4]2, anion interacts with eight surrounding 2,6-diamino-3,5-dibromopyridinium cations through intermolecular C/N,H...Br and Br...Br interactions, leading to a three-dimensional framework structure. The cations show a minor degree of ,,, stacking, adding extra stability to the three-dimensional architecture. [source] A cyano-bridged dinuclear 4f,3d arrayACTA CRYSTALLOGRAPHICA SECTION C, Issue 6 2002Hui-Zhong Kou A cyano-bridged bimetallic 4f,3d complex, triaqua-1,3O -,-cyano-1:2,2N:C -pentacyano-2,5C -tetrakis(2-pyrrolidone-1,O)chromium(III)dysprosium(III) dihydrate, [CrDy(C4H7NO)4(CN)6(H2O)3]·2H2O, has been prepared and characterized by X-ray crystallographic analysis. The structure consists of a neutral cyano-bridged Dy,Cr dimer. A hydrogen-bonded three-dimensional architecture is formed through N,H,O, O,H,N and O,H,O hydrogen bonds. [source] Three-dimensional study of the musculotendinous architecture of supraspinatus and its functional correlationsCLINICAL ANATOMY, Issue 6 2007Soo Y. Kim Abstract The supraspinatus is most frequently involved in shoulder pathology. However, the musculotendinous architecture of the supraspinatus has not been well documented. Therefore, the purpose of this study is to investigate the detailed three-dimensional architecture of the supraspinatus throughout its volume. Ten male formalin embalmed cadaveric specimens (mean age 61.9 ± 16 years) without any evidence of rotator cuff pathology were used. Three-dimensional coordinates (x, y, and z) of the tendon and muscle fiber bundles were collected in situ, using serial dissection and digitization. The data was reconstructed into a three-dimensional model using MayaÔ. Fiber bundle lengths, pennation angles (PA), muscle volumes, and tendon dimensions for each architecturally distinct area were computed and then analyzed using paired t -tests and ANOVA (P < 0.05). The supraspinatus was found to consist of anterior and posterior regions, which were each further subdivided into superficial, middle, and deep parts. Mean PA were found to be significantly different between the distinct parts of the anterior region of the muscle. Medial PA was also found be significantly different between the superficial and middle, and superficial and deep parts of the posterior region. These results provide insight into the normal function of the muscle and its possible contribution to the initiation and progression of supraspinatus tendon tears. Clin. Anat. 20:648,655, 2007. © 2007 Wiley-Liss, Inc. [source] High-Resolution Patterning of Hydrogels in Three Dimensions using Direct-Write Photofabrication for Cell GuidanceADVANCED FUNCTIONAL MATERIALS, Issue 22 2009Stephanie K. Seidlits Abstract The development of three-dimensional, spatially defined neuronal cultures that mimic chemical and physical attributes of native tissue is of considerable interest for various applications, including the development of tailored neuronal networks and clinical repair of damaged nerves. Here, the use of multiphoton excitation to photocrosslink protein microstructures within three-dimensional, optically transparent hydrogel materials, such as those based on hyaluronic acid, is reported. Multiphoton excitation confines photocrosslinking to a three-dimensional voxel with submicron spatial resolution, enabling fabrication of protein matrices with low- to sub-micrometer feature sizes by scanning the focus of a laser relative to the reagent solution. These methods can be used to create complex three-dimensional architectures that provide both chemical and topographical cues for cell culture and guidance, providing for the first time a means to direct cell adhesion and migration on size scales relevant to in vivo environments. Using this approach, guidance of both dorsal root ganglion cells (DRGs) and hippocampal neural progenitor cells (NPCs) along arbitrary, three-dimensional paths is demonstrated. [source] Hierarchical structures of dendritic polymersPOLYMER INTERNATIONAL, Issue 2 2010Masaki Ujihara Abstract Dendritic polymers' highly specific and three-dimensional architectures set them apart from linear and slightly branched polymers. Their unique properties also allow them to form hierarchical organizations, which can be classified as planar or non-planar. The preparation of a planar hierarchy consisting of dendritic polymers can be achieved by conventional techniques of adsorption or Langmuir monolayer and Langmuir,Blodgett accumulation, and the resultant hierarchy is well ordered. Non-planar hierarchies are built on non-planar scaffolds, for example by self-assembly. In this mini-review, the practical/potential applications of dendritic polymers such as for electrical or optical devices, sensing systems, or medical diagnosis are also reviewed in association with their structures. Copyright © 2009 Society of Chemical Industry [source] | ||||||||||||||||