Construction Of Superstructures Research Articles

Programmable Metal/Semiconductor Nanostructures for mRNA-Modulated Molecular Delivery.

Cytotoxic chemotherapeutics are important tools for the clinical treatment of a variety of solid tumors. However, their use is often complicated by multidrug resistance that can develop in patients, limiting the potencies of these agents. New strategies are needed to provide versatile systems that can respond to and disable resistance mechanisms. We demonstrate the use of a new family of materials, programmable metal/semiconductor nanostructures, for drug delivery and mRNA sensing in drug-resistant cells. These materials are composed of a central core gold nanoparticle surrounded by a layer of DNA-capped quantum dots. The modularity of these "core-satellite" assemblies allows for the construction of superstructures with controlled size and the incorporation of multiple functionalities for drug delivery. The DNA sequence within the nanoparticle specifically binds to an mRNA encoding an important drug resistance factor, MRP1, inside cancer cells, releasing a potent anticancer drug doxorubicin. This event triggers a turn-on fluorescence emission along with a downregulation of the MRP1 drug efflux pump, a main resistance factor for doxorubicin, yielding a remarkable improvement in therapeutic efficacy against drug-resistant cancer cells. This work paves the way for the development of programmable materials with multiple synergistic functionalities for biomedical applications.

Opto-Thermophoretic Manipulation and Construction of Colloidal Superstructures in Photocurable Hydrogels

Light-based manipulation of colloidal particles holds great promise in fabrication of functional devices. Construction of complex colloidal superstructures using traditional optical tweezers is limited by high operation power and strong heating effect. Herein, we demonstrate low-power opto-thermophoretic manipulation and construction of colloidal superstructures in photocurable hydrogels. By introducing cationic surfactants into a hydrogel solution under a light-directed temperature field, we create both thermoelectric fields and depletion attraction forces to control the suspended colloidal particles. The particles of various sizes and compositions are thus trapped and organized into various superstructures. Furthermore, the colloidal superstructures are immobilized and patterned onto solid-state substrates through UV-induced photopolymerization of the hydrogel. Our opto-thermophoretic technique will open up avenues for bottom-up assembly of colloidal materials and devices.

Conditions of the transformation of the landscape of the residential quarter developed in the 1950s-1960s in the mass renovation

The relevance of the problem under investigation is due to the mass renovation of the existing landscape of residential quarters in Moscow. The purpose of the article is to disclose the influence of the urban-planning and investment potential on the development of pre-project proposals corresponding to the conditions for the renovation of the quarter without demolition and resettlement of residents, without demolition with resettlement of residents, with the full demolition and resettlement of residents with an assessment of the spatial properties of the newly formed landscape of the residential quarter. To solve this problem, a multivariate analysis of the results of design solutions for the renovation of existing buildings of quarters was made. It allowed to disclose the characteristic features of the transformation of landscape components caused by major repair, the installation of lift shafts, the construction of superstructures, attics, extensions and insertions, the reconstruction of existing and construction of new facilities of the pre-school and general education institution, an updated system of landscaping and greenery system, a street-road network and parking garages. The main results of the article show that the implementation of a multivariate analysis of pre-project solutions for renovation of the existing residential five-storey buildings of quarters having their own specifics and peculiarities will allow to obtain results that meet the interests of the administration, residents and investors, and also differentially approach to the accounting of social, financial, legal and other aspects of urban planning. The materials of the article can be useful for, urban planners, architects, builders, investors and administrative organs.

Cyclic Lateral Performance Evaluation of Precast Double-Skinned Composite Tubular Columns

Recently, bridge construction technology has experienced great progress with the development of high-performance materials and new structural types. On the contrary, most attention has been primarily paid to cast-in-place technologies and material cost savings. Even so, cast-in-place methods may present environmental issues at the construction sites, which frequently cause conflicts with residents. Thus, to overcome such disadvantages, precast methods have been strongly developed and especially applied in the construction of bridge superstructures. However, this has not been the case for substructures. Still, previous works on the development of precast solutions for such type of structures have been devoted to the design of double-skinned composite tubular (DSCT) columns. These studies included the design and construction methodology of precast segmental bent caps, column-bent cap, column-segment, and column-foundation joints. In this paper, the cyclic performance of precast DSCT columns was extensively analyzed experimentally. For this purpose, two test specimens were prepared, depending on the type of the segments connection, namely a splice plate and a mortar-grouting joint.

Molecular Engineering of Platinum(II) Terpyridine Complexes with Tetraphenylethylene-Modified Alkynyl Ligands: Supramolecular Assembly via Pt···Pt and/or π-π Stacking Interactions and the Formation of Various Superstructures.

A series of platinum(II) terpyridine complexes with tetraphenylethylene-modified alkynyl ligands has been designed and synthesized. The introduction of the tetraphenylethylene motif has led to aggregation-induced emission (AIE) properties, which upon self-assembly led to the formation of metal-metal-to-ligand charge transfer (MMLCT) behavior stabilized by Pt···Pt and/or π-π interactions. Tuning the steric bulk or hydrophilicity through molecular engineering of the platinum(II) complexes has been found to alter their spectroscopic properties and result in interesting superstructures (including nanorods, nanospheres, nanowires, and nanoleaves) in the self-assembly process. The eye-catching color and emission changes upon varying the solvent compositions may have potential applications in chemosensing materials for the detection of microenvironment changes. Furthermore, the importance of the directional Pt···Pt and/or π-π interactions on the construction of distinctive superstructures has also been examined by UV-vis absorption and emission spectroscopy and transmission electron microscopy. This work represents the interplay of both inter- and intramolecular interactions as well as the energies of the two different chromophoric/luminophoric systems that may open up a new route for the development of platinum(II)-AIE hybrids as functional materials.

Precisely Tailored DNA Nanostructures and their Theranostic Applications.

A critical challenge in nanotechnology is the limited precision and controllability of the structural parameters, which brings about concerns in uniformity, reproducibility and performance. Self-assembled DNA nanostructures, as a newly emerged type of nano-biomaterials, possess low-nanometer precision, excellent programmability and addressability. They can precisely arrange various molecules and materials to formspatially ordered complex, resulting in unambiguous physical or chemical properties.Because of these, DNA nanostructures have shown great promise in numerous biomedical theranostic applications. In this account, we briefly review the history and advances on construction of DNA nanoarchitectures and superstructures with accurate structural parameters. We focus on recent progress in exploiting these DNA nanostructures as platforms for quantitative biosensing, intracellular diagnosis, imaging, and smart drug delivery. We also discuss key challenges in practical applications.

Superstructures with diverse morphologies and highly ordered fullerene C60 arrays from 1 : 1 and 2 : 1 adamantane-C60 hybrid molecules.

Superstructures from fullerene C60-containing compounds, especially those tethered to rigid functional groups with defined shapes, remain largely unexplored. Being the smallest diamondoid, adamantane (Ad) can be viewed as a promising building block for the construction of well-defined superstructures. Here, we report the syntheses of 1 : 1 (4a) and 2 : 1 (4b) Ad-C60 hybrid molecules, which were then used to construct superstructures in binary solvent mixtures via a modified liquid/liquid interfacial precipitation (LLIP) method using CHCl3 as a good solvent. Typically in the combination of DMSO/CHCl3 with a final concentration (cf) of 1.0 mmol L-1, 4a successively forms spheres, plates, nanoflowers and plicated particles with increasing content of DMSO while 4b forms cuboid blocks and microparticles with hierarchically organized surfaces. Changing from DMSO to other poor solvents including acetone, MeOH and EtOAc leads to variations of the morphology of the superstructures for both 4a and 4b. At the nanometer length scale, 4a and 4b adopt different organizations within the superstructures. While 4a tends to self-organize into lamellae with highly ordered C60 layers, the hexagonal phase is dominant in the superstructures formed by 4b. Wettability tests indicate that films formed by the superstructures of 4a and 4b show anti-wetting properties. Besides the solvent effect, the morphology of the superstructures can be also tuned by concentration. For example, when cf is lowered to 0.5 mmol L-1, a new form of superstructure, i.e., fibers, was detected for 4a. Our results also indicate that besides the solvent-induced aggregate transition, gravity-induced sedimentation and subsequent structure ripening can have a significant influence on the final morphology of the superstructures and the aggregate transition pathways.

Two-Dimensional Mesoscale-Ordered Conducting Polymers.

Despite the availability of numerous two-dimensional (2D) materials with structural ordering at the atomic or molecular level, direct construction of mesoscale-ordered superstructures within a 2D monolayer remains an enormous challenge. Here, we report the synergic manipulation of two types of assemblies in different dimensions to achieve 2D conducting polymer nanosheets with structural ordering at the mesoscale. The supramolecular assemblies of amphipathic perfluorinated carboxylic acids and block co-polymers serve as 2D interfaces and meso-inducing moieties, respectively, which guide the polymerization of aniline into 2D, free-standing mesoporous conducting polymer nanosheets. Grazing-incidence small-angle X-ray scattering combined with various microscopy demonstrates that the resulting mesoscale-ordered nanosheets have hexagonal lattice with d-spacing of about 30 nm, customizable pore sizes of 7-18 nm and thicknesses of 13-45 nm, and high surface area. Such template-directed assembly produces polyaniline nanosheets with enhanced π-π stacking interactions, thereby resulting in anisotropic and record-high electrical conductivity of approximately 41 S cm(-1) for the pristine polyaniline nanosheet based film and approximately 188 S cm(-1) for the hydrochloric acid-doped counterpart. Our moldable approach creates a new family of mesoscale-ordered structures as well as opens avenues to the programmed assembly of multifunctional materials.

Experimental and numerical evaluation of a folded plate girder system for short-span bridges – A case study

Bridge owners and engineers focusing on bridge design, management and maintenance continue to search for more efficient ways to design, construct, and maintain their bridge inventory. Recently, a folded plate girder system has been promoted as a cost-effective alternative for the design and construction of bridge superstructures due to merits such as low cost and facilitation of accelerated bridge construction. The folded plate girder system has a structural shape strategically press-brake formed from a single sheet of plate steel and achieves composite action with a concrete deck utilizing shear studs in between. To further facilitate the development and adaptation of the system for bridge application, this paper presents a systematic performance evaluation of the folded plate girder system through experimental and numerical programs. To this end, a folded plated girder specimen was designed, fabricated, and tested to evaluate the constructability and capacity of the girder specimen. Finite Element (FE) Analysis was performed to understand the behavior of the girder specimen under different loading conditions. The predictions using traditional design calculations and FE analysis were compared with the test results. After the FE models were validated against the test data, a full bridge model was established to further investigate the behavior of the bridge under loading condition up to the ultimate load. It was found that the ultimate capacity of the bridge girders were much higher than the bridge demand and the bridge had good ductility until failure. The predictions using the design calculations based on the AASHTO LRFD Bridge Design Specifications were in reasonable agreement with the test results. The FE models showed better predictions since more sophisticated modeling techniques and material constitutive models were used. Results obtained from the sophisticated non-linear bridge model indicated that the girder distribution factors varied along with an increase of the truck loading and especially their change trend was gradually reversed after the yield of the girder steel. And according to the FE results, the distribution factor based on the AASHTO LRFD Bridge Design Specifications was sufficient for the design of the folded plate girder bridge investigated in this study.

Innovative Technology Research on the Construction of Super Large Cable Net Structures - Application of the FAST Project of the National Astronomical Observatory

Innovative Technology Research on the Construction of Super Large Cable Net Structures - Application of the FAST Project of the National Astronomical Observatory

PH-Sensitive polymer assisted self-aggregation of bis(pyrene) in living cells in situ with turn-on fluorescence

Supramolecular self-assemblies with various nanostructures in organic and aqueous solutions have been prepared with desired functions. However, in situ construction of self-assembled superstructures in physiological conditions to achieve expected biological functions remains a challenge. Here, we report a supramolecular system to realize the in situ formation of nanoaggregates in living cells. The bis(pyrene) monomers were dispersed inside of hydrophobic domains of pH-sensitive polymeric micelles and delivered to the lysosomes of cells. In the acidic lysosomes, the bis(pyrene) monomers were released and self-aggregated with turn-on fluorescence. We envision this strategy for in situ construction of supramolecular nanostructures in living cells will pave the way for molecular diagnostics in the future.

Simultaneous synthesis and assembly of silver nanoparticles to three-demensional superstructures for sensitive surface-enhanced Raman spectroscopy detection.

Construction of superstructures with controllable morphologies from NPs is of great scientific and technological importance. A one-step method for simultaneous synthesis and assembly of Ag NPs to three-dimensional (3D) nanoporous superstructures is demonstrated. By varying the adsorption time of Ag precursors, an array of well-defined Ag superstructures with different morphologies are harvested. A "hot spot"-rich substrate for surface-enhanced Raman spectroscopy is established, which exhibits high sensitivity in trace detection of molecules. It is believed that the presented 3D nanoporous Ag superstructures hold great potential for various uses, such as novel multifunctional sensing and monitoring chips or devices.

ANP Model for Evaluation of False-work Systems for Cast-in-place Cantilever Bridges

The terrain of Taiwan is characterized by large areas of mountains, while lands in urban areas have become increasingly difficult to acquire for developing infrastructures. To reduce environmental impacts and to improve traffic conditions, highway projects have adopted more and more bridges over the years and many advanced bridge construction methods have been introduced. In terms of construction of bridge superstructures, the cast-in-place cantilever method has seen wider use with many successful examples. This study investigated the false-work systems that may be selected for use in implementing the cast-in-place cantilever method in Taiwan, with the objective of developing a model for evaluating possible options. Based on a review of related researches, an evaluation framework for the false-work systems has been proposed first, which consists of six factors: system controllability, structural stability, initial cost, operating cost, segment cycle time, and closing segment construction time that are categorized into three aspects: reliability, cost, and speed. Because of the interdependencies among the factors, the model uses the analytic network process (ANP) to produce the weights of the factors and the ratings of the options in given project conditions. An illustrative example is provided, in which three false-work systems considered for a hypothetical box-girder bridge project are evaluated. The rankings of the options obtained for the example from best to worst were triangular truss, diamond truss, and suspension truss. Practitioners may use the model as a decision aid in evaluating and selecting false-work systems for the cast-in-place cantilever method for construction of bridge superstructures.

Antisolvent Crystallization Approach to Construction of CuI Superstructures with Defined Geometries

A facile high-yield production of cuprous iodide (CuI) superstructures is reported by antisolvent crystallization using acetonitrile/water as a solvent/antisolvent couple under ambient conditions. In the presence of trace water, the metastable water droplets act as templates to induce the precipitation of hollow spherical CuI superstructures consisting of orderly aligned building blocks after drop coating. With water in excess in the mixed solution, an instant precipitation of CuI random aggregates takes place due to rapid crystal growth via ion-by-ion attachment induced by a strong antisolvent effect. However, this uncontrolled process can be modified by adding polymer polyvinyl pyrrolidone (PVP) in water to restrict the size of initially formed CuI crystal nuclei through the effective coordination effect of PVP. As a result, CuI superstructures with a cuboid geometry are constructed by gradual self-assembly of the small CuI crystals via oriented attachment. The precipitated CuI superstructures have been used as competent adsorbents to remove organic dyes from the water due to their mesocrystal feature. Besides, the CuI superstructures have been applied either as a self-sacrificial template or only as a structuring template for the flexible design of other porous materials such as CuO and TiO2. This system provides an ideal platform to simultaneously investigate the superstructure formation enforced by antisolvent crystallization with and without organic additives.

BP-PSO-based intelligent case retrieval method for high-rise structural form selection

Modern architectures are developing in the direction of tall buildings and complex structures, and the theoretical analysis and the design experience have seriously lagged behind the construction of super high-rise structures. Structural form selection, especially the case based reasoning (CBR) based structural form selection, is a promising tool for the construction of high-rise structures. In view of the limit of cognitive ability of domain experts, a BP (back propagation)-PSO (particle swarm optimization)-based intelligence case retrieval method for high-rise structural form selection is proposed. The CBR-based case retrieval method and the construction of the BP-PSO neutral network are introduced. And then the BP-PSO-based case retrieval method is validated by some engineering cases. The results of training and prediction indicate that the proposed method has good ability to retrieve the cases of high-rise structures.

Hierarchical Assembly of Complex Block Copolymer Nanoparticles into Multicompartment Superstructures through Tunable Interparticle Associations

AbstractA challenging aim in both materials physics and chemistry is the construction of complex and functional superstructures from designed nanoscale building units. Block copolymer nanoparticles with morphological variety and compositional complexity have been made with solution‐based assembly. However, routine ability to build hierarchical superstructures by inter‐nanoparticle association is not yet possible. A hierarchical assembly strategy of organizing pre‐formed spherical block copolymer nanoparticles into superstructures, including linear, circular, and close‐packed arrays, via tunable interparticle interactions is presented. Solution‐state mixtures are made of two amphiphilic diblock copolymers, poly(acrylic acid)‐block‐poly(methyl methacrylate) (PAA‐b‐PMMA) and poly(acrylic acid)‐block‐polybutadiene (PAA‐b‐PB) with additional crown ether functionalities grafted onto 40 mol% of the AA repeat units on the PAA‐b‐PMMA diblock copolymer. Through kinetic control of the solution assembly process in aqueous/N,N‐dimethylformamide (DMF) mixtures (4:1 water:DMF), spherical nanoparticles with compositional complexity confined in both the core and shell are obtained. Benefiting from host‐guest chemistry, interparticle association is triggered and tuned by the addition of di‐functional organoamines due to amine‐crown ether complexation. The resultant multiparticle superstructures contain well‐defined multicompartments within individual, constituent nanoparticles due to the local separation of unlike PB and PMMA hydrophobic blocks within the cores of the individual particles. Through competitive complexation with potassium ions, the superstructures are disassembled into individual multicomparment nanoparticles.

デヒドロベンゾ[12]アヌレン誘導体による一次元包接空間を有する超構造の構築

デヒドロベンゾ[12]アヌレン誘導体による一次元包接空間を有する超構造の構築

Construction of nanoparticle superstructures on the basis of host–guest interaction to achieve performance integration and modulation

Creation of nanoparticle (NP) architectures via a self-assembly strategy is the current means to integrate and/or modulate the functionalities of NPs. In this paper, we demonstrate the capability for constructing NP spherical superstructures through the specific interaction between host and guest molecules, for instance the model system of α-cyclodextrin (α-CD) and oleic acid (OA), which are decorated on two different NPs beforehand. Subsequently, the OA-decorated hydrophobic NPs are dispersed in hexane, whereas the α-CD-decorated NPs are dispersed in water. The blending of these two immiscible solutions produces NP binary superstructures because of the multiple linkages between the α-CD- and OA-decorated NPs. Control experiments indicate that the self-assembly of NPs occurs either at the hexane/water interface to form hybrid films or in the aqueous phase to generate spherical architectures, which strongly depends on the amount and the size of α-CD-decorated NPs. The high ratio and small size of the α-CD-decorated NPs facilitate the formation of spherical architectures. Competitive experiments with the addition of host α-CD and guest sodium oleate clearly confirm that the main driving force for the NP co-assembly is the specific interaction between α-CD and OA. In addition, the flexible decoration of α-CD and OA on the NPs makes the current strategy generally applicable for a variety of NPs, such as the superstructures of Au/Fe(3)O(4), Pt/Fe(3)O(4), and Au/NaYF(4):Yb,Tm, which is expected to promote the further application of NPs in environmental and biological sciences.

Synthesis of dissymmetrical nanoparticles with a new hybrid silica template

An easy, novel route to prepare Janus nanoparticles and nano-bowls with tunable shapes has been developed. This approach uses a new kind of monodisperse vinyl-silica nanoparticles as templates to obtain large amounts of uniform Janus particles and nano-bowls (several grams). The efficient method adopts water-based hydrolysis-condensation and seed-emulsion polymerization. The uniform Janus nanoparticles and nano-bowls will display wide potential applications in many fields, such as: chemical sensors, construction of complex superstructures and nano-bioreactors.

Stepwise Self-Assembly of DNA Tile Lattices Using dsDNA Bridges

The simple helical motif of double-strand DNA (dsDNA) has typically been judged to be uninteresting for assembly in DNA-based nanotechnology applications. In this letter, we demonstrate construction of superstructures consisting of heterogeneous DNA motifs using dsDNA in conjunction with more complex, cross-tile building blocks. Incorporation of dsDNA bridges in stepwise assembly processes can be used for controlling length and directionality of superstructures and is analogous to the "reprogramming" of sticky-ends displayed on the DNA tiles. Two distinct self-assembled DNA lattices, fixed-size nanoarrays, and extended 2D crystals of nanotracks with nanobridges, are constructed and visualized by high-resolution, liquid-phase atomic force microscopy.