Using a molecular additive to control chiral supramolecular assembly and the subsequent chirality transfer process.

Hierarchical assembly of chiral molecules is achieved through the introduction of molecular additives, which enables the chiral assembly of nanosheets into helical nanorods with inverted chirality. Moreover, the hierarchical assembly of chiral molecules in the presence of a molecular additive can lead to the subsequent chirality transfer from a molecular system to nanoparticle assemblies.

Small Molecules Mediated the Chirality Transfer in Self-Assembled Nanocomposites with Strong Circularly Polarized Luminescence.

Manipulation of the chirality at all scales has a cross-disciplinary importance and may address key challenges at the heart of physical sciences. One critical question in this field is how the chirality of one entity can be transferred to the asymmetry of another entity. Here, we find that small molecules play a crucial role in the chirality transfer from chiral organic molecules to CdSe/CdS nanorods, where the handedness of the nanorod assemblies either agrees or disagrees with that of the molecular assemblies, leading to the positive or inverse chirality transfer.

Controlled Hierarchical Self-Assembly of Nanoparticles and Chiral Molecules into Tubular Nanocomposites.

In this work, we show how the kinetics of molecular self-assembly can be coupled with the kinetics of the colloidal self-assembly of inorganic nanoparticles, which in turn drives the formation of several distinct hierarchically assembled tubular nanocomposites with lengths over tens of micrometers. These colloidal nanoparticles primarily serve as "artificial histones," around which the as-assembled supramolecular fibrils are wound into deeply kinetically trapped single-layered nanotubes, which leads to the formation of tubular nanocomposites that are resistant to supramolecular transformation thermally. Alternatively, when these nanoparticles are aggregated prior to the event of molecular self-assembly, these as-formed nanoparticle "oligomers" would be encapsulated into the thermodynamically favored double-layer supramolecular nanotubes, which enables the non-close-packing of nanoparticles inside the nanotubes and results in the nanoparticle superlattices with an open channel.

Large Optical Asymmetry in Silver Nanoparticle Assemblies Enabled by CH-π Interaction-Mediated Chirality Transfer.

Transfer of asymmetry from the molecular system to the other distinct system requires appropriate chemical interactions. Here, we show how the CH-π interaction, one of the weakest hydrogen bonds, can be applied to transfer the asymmetry from π-conjugated chiral molecules to the assemblies of plasmonic Ag nanoparticles, where the aliphatic chains of chiral molecules and the polystyrene chains grafted on Ag nanoparticles are served as the hydrogen donor and acceptor, respectively. The optical asymmetry -factor of the chiral assemblies of plasmonic nanoparticles is strongly dependent on the molecular weight of the polystyrene ligand, the core structure of the molecule, and the aliphatic chain length of the chiral molecule.

Functional Droplets Stabilized by Interfacially Self-Assembled Chiral Nanocomposites.

Here, we show that aqueous dispersions of inorganic nanoparticles bearing negative surface charges would trigger the chiral assembly of organic radical cations solubilized in organic solvent at the liquid-liquid interface, which consequently produces stable droplets covered by a layer of inorganic/organic chiral nanocomposites. We demonstrate that chirality transfer across the liquid-liquid interface from the chiral organic monomers to the nanoparticle assemblies is realized. Surprisingly, opposite handedness between molecular assemblies and nanoparticle assemblies is determined from both CD and CPL measurements.

Folding of two-dimensional nanoparticle superlattices enabled by emulsion-confined supramolecular co-assembly.

Folding of two-dimensional nanoparticle superlattices is achieved through templated assembly on as-formed supramolecular nanosheets, which undergo a folding process within the emulsion droplets during the evaporation of the inner phase liquid. Building the folded nanoparticle superlattices opens a new gateway to reshape the properties of inorganic solids.

Diversifying Nanoparticle Superstructures and Functions Enabled by Translative Templating from Supramolecular Polymerization.

Biology exploits a transcription-translation approach to deliver structural information from DNA to the protein-building machines with high precision. Here, we show how the structural information of small synthetic molecules could be used to guide the assembly of inorganic nanoparticles into diversified yet long-range ordered superstructures, enabling the information transfer across four or five orders of magnitude in length scale. We designed three perylene diimide (PDI) based isomers differing by their site-specific substitutions of the methyl group, which were able to supramolecularly polymerize into diverse structures.

Active Regulation of Supramolecular Chirality through Integration of CdSe/CdS Nanorods for Strong and Tunable Circular Polarized Luminescence.

Building the cooperativity in artificial self-assembling systems will synergistically reshape their properties and expand their application spectrum. Here, we show how the cooperativity between achiral CdSe/CdS nanorods (NRs) and chiral perylene diimide (PDI)-based molecules is built upon their coassembly. We demonstrate that chirality transfer from chiral molecular assemblies to CdSe/CdS NRs is enabled by the encapsulation of NRs into PDI suprascrolls through chain-chain van der Waals interactions, which in turn gives rise to markedly enhanced circularly polarized luminescence of the nanocomposites.

Chirality Inversion in Self-Assembled Nanocomposites Directed by Curvature-Mediated Interactions.

Nanoscale curvature-dependent interactions are of paramount importance in biological systems. Here, we report that nanoscale curvature plays an important role in regulating the chirality of self-assembled nanocomposites from chiral organic molecules and achiral nanoparticles. Specifically, we show that the supramolecular chirality of the nanocomposites markedly depends on the nanoparticle curvature, where small-sized nanoparticles of high curvature and large-sized nanoparticles of low curvature lead to nanocomposites with opposite chirality.

Self-Assembled Open Porous Nanoparticle Superstructures.

Imparting porosity to inorganic nanoparticle assemblies to build up self-assembled open porous nanoparticle superstructures represents one of the most challenging issues and will reshape the property and application scope of traditional inorganic nanoparticle solids. Herein, we discovered how to engineer open pores into diverse ordered nanoparticle superstructures via their inclusion-induced assembly within 1D nanotubes, akin to the molecular host-guest complexation. The open porous structure of self-assembled composites is generated from nonclose-packing of nanoparticles in 1D confined space.

Discovering Topological Surface States of Dirac Points.

Dirac materials, unlike the Weyl materials, have not been found in experiments to support intrinsic topological surface states, as the surface arcs in existing systems are unstable against symmetry-preserving perturbations. Utilizing the proposed glide and time-reversal symmetries, we theoretically design and experimentally verify an acoustic crystal of two frequency-isolated three-dimensional Dirac points with Z_{2} monopole charges and four gapless helicoid surface states.

Monte Carlo simulations of stereocomplex formation in multiblock copolymers.

Currently, controlling the formation of stereocomplex crystallites (SCs) in enantiomeric PLA blends is a research hotspot. In the present work, we performed dynamic Monte Carlo simulations to study the formation mechanism of SCs in multiblock copolymers. The effects of block number and crystallization temperature on SC formation were revealed.

Stereocomplex formation in mixed polymers filled with two-dimensional nanofillers.

The presence of nanofillers, such as graphene, can effectively promote stereocomplex formation in poly(l-lactide)/poly(d-lactide) blends. However, the detailed microscopic mechanism of the improved formation of stereocomplex crystallites (SCs) in filled polylactides is still unclear. Therefore, we performed dynamic Monte Carlo simulations to reveal the underlying mechanism of the effect of two-dimensional nanofillers on the formation of SCs in polymer blends.

Ideal Weyl points and helicoid surface states in artificial photonic crystal structures.

Weyl points are the crossings of linearly dispersing energy bands of three-dimensional crystals, providing the opportunity to explore a variety of intriguing phenomena such as topologically protected surface states and chiral anomalies. However, the lack of an ideal Weyl system in which the Weyl points all exist at the same energy and are separated from any other bands poses a serious limitation to the further development of Weyl physics and potential applications. By experimentally characterizing a microwave photonic crystal of saddle-shaped metallic coils, we observed ideal Weyl points that are related to each other through symmetry operations.

Controllability of Polymer Crystal Orientation Using Heterogeneous Nucleation of Deformed Polymer Loops Grafted on Two-Dimensional Nanofiller.

Nowadays, it is a research hotspot to realize the controllability of polymer crystal structure in polymer nanocomposites. However, polymer crystals induced by two-dimensional filler always exhibit random orientation, which somewhat limit the improvement of physical properties of polymer materials. In the current paper, dynamic Monte Carlo simulations were performed to explore the methods preparing crystals with uniform orientation.

Surface plasmon resonance biosensor for sensitive detection of microRNA and cancer cell using multiple signal amplification strategy.

A sensitive and versatile surface plasmon resonance (SPR) biosensor was proposed for the detection of microRNA (miRNA) and cancer cell based on multiple signal amplification strategy. Thiol-modified hairpin probe, including a sequence complementary to the target miRNA, was first immobilized on the Au film. In the presence of target miRNA, the stem-loop structure of hairpin probe was unfolded, and then DNA-linked Au nanoparticles (AuNPs) were hybridized with the terminus of the unfolded hairpin probe.

High-Efficiency Broadband High-Harmonic Generation from a Single Quasi-Phase-Matching Nonlinear Crystal.

Nonlinear frequency conversion offers an effective way to expand the laser wavelength range based on birefringence phase matching (BPM) or quasi-phase-matching (QPM) techniques in nonlinear crystals. So far, efficient high-harmonic generation is enabled only via multiple cascaded crystals because of the extreme difficulty to simultaneously satisfy BPM or QPM for multiple nonlinear up-conversion processes within a single crystal. Here we report the design and fabrication of a chirped periodic poled lithium niobate (CPPLN) nonlinear crystal that offers controllable multiple QPM bands to support 2nd-8th harmonic generation (HG) simultaneously.

Observation of broadband unidirectional transmission by fusing the one-way edge states of gyromagnetic photonic crystals.

We experimentally demonstrate a broadband one-way transmission by merging the operating bands of two types of one-way edge modes that are associated with Bragg scattering and magnetic surface plasmon (MSP) resonance, respectively. By tuning the configuration of gyromagnetic photonic crystals and applied bias magnetic field, the fused bandwidth of unidirectional propagation is up to 2 GHz in microwave frequency range, much larger than either of the individual one-way bandwidth associated with Bragg scattering or MSP resonance. Our scheme for broadband one-way transmission paves the way for the practical applications of one-way transmission.

Isolated diastolic hypertension associated risk factors among Chinese in Anhui Province, China.

Objective: To explore potential risk factors of isolated diastolic hypertension (IDH) among young and middle-aged Chinese.

Methods: A community-based cross-sectional study was conducted among 338 subjects, aged 25 years and above, using random sampling technique. There were 68 cases of IDH, 46 cases of isolated systolic hypertension (ISH), 89 cases of systolic and diastolic hypertension (SDH), and 135 of subjects with normal blood pressure.

A sensitive one-step method for quantitative detection of α-amylase in serum and urine using a personal glucose meter.

Assays of α-amylase (AMS) activity in serum and urine constitute the important indicator for the diagnosis of acute pancreatitis, mumps, renal disease and abdominal disorders. Since these diseases confer a heavy financial burden on the health care system, AMS detection in point-of-care is fundamental. Here, a one-step assay for direct determination of the AMS activity was developed using a portable personal glucose meter (PGM).

Multiplex detection of nucleic acids using a low cost microfluidic chip and a personal glucose meter at the point-of-care.

A simple assay for multiplex DNA detection has been developed using a microfluidic chip and a personal glucose meter. By using this system, multiplex detection of three genotypes of hepatitis B virus DNA was possible with a detection limit of 10 pM. This point-of-care assay represented a versatile platform for sensitive multiplex target detection.

Reducing radiation losses of one-dimensional photonic-crystal reflectors on a silica waveguide.

Interferometric behaviours in radiation generation process of a one-dimensional photonic-crystal (PhC) reflector are investigated on a silica waveguide. An analytical model, which can calculate total radiation losses, is presented after analysing eigen-mode properties and radiation pattern characteristics. Our model takes into account the interference of component radiated waves generated at interfaces between different waveguide sections and is verified by comparing with numerical simulations of periodic and non-periodic one-dimensional PhC reflectors.

Gamma-Mu waveguides in two-dimensional triangular-lattice photonic crystal slabs.

We propose a line defect waveguide structure along the Gamma-Mu direction in two-dimensional triangular lattice silicon photonic crystal slabs. The modal dispersion relation and the transmission spectra of this waveguide are studied. The results show that by perturbing the width of the line defect and the diameter of the air holes adjacent to the waveguide core, one can control the width of the single mode transmission window and make it far broader than the original one.

Waveguide coupler in three-dimensional photonic crystal.

A waveguide coupler is designed and realized in a three-dimensional woodpile photonic crystal at microwave regime. This waveguide coupler shows good energy transfer property, which is confirmed through measurement of transmission spectrum, internal field distribution and surface field distribution using Agilent microwave network analyzer.

Near-field studies of microwave three-dimensional photonic crystals with waveguides.

By utilizing a vector network analyzer, the field distributions on the surface of a three-dimensional woodpile photonic crystal with a straight waveguide or a bend waveguide buried under the surface were measured in the microwave regime. The information of field profile and propagation characteristics of the guided modes can be successfully extracted from the surface near-field measurement. This work indicates that the near-field detection can become a promising means for experimental characterization of three-dimensional photonic crystal devices in supplement to the usual transmission spectrum measurement.