The off‐stoichiometry effects and gram‐scale production of luminescent CuInS2‐based semiconductor nanocrystals, as well as their application in electroluminescence devices are reported. The crystal structures and optical properties of CuInS2 nanocrystals can be significantly influenced by controlling their [Cu]/[In] molar ratio. A simple model adapted from the bulk materials is proposed to explain their off‐stoichiometry effects. Highly emissive and color‐tunable CuInS2‐based NCs are prepared by a combination of [Cu]/[In] molar ratio optimization, ZnS shell coating, and CuInS2–ZnS alloying. The method is simple, hassle‐free, and easily scalable to fabricate tens of grams of nanocrystal powders with photoluminescence quantum yields up to around 65%. Furthermore, the performance of high‐quality CuInS2‐based NCs in electroluminescence devices is examined. These devices have lower turn‐on voltages of around 5 V, brighter luminance up to approximately 2100 cd m−2 and improved injection efficiency of around 0.3 lm W−1 (at 100 cd m−2) in comparison to recent reports.

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A novel giant surfactant possessing a well-defined hydrophilic head and a hydrophobic polymeric tail, polystyrene-(carboxylic acid-functionalized polyhedral oligomeric silsesquioxane) conjugate (PS-APOSS), has been designed and synthesized via living anionic polymerization, hydrosilylation, and thiol-ene "click" chemistry. PS-APOSS forms micelles in selective solvents, and the micellar morphology can be tuned from vesicles to wormlike cylinders and further to spheres by increasing the degree of ionization of the carboxylic acid. The effect of APOSS-APOSS interactions was proven to be essential in the morphological transformation of the micelles. The PS tails in these micellar cores were found to be highly stretched in comparison with those in traditional amphiphilic block copolymers, and this can be explained in terms of minimization of free energy. This novel class of giant surfactants expands the scope of macromolecular amphiphiles and provides a platform for the study of the basic physical principles of their self-assembly behavior.

Due to their wide tunable bandgaps, high absorption coefficients, easy solution processabilities, and high stabilities in air, lead sulfide (PbS) quantum dots (QDs) are increasingly regarded as promising material candidates for next-generation light, low-cost, and flexible photodetectors. Current single-layer PbS-QD photodetectors suffer from shortcomings of large dark currents, low on-off ratios, and slow light responses. Integration with metal nanoparticles, organics, and high-conducting graphene/nanotube to form hybrid PbS-QD devices are proved capable of enhancing photoresponsivity; but these approaches always bring in other problems that can severely hamper the improvement of the overall device performance. To overcome the hurdles current single-layer and hybrid PbS-QD photodetectors face, here a bilayer QD-only device is designed, which can be integrated on flexible polyimide substrate and significantly outperforms the conventional single-layer devices in response speed, detectivity, linear dynamic range, and signal-to-noise ratio, along with comparable responsivity. The results which are obtained here should be of great values in studying and designing advanced QD-based photodetectors for applications in future flexible optoelectronics.

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The mechanism of latent tuberculosis (TB) infection remains elusive. Several host factors that are involved in this complex process were previously identified. Micro RNAs (miRNAs) are endogenous ∼22 nt RNAs that play important regulatory roles in a wide range of biological processes. Several studies demonstrated the clinical usefulness of miRNAs as diagnostic or prognostic biomarkers in various malignancies and in a few nonmalignant diseases. To study the role of miRNAs in the transition from latent to active TB and to discover candidate biomarkers of this transition, we used human miRNA microarrays to probe the transcriptome of peripheral blood mononuclear cells (PBMCs) in patients with active TB, latent TB infection (LTBI), and healthy controls. Using the software package BRB Array Tools for data analyses, 17 miRNAs were differentially expressed between the three groups (P<0.01). Hierarchical clustering of the 17 miRNAs expression profiles showed that individuals with active TB clustered independently of individuals with LTBI or from healthy controls. Using the predicted target genes and previously published genome-wide transcriptional profiles, we constructed the regulatory networks of miRNAs that were differentially expressed between active TB and LTBI. The regulatory network revealed that several miRNAs, with previously established functions in hematopoietic cell differentiation and their target genes may be involved in the transition from latent to active TB. These results increase the understanding of the molecular basis of LTBI and confirm that some miRNAs may control gene expression of pathways that are important for the pathogenesis of this infectious disease.

The layer-by-layer (LbL) method has proved to be a simple but versatile technique for the construction of self-assembled films with controlled thickness and composition since it was first introduced by Decher et al. [1] Using this method, biopolymers, electroactive polymers, and photoactive polymers can be easily introduced into thin films. The resulting films can be bio-, electro-, or photoactive. [2] One advantage of the LbL method is that there is no restriction on the size and morphology of the substrate on which the film is constructed, which implies that the LbL method can be extended from twodimensional (2D) systems (i.e., planar substrates) to threedimensional (3D) systems (for example, spherical or other non-planar substrates). Consequently, a large variety of core± shell particles with finely tuned polymer layer thickness and compositions have been synthesized, [3] and a series of novel hollow microcapsules fabricated by subsequent removal of the sacrificial core of the resulting core±shell particles.[4] Since these supramolecular assemblies offer exciting prospects for the encapsulation of drugs, enzymes, proteins, and other active materials, they are attracting more and more attention.Up to now almost all papers in this area have employed the electrostatic self-assembly method, which is based on the sequential adsorption of oppositely charged polyelectrolytes, except for several cases with some minor modifications.[5] On the other hand, LbL strategies employing other driving forces, such as the hydrogen bond, have been developed.[6] Hydrogen-bonding self-assembly (HSA) was first introduced by Stockton and Rubner in 1997.[6a] Since then, several pairs of polymers have been successfully used in the self-assembly processes.[6b±f] However, no success has been reported in extending the HSA method from 2D to 3D systems and preparing hollow capsules by further removing the sacrificial core. One reason for the increased difficulty of this hydrogen-bonding process is the fact that hydrogen bonding is much weaker than the electrostatic interaction; consequently, rupture may occur when the sacrificial core is being removed. Since the formation and destruction of hydrogen bonds can be controlled easily by external stimuli, such as pH, [6d±f] capsules based on hydrogen bonding may have great merit when being used in controlled drug-release systems. In this report, we demonstrate that it is possible to extend the HSA method from 2D to 3D systems and further to prepare hollow capsules with successful procedures in removing the sacrificial core without rupturing the multilayer shell. Poly(vinylpyrrolidone), PVP, and m-methylphenol-formaldehyde resin (MPR) are employed as hydrogen acceptor and donor, respectively, in this method. Self-assembled films were first fabricated on planar substrates, i.e., quartz and silica slides, to examine the feasibility for HSA. The self-assembly process on quartz is followed by UV-vis spectroscopy (data not shown here). The absorbance of the film increases regularly with increasing bi...

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