Showing papers by "Wei Jiang published in 2016"
TL;DR: In this article, a poly(e-caprolactone) (PCL)/poly(lactic acid) (PLA) blend is achieved through the adsorption-desorption of polymer chains on the graphene surface.
112 citations
TL;DR: It is found that two molecular tubes with inwardly directed hydrogen-bond donors recognize highly hydrophilic solvent molecules in water with high selectivity.
Abstract: Selective recognition of neutral hydrophilic molecules in water is a challenge for supramolecular chemistry but commonplace in nature. By mimicking the binding pocket of natural receptors, endo-functionalized molecular tubes are proposed to meet this challenge. We found that two molecular tubes with inwardly directed hydrogen-bond donors recognize highly hydrophilic solvent molecules in water with high selectivity. In the complexes, hydrogen bonding occurs in the deep and hydrophobic cavity. The cooperative action between hydrogen bonding and hydrophobic effects accounts for the high affinity and selectivity. The molecular receptor is fluorescent and can detect concentrations of 1,4-dioxane—a known carcinogen and persistent environmental contaminant—in water at a limit of 119 ppb. The method simplifies the analytic procedure for this highly hydrophilic molecule.
105 citations
TL;DR: The molecular "transformer", oxatub[4]arene, was found to be able to host a wide range of organic cations and its strong binding ability is believed to originate from its four interconvertible and deep-cavity conformers.
41 citations
TL;DR: The tensile toughness of PLA/PPC-MA blends was significantly improved with the addition of TBT when the poly(lactic acid) content was higher than 50 wt % as discussed by the authors.
Abstract: Poly(lactic acid) (PLA) and maleic acid anhydride end-capped poly(propylene carbonate) (PPC-MA) were melt blended with or without transesterification catalyst tetrabutyl titanate (TBT). The gel permeation chromatography (GPC), dynamic mechanical analysis (DMA) and differential scanning calorimetry (DSC) results indicated that the addition of TBT promoted the transesterification and the transesterification degree increased with increasing the TBT content. The scanning electron microscopy (SEM) photographs showed that the PLA/PPC-MA/TBT could be plastic stretched deeply under tensile stress. Moreover, PPC-MA was more active than PLA in the catalytic transesterification and the weight percent of PPC-MA had obvious effects on the mechanical properties of the blends. The tensile toughness of PLA/PPC-MA blends was significantly improved with the addition of TBT when the PPC-MA content was higher than 50 wt %.
41 citations
TL;DR: Four endo-functionalized molecular tubes with urea/thiourea groups in the deep cavities have been synthesized, and their binding ability to neutral molecules studied, achieving very high binding affinity and selectivity.
35 citations
TL;DR: In this article, the authors discussed the recent advances on naphthol-based macrocyclic receptors, with special emphasis on the construction of NPHthol based molecular receptors with high guest binding ability and selectivity, and broad guest binding scope.
33 citations
TL;DR: The current study implies that self-assembled nanostructures under 3D soft confinement can be simply controlled by tuning the confinement degree and interfacial property, i.e., the ratio of D/L and the interfacial interaction between each individual block and boundary interface.
Abstract: The self-assembly of AB-type diblock copolymers confined in a three-dimensional (3D) soft nanodroplet is investigated by the combination of Monte Carlo simulation and experiment. The influences of two critical factors, i.e., confinement degree of the imposed confinement space and the interfacial interaction between each individual block and boundary interface, on the 3D soft confined self-assembly are examined systematically. The simulation results reveal that block copolymer chains become more and more folded as the confinement degree (it can be monitored by the ratio of D/L, where L is the length of polymer chain and D is the reduced diameter of the final polymeric particle) is enhanced, causing a series of morphological transitions. Based on the simulation prediction, we perform the corresponding experiments by the 3D confined self-assembly of both symmetric and asymmetric block copolymers within the emulsion droplets. The experimental results well reproduce the confinement degree induced morphological...
32 citations
TL;DR: A new way of exploring metabolic mechanism of functional genes and engineering whole cell-catalysts for synthesis of chiral α-hydroxy acids or chiral amino acids is paved by connecting protein-protein expressions and regulating the strength of ribosome binding sites.
Abstract: Systems that can regulate and coordinate the expression of multiple enzymes for metabolic regulation and synthesis of important drug intermediates are poorly explored. In this work, a strategy for constructing a tunable multi-enzyme-coordinate expression system for biosynthesis of chiral drug intermediates was developed and evaluated by connecting protein-protein expressions, regulating the strength of ribosome binding sites (RBS) and detecting the system capacity for producing chiral amino acid. Results demonstrated that the dual-enzyme system had good enantioselectivity, low cost, high stability, high conversion rate and approximately 100% substrate conversion. This study has paved a new way of exploring metabolic mechanism of functional genes and engineering whole cell-catalysts for synthesis of chiral α-hydroxy acids or chiral amino acids.
29 citations
28 citations
TL;DR: A series of acceptor-donor-acceptor (A-D-A) conjugated molecules based on naphthalene diimide dimers bridged with different π-conjugated heterocyclic units (NDI-π-NDI) have been designed and synthesized as discussed by the authors.
Abstract: A series of acceptor–donor–acceptor (A–D–A) conjugated molecules based on naphthalene diimide dimers bridged with different π-conjugated heterocyclic units (NDI–π–NDI) have been designed and synthesized. By an ingenious design strategy, the LUMO (the lowest unoccupied molecular orbital) of the NDI-based small molecules is well controlled to a relatively constant value of −3.8 to −3.9 eV, whereas their HOMO (the highest occupied molecular orbital) could be tuned over a wide range, from −6.5 eV (compound 1) to −5.5 eV (compound 5), leading to varied band gaps from 2.6 eV to 1.5 eV. Organic field-effect transistor (OFET) characterization of these NDI–π–NDI molecules shows that compounds 1, 2, and 3 have good n-type semiconducting properties in a N2 atmosphere with the maximum electron mobilities up to 0.15 cm2 V−1 s−1, 0.46 cm2 V−1 s−1 and 0.57 cm2 V−1 s−1, respectively. Compounds 4 and 5, due to the high-lying HOMO levels and reduced energy band gaps, have ambipolar semiconducting properties and OFETs based on 5 show the highest electron and hole mobilities up to 1.23 cm2 V−1 s−1 and 0.0074 cm2 V−1 s−1, respectively. Moreover, the performances are enhanced under thermal treatment because of the increased crystallinity as evidenced by X-ray diffraction (XRD) and atomic force microscopy (AFM). The easily tunable electronic energy levels make the NDI-based semiconductors promising n-channel and ambipolar components in organic devices.
26 citations
TL;DR: Experimental results indicated that the conformation and orientation of the absorbed Fibs depended on surface property and pH cycling, and integrin adhesion was more likely to occur, and more platelets were adhered and activated.
Abstract: Quartz crystal microbalance with dissipation (QCM-D) and dual polarization interferometry (DPI) were used to investigate fibrinogen (Fib) adsorption behavior on different surfaces by changing the pH value. Moreover, integrin adhesion to the adsorbed Fibs was studied using DPI. Qualitative and quantitative studies of platelet adhesion to the adsorbed Fibs were performed using scanning electron microscopy (SEM), confocal laser scanning microscope (CLSM), and released lactate dehydrogenase (LDH) assay. Experimental results indicated that the conformation and orientation of the absorbed Fibs depended on surface property and pH cycling. For the hydrophilic surface, Fibs adsorbed at pH 7.4 and presented a αC-hidden orientation. As a result, no integrin adhesion was observed, and a small number of platelets were adhered because the αC-domains were hidden under the Fib molecule. By changing the rinsing solution pH from 7.4 to 3.2 and then back to 7.4, the adsorbed Fib orientation became αC-exposed via the transformation of Fib conformation during pH cycling. Therefore, integrin adhesion was more likely to occur, and more platelets were adhered and activated. For the hydrophobic surface, the adsorbed Fibs became more spread and stretched due to the strong interaction between the Fibs and surface. αC-exposed orientation remained unchanged when the rinsing solution pH changed from 7.4 to 3.2 and then back to 7.4. Therefore, a large number of integrins and platelets were adhered to the adsorbed Fibs, and almost all of the adhered platelets were activated.
TL;DR: It is found that ABC triblock copolymers usually aggregate into a loose aggregate at first, and then the microphase separation between A, B and C blocks occurs, resulting in the formation of various nanostructures.
Abstract: Under three-dimensional (3D) soft confinement, block copolymers can self-assemble into unique nanostructures that cannot be fabricated in an un-confined space. Linear ABC triblock copolymers containing three chemically distinct polymer blocks possess relatively complex chain architecture, which can be a promising candidate for the 3D confined self-assembly. In the current study, the Monte Carlo technique was applied in a lattice model to study the self-assembly of ABC triblock copolymers under 3D soft confinement, which corresponds to the self-assembly of block copolymers confined in emulsion droplets. We demonstrated how to create various nanostructures by tuning the symmetry of ABC triblock copolymers, the incompatibilities between different block types, and solvent properties. Besides common pupa-like and bud-like nanostructures, our simulations predicted various unique self-assembled nanostructures, including a striped-pattern nanoparticle with intertwined A-cages and C-cages, a pyramid-like nanoparticle with four Janus B–C lamellae adhered onto its four surfaces, an ellipsoidal nanoparticle with a dumbbell-like A-core and two Janus B–C lamellae and a Janus B–C ring surrounding the A-core, a spherical nanoparticle with a A-core and a helical Janus B–C stripe around the A-core, a cubic nanoparticle with a cube-shape A-core and six Janus B–C lamellae adhered onto the surfaces of the A-cube, and a spherical nanoparticle with helical A, B and C structures, from the 3D confined self-assembly of ABC triblock copolymers. Moreover, the formation mechanisms of some typical nanostructures were also examined by the variations of the contact numbers with time and a series of snapshots at different Monte Carlo times. It is found that ABC triblock copolymers usually aggregate into a loose aggregate at first, and then the microphase separation between A, B and C blocks occurs, resulting in the formation of various nanostructures.
TL;DR: The TF-miRNA-gene network in esophageal cancer was established, summarizing the regulatory links among the TFs, differentially expressed miRNAs and differentially expression genes.
Abstract: In this study, we explored the gene and microRNA (miRNA) expressions profile of esophageal carcinoma. The expression data for messenger RNAs and miRNAs in normal and cancerous esophageal tissues were obtained from the Cancer Genome Atlas database and then the differentially expressed genes and miRNAs were identified. As a result, we identified 2962 genes and 45 miRNAs differentially expressed in esophageal carcinoma compared with normal esophageal tissues. Subsequently, the altered gene functions and signaling pathways were investigated using gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses, and these differentially expressed genes were significantly enriched in the cell cycle, cell migration, mitogen-activated protein kinase (MAPK) and toll-like receptor signaling pathway, and so on. Then the regulatory relationships between the differentially expressed miRNAs and genes were examined with Targetscan and Miranda, and the potential target sites of transcription factors (TFs) in the promoter regions of these miRNAs and genes were identified using the TRANSFAC database. Finally the TF-miRNA-gene network in esophageal cancer was established, summarizing the regulatory links among the TFs, differentially expressed miRNAs and differentially expressed genes. Factors such as core promoter-binding protein (CPBP), nuclear factor of activated T-cells 1 (NFAT-1), miR-30c-5p, were located in the central hub of this network, highlighting their vital roles in esophageal tumorigenesis. These findings may extend our understanding of the molecular mechanisms underlying esophageal carcinoma and promote new perspectives for prevention, diagnosis and treatment.
TL;DR: In this article, a set of non-fullerene small molecules based on bis(perylene diimide) with DACH bridge was designed, synthesized, and characterized.
Abstract: In this paper, we designed, synthesized, and characterized a set of non-fullerene small molecules based on bis(perylene diimide) with DACH bridge. Theoretical calculations make clear that the introduction of the DACH bridge into PPDI forms a U-shape framework, with pi–pi interactions between PDIs. We investigate the performances of non-fullerene solar cells comprising racemic and enantiomerically pure DACH-PPDIs as the electron acceptor and PTB7-Th as the electron donor. As a consequence, a power conversion efficiency (PCE) of 4.68% is achieved with inverted device architecture. Furthermore, the device behaviour, morphological feature and charge transport properties were also investigated. It is a potential way to design highly efficient non-fullerene organic solar cell by tuning the structure of PDI to reach highly efficient photovoltaic performances.
TL;DR: In this article, a thermoplasticized crosslinked starch (TPCLS) was melt-compounded with polylactide (PLA) and poly(ether-block-amide) (PEBA) to prepare biodegradable PLA/PEBA/ TPCLS blend with high impact resistance.
Abstract: Corn starch was crosslinked with epichlorohydrin (ECH) and then plasticized with glycerol. Subsequently, this thermoplasticized crosslinked starch (TPCLS) was melt-compounded with polylactide (PLA) and poly(ether-block-amide) (PEBA) to prepare biodegradable PLA/PEBA/TPCLS blend with high impact resistance. It was found that the crosslinking agent ECH had critical effect on the impact strength, tensile properties, and internal morphology of the ternary blend. The impact strength, tensile strength, and elongation at break increased with ECH content; thereafter, they decreased on further increasing the ECH content. At 0.5 wt % ECH content, impact strength, tensile strength, and elongation at break reached the maximum values and smaller salami structure particles were observed accordingly. These results were attributed to the competition of shear resistance of TPCLS and the chemical linkage between the crosslinked starch and PLA-g-MA. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 42297.
TL;DR: A dewetting-induced assembly strategy for obtaining large-scale and highly oriented organic crystal arrays and demonstrates that organic field-effect transistors (OFETs) fabricated from patterned n-alkyl-substituted tetrachloroperylene diimide (R-4ClPDI) single crystals can reach a maximum mobility in ambient conditions.
Abstract: Simple methods for patterning single crystals are critical to fully realize their applications in electronics. However, traditional vapor and solution methods are deficient in terms of crystals with random spatial and quality distributions. In this work, we report a dewetting-induced assembly strategy for obtaining large-scale and highly oriented organic crystal arrays. We also demonstrate that organic field-effect transistors (OFETs) fabricated from patterned n-alkyl-substituted tetrachloroperylene diimide (R–4ClPDI) single crystals can reach a maximum mobility of 0.65 cm2 V–1 s–1 for C8–4ClPDI in ambient conditions. This technique constitutes a facile method for fabricating OFETs with high performances for large-scale electronics applications.
TL;DR: Interestingly, the same morphology of the self-assembled aggregates can be obtained either at high H(+) addition or at low OH(-) addition, which results from the nonmonotonic variation of the intercorona interaction along with the addition of HCl or NaOH.
Abstract: The cooperative self-assembly of amphiphilic polystyrene-block-poly(acrylic acid) (PS144-b-PAA22) and polystyrene-block-poly(4-vinylpyridine) (PS144-b-P4VP33) diblock copolymers in DMF/H2O mixtures has been investigated. Both copolymers self-assemble into small spherical micelles (SSMs) if used individually. However, the equimolar mixture of these two copolymers cooperatively self-assembles into vesicles. It is found that the formation of vesicles is attributed to the complex interactions between PAA and P4VP chains, including the hydrogen bonds between un-ionized acrylic acid units and pyridine units as well as the electronic attractions between ionized acrylic acid units and protonated pyridine units. Since these interactions between PAA and P4VP chains depend on pH value, the cooperatively self-assembled morphology can be easily tuned by the addition of HCl or NaOH. At high addition of H(+) or OH(-), the intercorona interaction is repulsive and the copolymer mixture tends to form SSMs (basic condition) or cylindrical micelles (acidic condition), whereas it prefers to aggregate into vesicles at low addition of H(+) or OH(-) because the intercorona interaction is attractive. Interestingly, the same morphology of the self-assembled aggregates can be obtained either at high H(+) addition or at low OH(-) addition, which results from the nonmonotonic variation of the intercorona interaction along with the addition of HCl or NaOH. The current study implies that it is the intercorona interaction rather than the chemical condition that dominates the cooperatively self-assembled morphology.
TL;DR: In this paper, the gamma-ray emission from the Milky Way satellites was analyzed to search for potential line signals due to the annihilation of dark matter particles into double photons, and the corresponding upper limits on the cross section of DM annihilation into two photons were derived.
Abstract: With 91 months of the publicly available Fermi LAT Pass 8 data, we analyze the gamma-ray emission from the Milky Way satellites to search for potential line signals due to the annihilation of dark matter particles into double photons. The searched targets include a sample of dwarf spheroidal galaxies, the Large Magellanic Cloud (LMC) and the Small Magellanic Cloud (SMC). No significant line emission has been found in the stacked dwarf galaxy sample or in the direction of LMC/SMC. The corresponding upper limits on the cross section of DM annihilation into two photons are derived. Compared with results of previous gamma-ray line searches with the Pass 7 data, the current constraints on the line emission from dwarf spheroidal galaxies have been significantly improved in a wide energy range. With the rapid increase of the sample of dwarf spheroidal galaxies (candidates), we expect that the sensitivity of gamma-ray line searches will be significantly improved in the near future.
TL;DR: In this paper, the authors investigated the reversible transition of self-assembly and disassembly for PS 720 -P2VP 200 -PEO 375 multicompartment micelles in aqueous solution induced solely by changing temperature.
TL;DR: The Monte Carlo simulation results indicate that the hydrophilicity of the end-grafted polymers can affect both the amount and speed of protein adsorption.
TL;DR: It is found that the number of degenerate structures decreases, that is, only blocky structures can be obtained in the case of high NP content, and analysis of the interactive enthalpy densities and the chain conformation of the systems indicates that entropy plays an important role in the degenerate structure formation.
Abstract: Degenerate behavior (i.e., forming different self-assembled structures for a given block copolymer (BCP) under the same confinement) commonly exists in various confined systems. Understanding degenerate behavior is crucial for precise control over the structures formed by self-assembly systems under confinement. In this study, the degenerate behavior of a self-assembled AB diblock copolymer/nanoparticle (NP) mixture in a cylindrical pore is studied using Monte Carlo simulation. We find that the degenerate behavior of such a mixture depends on the introduction of the NP. Under different pore sizes, four typical degenerate structures [i.e., single helices (S-helices), double helices (D-helices), parallel cylinders, and stacked toroids] can be obtained if the NP content is zero. However, when the NP content in the mixture is increased, it is found that the number of degenerate structures decreases, that is, only blocky structures can be obtained in the case of high NP content. Moreover, the probability of fo...
TL;DR: In this article, the effect of the position of the branching point on the film microstructure and charge transport was studied in detail, and the results demonstrate that the different branching point of side-chains has a negligible effect on the absorption maximum and energy gap.
Abstract: The alkyl chain length and density are fundamental factors affecting solution processability, molecular packing, film microstructure, and charge transport for organic thin film transistors (OTFTs). In this work, four tetra-chlorinated di(perylene diimides) 4CldiPDI-C(1–4) were prepared through moving the alkyl chain branching position away from the di(perylene diimides) backbone. OTFT devices employing 4CldiPDI-C(1–4) as the active layer were fabricated. Correspondingly, the effect of the position of the alkyl chain branching point on the film microstructure and charge transport were studied in detail. The research results demonstrate that the different branching point of side-chains has a negligible effect on the absorption maximum and energy gap. Conversely, the gradual movement in the branching point plays a key role in molecular packing and leads to a clear impact on electron mobility ranging from 0.012 to 0.86 cm2 V−1 s−1. Therefore, 4CldiPDI-C2-based devices offered the highest electron mobility of up to 0.86 cm2 V−1 s−1 and an on/off ratio of 2 × 107, which is among the best performance of diPDI derivatives.
TL;DR: Here, a slower cooling rate is used after the CVD process, and the graphene films are found to have an improved electrical performance, which is considered to be associated with the Cu surface evaporation and grain structure changes in the Cu substrate.
Abstract: During the chemical vapor deposition (CVD) growth of graphene on Cu foils, evaporation of Cu and changes in the dimensions of Cu grains in directions both parallel and perpendicular to the foils are induced by thermal effects. Such changes in the Cu foil could subsequently change the shape and distribution of individual graphene domains grown on the foil surface, and thus influence the domain structure and electrical properties of the resulting graphene films. Here, a slower cooling rate is used after the CVD process, and the graphene films are found to have an improved electrical performance, which is considered to be associated with the Cu surface evaporation and grain structure changes in the Cu substrate.
TL;DR: The solution-phase photooxygenation of multiply threaded crown/ammonium pseudorotaxanes containing anthracene spacers is monitored by electrospray ionization Fourier-transform ion-cyclotron-resonance (ESI-FTICR) mass spectrometry.
Abstract: The solution-phase photooxygenation of multiply threaded crown/ammonium pseudorotaxanes containing anthracene spacers is monitored by electrospray ionization Fourier-transform ion-cyclotron-resonance (ESI-FTICR) mass spectrometry. The oxygenated pseudorotaxanes are mass-selected and fragmented by infrared multiphoton dissociation (IRMPD) and/or collision-induced dissociation (CID) experiments and and their behavior compared to that of the non-oxygenated precursors. [4+2]Cycloreversion reactions lead to the loss of O2, when no other reaction channel with competitive energy demand is available. Thus, the release of molecular oxygen can serve as a reference reaction for the energy demand of other fragmentation reactions such as the dissociation of the crown/ammonium binding motifs. The photooxygenation induces curvature into the initially planar anthracene and thus significantly changes the geometry of the divalent, anthracene-spacered wheel. This is reflected in ion-mobility data. Coulomb repulsion in multiply charged pseudorotaxanes assists the oxygen loss as the re-planarization of the anthracene increases the distance between the two charges.
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TL;DR: In this article, a software framework has been developed for the DArk Matter Particle Explorer (DAMPE) mission, a satellite based experiment, which consists of four principal parts: event data module which contains all reconstruction and simulation information based on ROOT input/output (I/O) streaming; a collection of processing models which are used to process each event data; service module, a series of common tools which provide general functionalities like data communication between algorithms; and event filters.
Abstract: A software framework has been developed for the DArk Matter Particle Explorer (DAMPE) mission, a satellite based experiment. The software framework of DAMPE is mainly written in C++, while the application under this framework is steered in Python script. The framework is comprised of four principal parts: event data module which contains all reconstruction and simulation information based on ROOT input/output (I/O) streaming; a collection of processing models which are used to process each event data, called as algorithms; service module, a series of common tools which provide general functionalities like data communication between algorithms; and event filters. This article presents an overview of the DAMPE offline software framework, and the major architecture design choices during the development. The whole system has been applied to DAMPE data analysis successfully, based on which some results from simulation and beam test experiments are also shown in this article.
TL;DR: In this paper, the authors discussed the recent advances on naphthol-based macrocyclic receptors, with special emphasis on the construction of NPHthol based molecular receptors with high guest binding ability and selectivity, and broad guest binding scope.
Abstract: Synthetic macrocyclic receptors are the primary workhorses in supramolecular chemistry. In particular, macrocyclic arenes are versatile receptors due to their special binding performances and wide applications. In this Digest, we discussed the recent advances on naphthol-based macrocyclic receptors, with special emphasis on the construction of naphthol-based molecular receptors with high guest binding ability and selectivity, and broad guest binding scope.