Molecular rotors have played an important role in recent materials chemistry. Although several studies on functional materials containing molecular rotors have been reported for fluorescence sensing, ...this concept has yet to be realized in two-dimensional (2D) materials. Here we report the preparation of all-carbon, π-conjugated 2D porous organic nanosheets, named NUS-24, which contain flexible tetraphenylethylene (TPE) units as the molecular rotors. NUS-24 nanosheets exhibit high stability, large lateral size, and ultrathin thickness (2-5 nm). The dynamic TPE rotors exposed on the surface of NUS-24 nanosheets can be restricted in the aggregated state with different water fractions, which is reminiscent of the aggregation-induced emission mechanism, thereby leading to the size-selective turn-on fluorescence by volatile organic compounds. Significantly, the ultrathin 2D nanosheets and its composite membranes show much higher sensitivity and selectivity toward Fe
ions and nitro-containing compounds sensing, suggesting their potential applications in explosive detection and environmental monitoring.
A new type of core-shell upconversion nanoparticles which can be effectively excited at 795 nm has been designed and synthesized through spatially confined doping of neodymium (Nd(3+)) ions. The use ...of Nd(3+) ions as sensitizers facilitates the energy transfer and photon upconversion of a series of lanthanide activators (Er(3+), Tm(3+), and Ho(3+)) at a biocompatible excitation wavelength (795 nm) and also significantly minimizes the overheating problem associated with conventional 980 nm excitation. Importantly, the core-shell design enabled high-concentration doping of Nd(3+) (~0 mol %) in the shell layer and thus markedly enhanced the upconversion emission from the activators, providing highly attractive luminescent biomarkers for bioimaging without autofluorescence and concern of overheating.
Aiming at the construction of novel circularly polarized luminescence (CPL) switches with multiple switchable emission states and high dissymmetry factors (glum), topologically chiral 2catenanes were ...employed as the key platform to construct a novel multistate CPL switching system. Taking advantage of the precise co‐conformation regulations of the resultant pyrene‐functionalized 2catenanes under different external stimuli, reversible transformations between three emission states with different CPL performances, i.e. the initial “closed” form with a |glum| value of 0.012, the “open” form with an almost complete turn‐off of CPL emission, and the “protonated” form with a boosted |glum| value of 0.022, were successfully realized. This study demonstrates the successful construction of not only the first topological chirality‐based CPL switch, but also a novel bidirectional CPL switch, thus providing a promising platform for the construction of novel chiral materials.
By using topologically chiral 2catenanes as not only the chiral platform but also the switching scaffold, the first construction of a novel bidirectional circularly polarized luminescence switching system was successfully realized.
A persistent challenge in classical photocatalyst systems with extended light absorption is the unavoidable trade‐off between maximizing light harvesting and sustaining high photoredox capability. ...Alternatively, cooperative energy conversion through photothermic activation and photocatalytic redox is a promising yet unmet scientific proposition that critically demands a spectrum‐tailored catalyst system. Here, we construct a solar thermal‐promoted photocatalyst, an ultrathin “biphasic” ordered–disordered D‐HNb3O8 junction, which performs two disparate spectral selective functions of photoexcitation by ordered structure and thermal activated conversion via disordered lattice for combinatorial photothermal mediated catalysis. This in situ synthetically immobilized lattice distortion, constrained to a single‐entity monolayer structure not only circumvents interfacial incompatibility but also triggers near‐field temperature rise at the catalyst–reactant complexes’ proximity to promote photoreaction. Ultimately, a generic full solar conversion improvement for H2 fuel production, organic transformation and water purification is realized.
Let the sunshine in: Single‐entity ordered–disordered monolayer D‐HNb3O8 nanosheets were engineered to realize full solar spectrum (250–2500 nm) utilization. The crystalline domains absorb UV photons to generate charge carriers, while the disordered “nanoislands” capture the full spectrum for solar heating to thermally boost the reaction kinetics.
Partial least squares (PLS) have gained wide applications especially in chemometrics, metabolomics/metabonomics as well as bioinformatics. Here, we present libPLS, a library that integrates not only ...basic PLS modeling algorithms but also advanced and/or recently developed methods on model assessment, outlier detection, and variable selection. This package is featured in a set of Model Population Analysis (MPA)-type approaches that have not been integrated into a single package yet and thus functionally complement existing toolboxes. libPLS provides an integrated platform for developing PLS regression and/or linear discriminant analysis (PLS-LDA) models. It is written in MATLAB and freely available at www.libpls.net.
•Provide an integrated library for partial least squares regression and discriminant analysis.•Featured in model population analysis approaches.•Contain a series of versatile variable selection methods.
We disclose an efficient and operationally simple protocol for the preparation of fused N‐heterocycles starting from readily available 2‐nitrobiaryls and PhMgBr under mild conditions. More than two ...dozen N‐heterocycles, including two bioactive natural products, have been synthesized using this method. A stepwise electrophilic aromatic cyclization mechanism was proposed by DFT calculations.
Controlled fusion: A transition‐metal‐free, low‐temperature, and regioselective intramolecular amination of aromatic C(sp2)H bonds provides fused N‐heterocycles. This reaction is operationally simple and scalable (1–10 mmol) and the scope of substrates is wide (see scheme). Density functional calculations indicate that a stepwise electrophilic aromatic cyclization mechanism may be operative.
At present, the technological groundwork of atomically thin two-dimensional (2D) hetero-layered structures realized by successive thin film epitaxial growth is in principle constrained by lattice ...matching prerequisite as well as low yield and expensive production. Here, we artificially coordinate ultrathin 2D hetero-layered metal chalcogenides via a highly scalable self-surface charge exfoliation and electrostatic coupling approach. Specifically, bulk metal chalcogenides are spontaneously exfoliated into ultrathin layers in a surfactant/intercalator-free medium, followed by unconstrained electrostatic coupling with a dissimilar transition metal dichalcogenide, MoSe
, into scalable hetero-layered hybrids. Accordingly, surface and interfacial-dominated photocatalysis reactivity is used as an ideal testbed to verify the reliability of diverse 2D ultrathin hetero-layered materials that reveal high visible-light photoreactivity, efficient charge transfer and intimate contact interface for stable cycling and storage purposes. Such a synthetic approach renders independent thickness and composition control anticipated to advance the development of 'design-and-build' 2D layered heterojunctions for large-scale exploration and applications.
Two-photon photodynamic therapy (2P-PDT) is a novel minimal invasive cancer treatment method with advantages of deep penetration and intrinsic three-dimensionally localized activation to precisely ...target cancerous tissues. However, the therapeutic efficacy of 2P-PDT is limited by small two-photon absorption cross sections of conventional organic photosensitizers. In addition, traditional photosensitizers generally exhibit weak emission and lack imaging modality. In this work, conjugated polymers and gold nanorods (Au NRs) were integrated to fabricate nano-sized photosensitizers to improve the performance of molecular photosensitizers for 2P-PDT. A molecular photosensitizer, tetraphenylporphyrin, was encapsulated into the conjugated polymer PFV to form conjugated polymer nanoparticles (CPNs), which were then covalently linked to silica coated Au NRs. In these integrated nanoparticles, the two-photon optical properties of tetraphenylporphyrin were first enhanced by fluorescence resonance energy transfer from PFV, then further enhanced by Au NRs through plasmon resonance. A silica shell was utilized as the spacer between Au NRs and CPNs to optimize the enhancement effects. Through the combined enhancement effects of energy transfer and plasmon resonance, two-photon excitation fluorescence and two-photon induced singlet oxygen generation of tetraphenylporphyrin were enhanced by up to 980- and 792-fold, respectively, at a silica spacer thickness of 9 nm. The application of these nanoparticles as photosensitizers for simultaneous two-photon imaging and 2P-PDT treatment have been demonstrated on HeLa cancer cells with high brightness and significantly enhanced cancer cell killing efficiency. These nanoparticles can act as promising nano-photosensitizers for 2P-PDT with simultaneous imaging modality.
A copper(II) acetate/(R)‐DTBM‐SEGPHOS‐catalyzed ring opening of benzofurans and enantioselective hydroamination cascade with dimethoxymethylsilane (DMMS) and hydroxylamine esters is described. ...Starting from readily available substituted benzofurans, a series of chiral N,N‐dibenzylaminophenols, which are of high interest in pharmaceutical chemistry, were obtained with excellent enantioselectivities (up to 66 % yield, 94 % ee).
Opening up: A copper(II) acetate/(R)‐DTBM‐SEGPHOS‐catalyzed ring opening of benzofurans and an enantioselective hydroamination cascade with dimethoxymethylsilane (DMMS) and hydroxylamine esters is described. Starting from readily available substituted benzofurans, a series of chiral N,N‐dibenzylaminophenols, which are of high interest in pharmaceutical chemistry, were obtained with excellent enantioselectivity.
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•Circular RNAs in human HCC were identified using RNA-sequencing.•Circular RNA cSMARCA5 was downregulated in HCC and associated with poor prognosis.•Downregulation of cSMARCA5 in HCC ...was attributed to the upregulation of DHX9.•cSMARCA5 inhibited HCC growth and metastasis both in vitro and in vivo.•cSMARCA5 acted as the sponge of miR-17-3p and miR-181b-5p to upregulate TIMP3.
In recent years, circular RNAs (circRNAs) have been shown to have critical regulatory roles in cancer biology. However, the contributions of circRNAs to hepatocellular carcinoma (HCC) remain largely unknown.
cSMARCA5 (a circRNA derived from exons 15 and 16 of the SMARCA5 gene, hsa_circ_0001445) was identified by RNA-sequencing and validated by quantitative reverse transcription PCR. The role of cSMARCA5 in HCC progression was assessed both in vitro and in vivo. circRNAs in vivo precipitation, luciferase reporter assay, biotin-coupled microRNA capture and fluorescence in situ hybridization were conducted to evaluate the interaction between cSMARCA5 and miR-17-3p/miR-181b-5p.
The expression of cSMARCA5 was lower in HCC tissues, because of the regulation of DExH-Box Helicase 9, an abundant nuclear RNA helicase. The downregulation of cSMARCA5 in HCC was significantly correlated with aggressive characteristics and served as an independent risk factor for overall survival and recurrence-free survival in patients with HCC after hepatectomy. Our in vivo and in vitro data indicated that cSMARCA5 inhibits the proliferation and migration of HCC cells. Mechanistically, we found that cSMARCA5 could promote the expression of TIMP3, a well-known tumor suppressor, by sponging miR-17-3p and miR-181b-5p.
These results reveal an important role of cSMARCA5 in the growth and metastasis of HCC and provide a fresh perspective on circRNAs in HCC progression.
Herein, we studied the role of cSMARCA5, a circular RNA, in hepatocellular carcinoma. Our in vitro and in vivo data showed that cSMARCA5 inhibits the growth and migration of hepatocellular carcinoma cells, making it a potential therapeutic target.
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