Polymerization and isomerization cyclic amplification for nucleic acid detection with attomolar sensitivity.

DNA amplification is one of the most valuable tools for the clinical diagnosis of nucleic acid-related diseases, but current techniques for DNA amplification are based on intermolecular polymerization reactions, resulting in the risk of errors in the intermolecular reaction pattern. In this article, we introduce the concept of intramolecular polymerization and isomerization cyclic amplification (PICA), which extends a short DNA strand to a long strand containing periodic repeats of a sequence through cyclic alternating polymerization and isomerization. To the best of our knowledge, this is the first time that a real ssDNA self-extension method without any additional auxiliary oligonucleotides has been reported.

A bipedal DNA nanowalker fueled by catalytic assembly for imaging of base-excision repairing in living cells.

DNA nanowalkers moving progressively along a prescribed DNA track are useful tools in biosensing, molecular theranostics and biosynthesis. However, stochastic DNA nanowalkers that can perform in living cells have been largely unexplored. We report the development of a novel stochastic bipedal DNA walker that, for the first time, realizes direct intracellular base excision repair (BER) fluorescence activation imaging.

Construction of coacervate-in-coacervate multi-compartment protocells for spatial organization of enzymatic reactions.

Coacervate microdroplets, formed liquid-liquid phase separation, have been extensively explored as a compartment model for the construction of artificial cells or organelles. In this study, coacervate-in-coacervate multi-compartment protocells were constructed using four polyelectrolytes, in which carboxymethyl-dextran and diethylaminoethyl-dextran were deposited on the surface of as-prepared polydiallyldimethyl ammonium/deoxyribonucleic acid coacervate microdroplets through layer-by-layer assembly. The resulting multi-compartment protocells were composed from two immiscible coacervate phases with distinct physical and chemical properties.

Engineering a highly selective probe for ratiometric imaging of HS and revealing its signaling pathway in fatty liver disease.

Hydrogen polysulfides (HS , > 1) have continuously been proved to act as important signal mediators in many physiological processes. However, the physiological role of HS and their signaling pathways in complex diseases, such as the most common liver disease, nonalcoholic fatty liver disease (NAFLD), have not been elucidated due to lack of suitable tools for selective detection of intracellular HS . Herein, we adopted a general and practical strategy including recognition site screening, construction of a ratiometric probe and self-assembly of nanoparticles, to significantly improve the probes' selectivity, photostability and biocompatibility.

An Investigation of Active Sites for electrochemical CO Reduction Reactions: From In Situ Characterization to Rational Design.

The electrochemical carbon dioxide (CO) reduction reaction (CORR) is among the most promising approaches used to transform greenhouse gas into useful fuels and chemicals. However, the reaction suffers from low selectivity, high overpotential, and low reaction rate. Active site identification in the CORR is vital for the understanding of the reaction mechanism and the rational development of new electrocatalysts with both high selectivity and stability.

Schottky Junctions with Bi Cocatalyst for Taming Aqueous Phase N Reduction toward Enhanced Solar Ammonia Production.

Solar-powered N reduction in aqueous solution is becoming a research hotspot for ammonia production. Schottky junctions at the metal/semiconductor interface have been effective to build up a one-way channel for the delivery of photogenerated electrons toward photoredox reactions. However, their applications for enhancing the aqueous phase reduction of N to ammonia have been bottlenecked by the difficulty of N activation and the competing H evolution reaction (HER) at the metal surface.

Chemical vapor deposition and temperature-dependent Raman characterization of two-dimensional vanadium ditelluride.

Recently, ultrathin two-dimensional (2D) metallic vanadium dichalcogenides have attracted widespread attention because of the charge density wave (CDW) phase transition and possible ferromagnetism. Herein, we report the synthesis and temperature-dependent Raman characterization of the 2D vanadium ditelluride (VTe). The synthesis is done by atmospheric pressure chemical vapor deposition (APCVD) using vanadium chloride (VCl) precursor on fluorphlogopite mica, sapphire, and h-BN substrates.

Seamlessly Splicing Metallic Sn Mo S at MoS Edge for Enhanced Photoelectrocatalytic Performance in Microreactor.

Accurate design of the 2D metal-semiconductor (M-S) heterostructure via the covalent combination of appropriate metallic and semiconducting materials is urgently needed for fabricating high-performance nanodevices and enhancing catalytic performance. Hence, the lateral epitaxial growth of M-S Sn Mo S/MoS heterostructure is precisely prepared with in situ growth of metallic Sn Mo S by doping Sn atoms at semiconductor MoS edge via one-step chemical vapor deposition. The atomically sharp interface of this heterostructure exhibits clearly distinguished performance based on a series of characterizations.

Carbon Dots@rGO Paper as Freestanding and Flexible Potassium-Ion Batteries Anode.

Carbonaceous materials, especially with graphite-layers structure, as anode for potassium-ion batteries (PIBs), are the footstone for industrialization of PIBs. However, carbonaceous materials with graphite-layers structure usually suffer from poor cycle life and inferior stability, not to mention freestanding and flexible PIBs. Here, a freestanding and flexible 3D hybrid architecture by introducing carbon dots on the reduced graphene oxide surface (CDs@rGO) is synthesized as high performance PIBs anode.

Atom-efficient synthesis of 2,4,6-trisubstituted 1,3,5-triazines Fe-catalyzed cyclization of aldehydes with NHI as the sole nitrogen source.

An atom-efficient, straightforward method for the synthesis of 2,4,6-triaryl-1,3,5-triazines iron-catalyzed cyclization of aldehydes with NHI as the sole nitrogen source is demonstrated. This strategy works smoothly under air atmosphere, and affords symmetrical 2,4,6-trisubstituted and unsymmetrical 1,3,5-triazines with yields from 18% to 72%. Compared to other methods, the present protocol provides a straightforward and atom-efficient approach to 2,4,6-trisubstituted 1,3,5-triazines using an inexpensive, easily available ammonium salt as the sole nitrogen source.

Direct cyanation, hydrocyanation, dicyanation and cyanofunctionalization of alkynes.

In this review, direct cyanation, hydrocyanation, dicyanation, cyanofunctionalization and other cyanation reactions of alkynes were highlighted. Firstly, the use of nitriles and development of cyanation was simply introduced. After presenting the natural properties of alkynes, cyanation reactions of alkynes were classified and introduced in detail.

Bimetallic and postsynthetically alloyed PtCu nanostructures with tunable reactivity for the methanol oxidation reaction.

Designing effective catalysts by controlling morphology and structure is key to improving the energy efficiency of fuel cells. A good understanding of the effects of specific structures on electrocatalytic activity, selectivity, and stability is needed. Here, we propose a facile method to synthesize PtCu bimetallic nanostructures with controllable compositions by using Cu nanowires as a template and ascorbic acid as a reductant.

Target-activated transcription for the amplified sensing of protease biomarkers.

Signal amplification is an effective way to achieve sensitive analysis of biomarkers, exhibiting great promise in biomedical research and clinical diagnosis. Inspired by the transcription process, here we present a versatile strategy that enables effective amplification of proteolysis into nucleic acid signal outputs in a homogeneous system. In this strategy, a protease-activatable T7 RNA polymerase is engineered as the signal amplifier and achieves 3 orders of magnitude amplification in signal gain.

Three-dimensional microspheric g-CN coupled by biochar: facile sodium alginate immobilization and excellent photocatalytic Cr(iv) reduction.

Photocatalysts comprising biochar and g-CN loaded on sodium alginate were prepared and characterized in terms of reusability and photocatalytic Cr(vi) reduction performance. The observed photocurrent responses as well as photoluminescence and UV-visible diffuse reflectance spectra showed that the best-performing catalyst featured the benefits of efficient photogenerated charge separation, superior electron conductance/transfer, and excellent light adsorption ability, which resulted in a higher photocatalytic Cr(vi) reduction performance compared to that of pure g-CN powder. The prepared composite was shown to be reusable and well separable from the reaction mixture, thus being a promising material for the practical photocatalytic removal of Cr(vi) from wastewater.

DNAzyme-Mediated Genetically Encoded Sensors for Ratiometric Imaging of Metal Ions in Living Cells.

Genetically encoded fluorescent proteins (FPs) have been used for metal ion detection. However, their applications are restricted to a limited number of metal ions owing to the lack of available metal-binding proteins or peptides that can be fused to FPs and the difficulty in transforming the binding of metal ions into a change of fluorescent signal. We report herein the use of Mg-specific 10-23 or Zn-specific 8-17 RNA-cleaving DNAzymes to regulate the expression of FPs as a new class of ratiometric fluorescent sensors for metal ions.

Femtosecond laser-induced non-thermal welding for a single Cu nanowire glucose sensor.

Copper nanowires (CuNWs) are a key building block to facilitate carrier conduction across a broad range of nanodevices. For integration into nanoscale devices, manipulation and welding of these nanowires need to be overcome. Based on high energy density laser processing investigation, we report on innovative welding of single CuNWs to a silver film using a tightly focused laser beam combined with manipulation of CuNWs through the dielectrophoresis (DEP) method.

Metal-free oxidative trifluoromethylation of indoles with CFSONa on the C2 position.

An efficient method of synthesizing 2-trifluoromethylindoles from indoles with easy-to-handle, cheap and low-toxic CFSONa under metal-free conditions is described, which selectively introduces trifluoromethyl to indoles on the C2 position. The desired product can be obtained in 0.7 g yield.

An ESIPT-Based Ratiometric Fluorescent Probe for Highly Sensitive and Rapid Detection of Sulfite in Living Cells.

The novel ratiometric fluorescent probe HPQRB with an ESIPT effect based on Michael addition for highly sensitive and fast detection of sulfite in living HepG2 cells is reported. HPQRB can be easily synthesized by a two-step condensation reaction. HPQRB has a large emission shift (Δ=116 nm), which is beneficial for fluorescence imaging research, and its sulfite-responsive site is based on a rhodamine-like structure with the emission peak at 566 nm, which decreases with increasing sulfite concentration.

Adsorption mechanism of polyethyleneimine modified magnetic core-shell FeO@SiO nanoparticles for anionic dye removal.

In this paper, polyethyleneimine modified magnetic core-shell FeO@SiO nanoparticles (FeO@SiO/PEI) were innovatively synthesized and investigated using various techniques such as TEM, TGA, FT-IR, XRD, VSM and XPS. The adsorption performance based on the removal of the anionic dyes Methyl orange and Congo red from aqueous solution was studied systematically. The results showed that the adsorption rate of anionic dyes MO and CR increased rapidly then decreased gradually as the pH increased, the adsorption capacity of FeO@SiO/PEI for MO was better than that for CR, and the maximum adsorption capacity for MO and CR was 231.

The Effects of Interaction between Climate Change and Land-Use/Cover Change on Biodiversity-Related Ecosystem Services.

Climate change and land-use/cover change (LUCC) are two major types of global environmental change. They are increasingly challenging the main objectives of ecosystem management, which are to provide ecosystem services sustainably to society and maintain biodiversity. However, a comprehensive understanding of how climate-land-use change affects these primary goals of ecosystem management is still lacking.

Nature of Bimetallic Oxide SbMoO/rGO Anode for High-Performance Potassium-Ion Batteries.

Potassium-ion batteries (KIBs) are one of the most appealing alternatives to lithium-ion batteries, particularly attractive in large-scale energy storage devices considering the more sufficient and lower cost supply of potassium resources in comparison with lithium. To achieve more competitive KIBs, it is necessary to search for anode materials with a high performance. Herein, the bimetallic oxide SbMoO, with the presence of reduced graphene oxide, is reported as a high-performance anode material for KIBs in this study, achieving discharge capacities as high as 402 mAh g at 100 mA g and 381 mAh g at 200 mA g, and reserving a capacity of 247 mAh g after 100 cycles at a current density of 500 mA g.

Facile synthesis of shell-derived hard carbon as an anode material for lithium-ion batteries.

A comparatively facile and ecofriendly process has been developed to synthesize porous carbon materials from shells. Potassium carbonate solution (KCO) impregnation is introduced to modify the functional groups on the surface of shells, which may play a role in promoting the development of pore structure during carbonization treatment. Moreover, a small amount of naturally embedded nitrogen and sulfur in the shells can also bring about the formation of pores.

Development of different deep eutectic solvent aqueous biphasic systems for the separation of proteins.

In this work, aqueous biphasic systems (ABSs) formed by different deep eutectic solvents (DESs) were prepared and applied to extract proteins. The five kinds of DESs comprised amino acids and polyols ([amino acids][polyols]). They were combined with another DES resulting from tetrabutylammonium chloride and polypropylene glycol 400 ([TBAC][PPG400]) to form ABSs.

Preparation of mesoporous ZnAlO nanoflakes by ion exchange from a Na-dawsonite parent material in the presence of an ionic liquid.

Herein, mesoporous ZnAlO spinel nanoflakes were prepared by an ion-exchange method from a Na-dawsonite parent material in the presence of an ionic liquid, 1-butyl-2,3-dimethylimidazolium chloride ([bdmim][Cl]), followed by calcination at 700 °C for 2 h. The as-obtained products were characterized by several techniques such as X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDX). The ZnAlO nanoflakes with the thickness of ∼20 nm were composed of numerous nanoparticles, which resulted in a high specific surface area of 245 m g.

Direct synthesis of 2-oxo-acetamidines from methyl ketones, aromatic amines and DMF copper-catalyzed C(sp)-H amidination.

A convenient method for the synthesis of 2-oxo-acetamidines from methyl ketones using aromatic amines and DMF as nitrogen sources is reported copper-catalyzed C(sp)-H amidination. Various methyl ketones react readily with aromatic amines and DMF, producing 2-oxo-acetamidines in yields of 47 to 92%. This protocol features the simultaneous formation of C-N and C[double bond, length as m-dash]N bonds using DMF and aromatic amines as two different nitrogen sources.