Electron-Donating/Accepting Group Modulation Enhanced Fluorescent Sensing of Synthetic Cannabinoid JWH-018 via Through-Space Charge Transfer.

The substituent design and photophysical property manipulation are of paramount importance in fluorescent probe design, particularly crucial for chemically inactive molecules that lack reactive functional groups, such as synthetic cannabinoids. Here, a ratiometric fluorescent probe, 2-(5-phenyl-8-(4-(trifluoromethyl)phenyl)pyrimido[4,5-]pyridazin-2-yl)phenol (DPTF), was selected and synthesized using trifluoromethyl as an electron acceptor for the sensitive and specific detection of one representative synthetic cannabinoid, JWH-018 (1-naphthyl(1-pentyl-1H-indol-3-yl)methanone). The DPTF probe, driven by intermolecular through-space charge transfer (TSCT), exhibits a theoretically calculated limit of detection (LOD) of 2.

Exactly Matching the FRET Energy of the Functionalized Upconversion Nanoprobe to Boost the Sensing Performance toward Perchlorate.

The design and development of ultra-accurate probe is of great significance, but there is still a big challenge for chemical sensing in complex practical detection scenes. Here, a unique optical nanoprobe with high sensitivity and anti-interference capability toward perchlorate is designed by exactly matching the FRET energy of the functionalized ligand with the green emission of the UCNPs. Benefiting from the design of specific recognition sites and the intrinsic superiority of the FRET mechanism, the nanoprobe demonstrates an ultralow detection limit of 1.

Acquisition of object and temperature series in medium resolution off-axis electron holography with live drift correction.

Collecting and averaging large datasets is a common practice in transmission electron microscopy to improve the signal-to-noise ratio. Averaging data in off-axis electron holography requires automated tools capable of correcting both the drift of the interference fringes and the drift of the specimen. This can be achieved either off-line, by post-processing hologram series, or on-line, through real-time microscope control.

Driving DNA Nanopore Membrane Insertion through Dipolar Coupling.

DNA nanopores appear to be a plausible alternative to the use of transmembrane proteins. The specificity and programmability of DNA interactions allow the design of synthetic channels that insert into lipid bilayers and can regulate the ionic transport across them. In this Communication, we investigate the dependence of insertion capabilities on the electrostatic properties of the nanopore and show that the presence of a permanent electric dipole is an important factor for the nanopore to insert into the membrane.

Embedded Skyrmion Bags in Thin Films of Chiral Magnets.

Magnetic skyrmions are topologically nontrivial spin configurations that possess particle-like properties. Earlier research has mainly focused on a specific type of skyrmion with topological charge Q = -1. However, theoretical analyses of 2D chiral magnets have predicted the existence of skyrmion bags-solitons with arbitrary positive or negative topological charge.

Negative mixing enthalpy solid solutions deliver high strength and ductility.

Body-centred cubic refractory multi-principal element alloys (MPEAs), with several refractory metal elements as constituents and featuring a yield strength greater than one gigapascal, are promising materials to meet the demands of aggressive structural applications. Their low-to-no tensile ductility at room temperature, however, limits their processability and scaled-up application. Here we present a HfNbTiVAl alloy that shows remarkable tensile ductility (roughly 20%) and ultrahigh yield strength (roughly 1,390 megapascals).

Hopfion rings in a cubic chiral magnet.

Magnetic skyrmions and hopfions are topological solitons-well-localized field configurations that have gained considerable attention over the past decade owing to their unique particle-like properties, which make them promising objects for spintronic applications. Skyrmions are two-dimensional solitons resembling vortex-like string structures that can penetrate an entire sample. Hopfions are three-dimensional solitons confined within a magnetic sample volume and can be considered as closed twisted skyrmion strings that take the shape of a ring in the simplest case.

Selection of Aptamer for N-Methyl Mesoporphyrin IX to Develop Porphyrin Metalation DNAzyme.

Mesoporphyrin IX (MPIX) contains a planar macrocycle center that can interact with various divalent metal ions through the exposed binding sites, leading to the metalation of MPIX. The DNA aptamers for porphyrin molecules usually display different catalytic functions (termed deoxyribozymes or DNAzymes), which can accelerate such chemical reactions. Inspired by this, an affinity chromatography selection approach was designed for identifying a porphyrin metalation DNAzyme.

Atomic-Scale Insights into Nickel Exsolution on LaNiO Catalysts via Electron Microscopy.

Using a combination of bulk and surface characterization techniques, we provide atomic-scale insight into the complex surface and bulk dynamics of a LaNiO perovskite material during heating . Driven by the outstanding activity LaNiO in the methane dry reforming reaction (DRM), attributable to the decomposition of LaNiO during DRM operation into a Ni//LaO composite, we reveal the Ni exsolution dynamics both on a local and global scale by electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. To reduce the complexity and disentangle thermal from self-activation and reaction-induced effects, we embarked on a heating experiment in vacuo under comparable experimental conditions in all methods.

Detection of Short DNA Sequences with DNA Nanopores.

Several studies suggest strong correlation between different types of cancer and the relative concentration of short circulating RNA sequences (miRNA). Because of short length and low concentration, miRNA detection is not easy. Standard methods such as RT-PCR require both the standard PCR amplification step and a preliminary additional step of reverse transcription.

Investigation and improvement of catalytic activity of G-quadruplex/hemin DNAzymes using designed terminal G-tetrads with deoxyadenosine caps.

It is generally acknowledged that G-quadruplexes (G4s) acquire peroxidase activity upon interaction with hemin. Hemin has been demonstrated to bind selectively to the 3'-terminal G-tetrad of parallel G4s end-stacking; however, the relationships between different terminal G-tetrads and the catalytic functions of G4/hemin DNAzymes are not fully understood. Herein, the oligonucleotide d(AGGGGA) and its three analogues, d(AGGGGA), d(AGGGGA) and d(AGGGGA) (G indicates 8-bromo-2'-deoxyguanosine), were designed.

Ni-Nitrilotriacetic Acid Affinity SELEX Method for Selection of DNA Aptamers Specific to the N-Cadherin Protein.

Nucleic acid aptamers are single-stranded oligonucleotides that may be evolved for affinity and specificity for their targets and can be easily produced, regenerated, and stabilized. In this study, we adapted Ni-NTA (nickle-charged nitrilotriacetic acid) affinity-chromatography in the development of single-stranded DNA aptamers against N-cadherin protein by systematic evolution of ligands by exponential enrichment (SELEX). After ten rounds of selection, two aptamers, designated NS13 and NC23, were selected, which showed low dissociation constants of 93 and 174 nM, respectively.

Ligand Selectivity by Inserting GCGC-Tetrads into G-Quadruplex Structures.

G-Quadruplexes (G4s) assembled from tandem G-rich repeat sequences exhibit significant biological functions and applications, which may well depend on their structural features, such as the planar arrangement of G-tetrads and flexibility of loop regions. It has been found that cytosine-intercalated G-repeat sequences also assemble to be quadruplex structures, involving the formation of nonplanar GCGC-tetrads. Herein, to investigate the effect of GCGC-tetrads on structural properties of G4s, some previously studied quadruplexes with or without GCGC-tetrads were selected, and were used to interact with various developed G4 ligands.

In Vitro Selection of DNA Aptamers for a Small-Molecule Porphyrin by Gold Nanoparticle-Based SELEX.

In this study, a new strategy for the selection of aptamers against small-molecule target was established using gold nanoparticles (AuNPs) as the separation matrix and Zinc(II)-Protoporphyrin IX (ZnPPIX) as the target molecule without the immobilization step due to the absorption of ssDNA on AuNPs. The progress of the selection process was monitored by the recovery rate and the fluorescence enhancement of N-methyl mesoporphyrin IX (NMM) after reacting with each selected pool. After 11 rounds of selection, a truncated aptamer ZnP1.

Construction of One- and Two-Dimensional Nanostructures by the Sequential Assembly of Quadruplex DNA Scaffolds.

A quadruplex-integrated assembly method is proposed for the organization and regulation of various nanoscale architectures. In this method, two types of one-dimensional DNA nanostructures formed by two well-designed GC-rich single strands assemble into two-dimensional (2D) DNA nanostructures based on the self-assembly of dimeric G-quadruplex and I-motif structures. Subsequently, a C-rich strand and two biotin-modified G-rich strands primordially form a notched double helix in LiCl solution (pH 8).

Exploration of Catalytic Nucleic Acids on Porphyrin Metalation and Peroxidase Activity by in Vitro Selection of Aptamers for N-Methyl Mesoporphyrin IX.

To develop a novel light-up probe and DNAzyme, we selected aptamers for N-methyl mesoporphyrin IX (NMM), a common fluorogenic analogue of coenzyme hemin, by a modified affinity chromatography-based systematic evolution of ligands by exponential enrichment (SELEX). Two truncated aptamers Nm1 and Nm2 with low micromolar dissociation constants (0.75 and 13.