DNAzyme-Derived Aptamer Reversely Regulates the Two Types of Enzymatic Activities of Covalent-Organic Frameworks for the Colorimetric Analysis of Uranium.

Nanozymes are nanomaterials with enzyme-mimetic activity. It is known that DNA can interact with various nanozymes in different ways, enhancing or inhibiting the activity of nanozymes, which can be used to develop various biosensors. In this work, we synthesized a photosensitive covalent-organic framework (Tph-BT) as a nanozyme, and its oxidase and peroxidase activities could be reversely regulated by surface modification of single-stranded DNA (ssDNA) for the colorimetric detection of UO22+. Tph-BT exhibits excellent oxidase activity and weak peroxidase activity, and it is surprising to find that the UO22+-specific DNA aptamer can significantly inhibit the oxidase activity while greatly enhancing the peroxidase activity. The present UO22+ interacts with the DNA aptamer to form secondary structures and detaches from the surface of Tph-BT, thereby restoring the enzymatic activity of Tph-BT. Based on the reversed regulation effects of the DNA aptamer on the two types of enzymatic activities of Tph-BT, a novel "off-on" and "on-off" sensing platform can be constructed for the colorimetric analysis of UO22+. This research demonstrates that ssDNA can effectively regulate the different types of enzymatic activities of single COFs and achieve the sensitive and selective colorimetric analysis of radionuclides by the naked eye.

Reversed Regulation Effects of ssDNA on the Mimetic Oxidase and Peroxidase Activities of Covalent Organic Frameworks.

Nanomaterials with enzyme mimetic activity have attracted extensive attention, especially in the regulation of their catalytic activities by biomolecules or other polymers. Here, a covalent organic framework (Tph-BT COF) with excellent photocatalytic activity is constructed by Schiff base reaction, and its mimetic oxidase activity and peroxidase activity is inversely regulated via single-stranded DNA (ssDNA). Under light-emitting diode (LED) light irradiation, Tph-BT exhibited outstanding oxidase activity, which efficiently catalyzed oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) to produce blue oxTMB, and ssDNA, especially those with poly-thymidine (T) sequences, can significantly inhibit its oxidase activity. On the contrary, Tph-BT showed weak peroxidase activity, and the presence of ssDNA, particularly poly-cytosine (C) sequences, can remarkably enhance the peroxidase activity. The influence of base type, base length, and other factors on the activities of two enzymes is also studied, and the results reveal that the adsorption of ssDNA on the surface of Tph-BT prevented intersystem crossing (ISC) and energy transfer processes to reduce 1 O2 generation, while the electrostatic interaction between ssDNA and TMB enhanced Tph-BT's affinity for TMB to facilitate the electron transfer from TMB to • OH. This study investigates multitype mimetic enzyme activities of nonmetallic D-A conjugated COFs and demonstrates their feasibility of regulation by ssDNA.

Semiconductor-Metal Phase Transition and Emergent Charge Density Waves in 1T-ZrX2 (X = Se, Te) at the Two-Dimensional Limit.

A charge density wave (CDW) is a collective quantum phenomenon in metals and features a wavelike modulation of the conduction electron density. A microscopic understanding and experimental control of this many-body electronic state in atomically thin materials remain hot topics in materials physics. By means of material engineering, we realized a dimensionality and Zr intercalation induced semiconductor-metal phase transition in 1T-ZrX2 (X = Se, Te) ultrathin films, accompanied by a commensurate 2 × 2 CDW order. Furthermore, we observed a CDW energy gap of up to 22 meV around the Fermi level. Fourier-transformed scanning tunneling microscopy and angle-resolved photoemission spectroscopy reveal that 1T-ZrX2 films exhibit the simplest Fermi surface among the known CDW materials in TMDCs, consisting only of a Zr 4d derived elliptical electron conduction band at the corners of the Brillouin zone.

Binding-Induced Fibrillogenesis Peptides Recognize and Block Intracellular Vimentin Skeletonization against Breast Cancer.

Life is recognized as a sophisticated self-assembling material system. Cancer involves the overexpression and improper self-assembly of proteins, such as cytoskeleton protein vimentin, an emerging target related to tumor metastasis. Herein, we design a binding-induced fibrillogenesis (BIF) peptide that in situ forms fibrous networks, blocking the improper self-assembly of vimentin against cancer. The BIF peptide can bind to vimentin and subsequently perform fibrillogenesis to form fibers on vimentin. The resultant peptide fibrous network blocks vimentin skeletonization and inhibits the migration and invasion of tumor cells. In mouse models of tumor metastasis, the volume of tumor and the number of lung metastases are markedly decreased. Moreover, the efficacy of BIF peptide (5 mg/kg) is much higher than small molecular antimetastasis drug withaferin A (5 mg/kg) as a standard, indicating that the BIF peptide shows advantages over small molecular inhibitors in blocking the intracellular protein self-assembly.

Direct Observation of Full-Gap Superconductivity and Pseudogap in Two-Dimensional Fullerides.

Alkali-fulleride superconductors with a maximum critical temperature T_{c}∼40 K exhibit a similar electronic phase diagram to that of unconventional high-T_{c} superconductors. Here we employ cryogenic scanning tunneling microscopy to show that trilayer K_{3}C_{60} displays fully gapped strong coupling s-wave superconductivity, accompanied by a pseudogap above T_{c}∼22 K and within vortices. A precise control of the electronic correlations and potassium doping enables us to reveal that superconductivity occurs near a superconductor-Mott-insulator transition and reaches maximum at half-filling. The s-wave symmetry retains over the entire phase diagram, which, in conjunction with an abrupt decline of the superconductivity below half-filling, indicates that alkali fullerides are predominantly phonon-mediated superconductors, although the electronic correlations also come into play.

Direct Visualization of Ambipolar Mott Transition in Cuprate CuO_{2} Planes.

Identifying the essence of doped Mott insulators is one of the major outstanding problems in condensed matter physics and the key to understanding the high-temperature superconductivity in cuprates. We report real space visualization of Mott insulator-metal transition in Sr_{1-x}La_{x}CuO_{2+y} cuprate films that cover both the electron- and hole-doped regimes. Tunneling conductance measurements directly on the copper-oxide (CuO_{2}) planes reveal a systematic shift in the Fermi level, while the fundamental Mott-Hubbard band structure remains unchanged. This is further demonstrated by exploring the atomic-scale electronic response of CuO_{2} to substitutional dopants and intrinsic defects in a sister compound Sr_{0.92}Nd_{0.08}CuO_{2}. The results may be better explained in the framework of self-modulation doping, similar to that in semiconductor heterostructures, and form a basis for developing any microscopic theories for cuprate superconductivity.

The construction of a stable hydrogen-bonded organic framework for the photocatalytic reduction and removal of uranium.

An imidazolyl hydrogen-bonded organic framework (HOF-T) with outstanding thermal and water stability was constructed by C-H⋯N hydrogen bonding and C-H⋯π interactions. UO22+ can be selectively captured by the imidazole group of HOF-T and rapidly reduced to UO2 under visible light irradiation, realizing exceptional uranium removal with high capacity and fast kinetics.

Efficient capture of iodine in steam and water media by hydrogen bond-driven charge transfer complexes.

Untreated radioactive iodine (129I and 131I) released from nuclear power plants poses a significant threat to humans and the environment, so the development of materials to capture iodine from water media and steam is critical. Here, we report a charge transfer complex (TCNQ-MA CTC) with abundant nitrogen atoms and π-conjugated system for adsorption of I2 vapor and I3- from aqueous solutions. Due to the synergistic binding mechanism of benzene/triazine rings and N-containing groups with iodine, special I-π and charge transfer interaction can be formed between the guest and the host, and thus efficient removal of I2 and I3- can be realized by TCNQ-MA CTC with the adsorption capacity up to 2.42 g/g and 800 mg/g, respectively. TCNQ-MA CTC can capture 92% of I3- within 2.5 min, showing extremely fast kinetics, excellent selectivity and high affinity (Kd = 5.68 × 106 mL/g). Finally, the TCNQ-MA CTC was successfully applied in the removal of iodine from seawater with the efficiency of 93.71%. This work provides new insights in the construction of charge transfer complexes and lays the foundation for its environmental applications.

YuPingFeng (YPF) upregulates caveolin-1 (CAV1) to alleviate pulmonary fibrosis through the TGF-ß1/Smad2 pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Traditional Chinese medicine (TCM) is considered a valuable asset in China's medical tradition. YPF is a classic prescription that has been derived from the "Jiu Yuan Fang" formula and consists of three herbs: Huangqi (Astragalus membranaceus Bunge), Baizhu (Atractylodes rubra Dekker), and Fangfeng (Saposhnikovia divaricata (Turcz.) Schischk). This prescription is widely acclaimed for its exceptional pharmacological properties, including potent antioxidant effects, hormone regulation, and immune modulation effects. AIM OF THE STUDY: Previous research provides evidence suggesting that YPF may have therapeutic effects on pulmonary fibrosis. Further exploration is essential to confirm its effectiveness and elucidate the fundamental processes. MATERIALS AND METHODS: First, the active components and target genes of YPF were extracted from the Traditional Chinese Medicine Systems Pharmacology (TCMSP) database. Next, the GSE53845 dataset, which contains information on pulmonary fibrosis, was downloaded from the GEO database. Network informatics methods was then be utilized to identify target genes associated with pulmonary fibrosis. A YPF-based network of protein-protein interactions was constructed to pinpoint possible target genes for pulmonary fibrosis treatment. Additionally, an in vitro model of pulmonary fibrosis induced by bleomycin (BLM) was established to further investigate and validate the possible mechanisms underlying the effectiveness of YPF. RESULTS: In this study, a total of 24 active ingredients of YPF, along with 178 target genes associated with the treatment, were identified. Additionally, 615 target genes related to pulmonary fibrosis were identified. Functional enrichment analysis revealed that 18 candidate genes (CGs) exhibited significant responses to tumor necrosis factor, NF-kB survival signaling, and positive regulation of apoptosis processes. Among these CGs, CAV1, VCAM1, and TP63 were identified as key target genes. Furthermore, cell experiments confirmed that the expression of CAV1 protein and RNA expression was increased in pulmonary fibrosis, but significantly decreased after treatment with YPF. Additionally, the expression of pSmad2, α-SMA, TGF-ß1, and TNF-α was also decreased following YPF treatment. CONCLUSIONS: Network pharmacology analysis revealed that YPF exhibits significant potential as a therapeutic intervention for pulmonary fibrosis by targeting various compounds and pathways. This study emphasizes that the efficacy of YPF in treating pulmonary fibrosis may be attributed to its ability to up-regulate CAV1 expression and inhibiting pulmonary fibrosis via modulation of the TGF-ß1/Smad2 signaling pathway. These findings underscore the promising role of YPF and its ability to potentially alleviate pulmonary fibrosis.

Anemia and risk of periprocedural cerebral injury detected by diffusion-weighted magnetic resonance imaging in patients undergoing transcatheter aortic valve replacement.

BACKGROUND: Anemia is prevalent in patients undergoing transcatheter aortic valve replacement (TAVR) and has been linked to impaired outcomes after the procedure. Few studies have evaluated the impact of anemia and new ischemic lesions post TAVR. METHODS: We prospectively enrolled 158 patients who received TAVR in our center. Anemia was defined according to the World Health Organization criteria as hemoglobin <12 g/dL in women and <13 g/dL in men. All patients underwent diffusion-weighted magnetic resonance imaging (DW-MRI) procedure before and within 4-7 days after TAVR. RESULTS: Anemia was present in 85 (53.8%) patients who underwent TAVR, and 126 (79.7%) patients had 718 new DW-MRI positive lesions with a mean of 4.54±5.26 lesions per patient. The incidence of new ischemic lesions was 81.2% in patients with anemia versus 78.1% in patients without anemia (P=0.629). Moreover, anemic patients had bigger total volume/lesions in the anterior cerebral artery/middle cerebral artery (ACA/MCA) and MCA regions compared to the non-anemic patients (31.89±55.78 mm3 vs. 17.08±37.39 mm3, P=0.049; and 54.54±74.72 mm3 vs. 33.75±46.03 mm3, P=0.034). Anemia was independently associated with the volume/lesion in the ACA/MCA (ß=16.796, 95% confidence interval [95% CI] 2.001 to 31.591, P=0.026) and in the MCA zone (ß=0.020, 95% CI 0.001 to 0.040, P=0.041). CONCLUSIONS: Patients with pre-procedural anemia may have bigger total volume/lesions in the ACA/MCA and MCA regions compared to the non-anemic patients. Whether the consequences of bigger total volume/lesions impact neurological and cognitive outcomes remains to be investigated.

Direct observation of nodeless superconductivity and phonon modes in electron-doped copper oxide Sr1-xNdxCuO2.

The microscopic understanding of high-temperature superconductivity in cuprates has been hindered by the apparent complexity of crystal structures in these materials. We used scanning tunneling microscopy and spectroscopy to study the electron-doped copper oxide compound Sr1- x Nd x CuO2, which has only bare cations separating the CuO2 planes and thus the simplest infinite-layer structure of all cuprate superconductors. Tunneling conductance spectra of the major CuO2 planes in the superconducting state revealed direct evidence for a nodeless pairing gap, regardless of variation of its magnitude with the local doping of trivalent neodymium. Furthermore, three distinct bosonic modes are observed as multiple peak-dip-hump features outside the superconducting gaps and their respective energies depend little on the spatially varying gaps. As well as the bosonic modes, with energies identical to those of the external, bending and stretching phonons of copper oxides, our findings reveal the origin of the bosonic modes in lattice vibrations rather than spin excitations.

An antibody-like peptidic network for anti-angiogenesis.

Different from chemical (small molecular inhibitor) and biological (monoclonal antibody) drugs, herein, based on angiogenesis-related neuropilin-1 (NRP-1), we develop a biomimetic superstructure drug, i.e. an antibody-like peptidic network (ALPN) to achieve the high-efficient treatment of choroidal neovascularization (CNV). The ALPN in nanoparticulated formulation (ALPN-NPS) can bind NRP-1 through targeting unit and form fibrous peptidic networks trapping NRP-1 on the surface of endothelial cells (ECs), leading to anti-angiogenesis. The ALPN shows high-efficacy against angiogenesis in CNV rat model ascribed to the superstructure-enhanced binding and blockage of NRP-1. The very low dose of ALPN (0.263 µg/Kg) exhibits similar anti-angiogenesis effect comparing with monoclonal antibody bevacizumab (23.5 µg/Kg), which shows potential advantages over traditional monoclonal antibodies.

A biomimetic peptide recognizes and traps bacteria in vivo as human defensin-6.

Using broad-spectrum antibiotics for microbial infection may cause flora disequilibrium, drug-resistance, etc., seriously threatening human health. Here, we design a human defensin-6 mimic peptide (HDMP) that inhibits bacterial invasion in vivo through mimicking the mechanisms of human defensin-6 with high efficiency and precision. The HDMP with ligand and self-assembling peptide sequence recognizes bacteria through ligand-receptor interactions and subsequently traps bacteria by an in situ adaptive self-assembly process and resulting nanofibrous networks; these trapped bacteria are unable to invade host cells. In four animal infection models, the infection rate was markedly decreased. Notably, administration of HDMP (5 mg/kg) nanoparticles increased the survival rate of mice with methicillin-resistant S. aureus bacteremia by as much as 100%, even more than that of vancomycin treatment (5 mg/kg, 83.3%)-treated group, the golden standard of antibiotics. This biomimetic peptide shows great potential as a precise and highly efficient antimicrobial agent.

MOF-Templated Synthesis of Co3O4@TiO2 Hollow Dodecahedrons for High-Storage-Density Lithium-Ion Batteries.

Co3O4 nanostructures have been extensively studied as anode materials for rechargeable lithium-ion batteries (LIBs) because of their stability and high energy density. However, several drawbacks including low electrical transport and severe volume changes over a long period of operation have limited their utilities in LIBs. Rational composite design is becoming an attractive strategy to improve the performance and stability of potential lithium-ion-battery anode materials. Here, a simple method for synthesizing hollow Co3O4@TiO2 nanostructures using metal-organic frameworks as sacrificial templates is reported. Being used as an anode material for LIBs, the resulting composite exhibits remarkable cycling performance (1057 mAh g-1 at 100 mA g-1 after 100 cycles) and good rate performance. The optimized amorphous Co3O4@TiO2 hollow dodecahedron shows a significant improvement in electrochemical performance and shows a wide prospect as an advanced anode material for LIBs in the future.

Ascending aortic dilatation rate after transcatheter aortic valve replacement in patients with bicuspid and tricuspid aortic stenosis: A multidetector computed tomography follow-up study.

BACKGROUND: Current data is lacking about the progression of ascending aortic dilatation after transcatheter aortic valve replacement (TAVR) in aortic stenosis (AS) patients with bicuspid aortic valve (BAV) and tricuspid aortic valve (TAV). This study aims to assess the ascending aortic dilatation rate (mm/year) after TAVR in patients with BAV versus TAV using a multidetector computed tomography (MDCT) follow-up and to determine the predictors of ascending aortic dilatation rate. METHODS: Severe AS patients undergoing TAVR from March 2013 to March 2018 at our center with MDCT follow-ups were included. BAV and TAV were identified using baseline MDCT. Baseline and follow-up MDCT images were analyzed, and the diameters of ascending aorta were measured. Study end point is ascending aortic dilatation rate (mm/year). Furthermore, factors predicting ascending aortic dilatation rate were also investigated. RESULTS: Two hundred and eight patients were included, comprised of 86 BAV and 122 TAV patients. Five, 4, 3, 2, and 1-year MDCT follow-ups were achieved in 7, 9, 30, 46, and 116 patients. The ascending aortic diameter was significantly increased after TAVR in both BAV group (43.7±4.4 mm vs. 44.0±4.5 mm; P<0.001) and TAV group (39.1±4.8 mm vs. 39.7±5.1 mm; P<0.001). However, no difference of ascending aortic dilatation rate was found between BAV and TAV group (0.2±0.8 mm/year vs. 0.3±0.8 mm/year, P=0.592). Multivariate linear regression revealed paravalvular leakage (PVL) grade was independently associated with ascending aortic dilatation rate in the whole population and BAV group, but not TAV group. No aortic events occurred during follow-ups. CONCLUSION: Ascending aortic size continues to grow after TAVR in BAV patients, but the dilatation rate is mild and comparable to that of TAV patients. PVL grade is associated with ascending aortic dilatation rate in BAV patients post-TAVR.

[Extracellular polymeric substances (EPS) of white-rot fungus and their effects on Pb2+ adsorption by biomass].

The extracellular polymeric substances (EPS) of P. chrysosporium and their effects on Pb2+ biosorption were studied. The product, composition of EPS and the effects on Pb2+ biosorption capacity were investigated in lab via flask experiments. The surface changes of mycelium before and after EPS extraction, before and after Pb2+ adsorption were researched by environment scanning electron microscope with energy-dispersive X-ray analysis (ESEM-EDX). Results showed that at 113 h, the maximum yield of EPS was 125.5 mg/L, which contained 46.6% - 54.3% of sugar and 31.2% - 35.1% of protein. The results of control test after EPS extraction displayed a decrease of biosorption capacity of Pb2+ among 2.12 mg/g (113 h) - 7.73 mg/g (41 h). The results of environment scanning electron microscope (ESEM) showed that the EPS extraction affected the cell wall of white-rot fungus and the Pb-contained globular particle after Pb2+ uptake, which was very useful for further study on heavy metal biosorption mechanism.

Coarsening of extracellularly biosynthesized cadmium crystal particles induced by thioacetamide in solution.

A novel coarsening route for extracellularly biosynthesized cadmium nanocrystals was investigated for the first time. In this process, the white rot fungus Coriolus versicolor was employed to take up cadmium ions and synthesize extracellular cadmium crystal particles. The coarsening of the particles was induced by thioacetamide under certain conditions. Scanning electron microscopy showed that the formed cadmium crystal particles were coarsened from about 100nm to 2-3µm. The corresponding energy-dispersive X-ray spectra confirmed the presence of proteins in the particles. The maximum removal efficiency of Cd(II) increased from 17% to 87%, and the corresponding sorption capacity of biomass increased from 4 to 24mgg(-1) with the completion of the coarsening process. The properties of the coarsened particles were also examined using X-ray diffraction (XRD) and transmission electron microscopy (TEM). XRD analysis of fungal mycelial pellets embedded with the coarsened particles confirmed the formation of cubic crystalline cadmium sulfide particles. The TEM results suggest that the coarsened particles were composed of clusters of several smaller particles. The changes in the functional groups on the biomass surface were studied through Fourier transform infrared spectroscopy. Based on the results above, a possible mechanism for the formation and coarsening of cadmium crystal particle is also discussed.