Organic-inorganic covalent-ionic molecules for elastic ceramic plastic.

Although organic-inorganic hybrid materials have played indispensable roles as mechanical1-4, optical5,6, electronic7,8 and biomedical materials9-11, isolated organic-inorganic hybrid molecules (at present limited to covalent compounds12,13) are seldom used to prepare hybrid materials, owing to the distinct behaviours of organic covalent bonds14 and inorganic ionic bonds15 in molecular construction. Here we integrate typical covalent and ionic bonds within one molecule to create an organic-inorganic hybrid molecule, which can be used for bottom-up syntheses of hybrid materials. A combination of the organic covalent thioctic acid (TA) and the inorganic ionic calcium carbonate oligomer (CCO) through an acid-base reaction provides a TA-CCO hybrid molecule with the representative molecular formula TA2Ca(CaCO3)2. Its dual reactivity involving copolymerization of the organic TA segment and inorganic CCO segment generates the respective covalent and ionic networks. The two networks are interconnected through TA-CCO complexes to form a covalent-ionic bicontinuous structure within the resulting hybrid material, poly(TA-CCO), which unifies paradoxical mechanical properties. The reversible binding of Ca2+-CO32- bonds in the ionic network and S-S bonds in the covalent network ensures material reprocessability with plastic-like mouldability while preserving thermal stability. The coexistence of ceramic-like, rubber-like and plastic-like behaviours within poly(TA-CCO) goes beyond current classifications of materials to generate an 'elastic ceramic plastic'. The bottom-up creation of organic-inorganic hybrid molecules provides a feasible pathway for the molecular engineering of hybrid materials, thereby supplementing the classical methodology used for the manufacture of organic-inorganic hybrid materials.

Construction and external validation of a nomogram model for predicting the risk of esophageal stricture after endoscopic submucosal dissection: a multicenter case-control study.

Esophageal stricture is a common complication after endoscopic submucosal dissection (ESD) for superficial esophageal cancer and precancerous lesions, we intend to investigate the independent risk factors of esophageal stricture after ESD by adding the data of included living habits, established a nomogram model to predict the risk of esophageal stricture, and verified it by external data. The clinical data and living habits of patients with early esophageal cancer and precancerous lesions who underwent ESD in the Affiliated Hospital of North Sichuan Medical College and Langzhong People's Hospital from March 2017 to August 2021 were retrospectively collected. The data collected from the two hospitals were used as the development group (n = 256) and the validation group (n = 105), respectively. Univariate and multivariate logistic regression analyses were used to determine independent risk factors for esophageal stricture after ESD and establish a nomogram model for the development group. The prediction performance of the nomogram model is internally and externally verified by calculating C-Index and plotting the receiver operating characteristic curve (ROC) and calibration curve, respectively. The results showed that Age, drinking water temperature, neutrophil-lymphocyte ratio, the extent of esophageal mucosal defect, longitudinal diameter of resected mucosa, and depth of tissue invasion (P < 0.05) were independent risk factors for esophageal stricture after ESD. The C-Index of the development group and validation group was 0.925 and 0.861, respectively. The ROC curve and area under the curve (AUC) of the two groups suggested that the discrimination and prediction performance of the model were good. The two groups of calibration curves are consistent and almost overlap with the ideal calibration curve, indicating that the predicted results of this model are in good agreement with the actual observed results. In conclusion, this nomogram model has a high accuracy for predicting the risk of esophageal stricture after ESD, providing a theoretical basis for reducing or avoiding esophageal stricture and guiding clinical practice.

A sensitive fluorescence detection strategy for H2O2 and glucose by using aminated Fe-Ni bimetallic MOF as fluorescent nanozyme.

An aminated Fe-Ni bimetallic metal-organic framework (Fe3Ni-MOF-NH2) with both peroxidase-like activity and fluorescence properties was developed. Fe3Ni-MOF-NH2 possessed the enhanced peroxidase-like activity through the enhanced electron transfer process and hydroxyl radical (·OH) generation. It was found that the amino group endowed the material with fluorescent property and the metal site Ni in Fe3Ni-MOF-NH2 could also enhance the fluorescence emission intensity (Ex = 345 nm, Em = 452 nm). Based on the dual excellent performance of Fe3Ni-MOF-NH2, a novel sensitive fluorescence detection strategy for H2O2 and glucose was designed and achieved. First, Fe3Ni-MOF-NH2 converted H2O2 to ·OH by exerting peroxidase-like activity, and ·OH converts catechol to o-benzoquinone. Then, the amino group in Fe3Ni-MOF-NH2 connected to o-benzoquinone, which resulted in its fluorescence quenching. The detection limit of H2O2 was as low as 5 nM. Combined with glucose oxidase which can oxidize glucose and produce H2O2 the glucose could be indirectly determined with a detection limit of 40 nM. The method was applied to the detection of low-level glucose in human urine samples with good recoveries and reproducibilities.

Strain Quantum Sensing with Spin Defects in Hexagonal Boron Nitride.

Hexagonal boron nitride is not only a promising functional material for the development of two-dimensional optoelectronic devices but also a good candidate for quantum sensing thanks to the presence of quantum emitters in the form of atom-like defects. Their exploitation in quantum technologies necessitates understanding their coherence properties as well as their sensitivity to external stimuli. In this work, we probe the strain configuration of boron vacancy centers (VB-) created by ion implantation in h-BN flakes thanks to wide-field spatially resolved optically detected magnetic resonance and submicro Raman spectroscopy. Our experiments demonstrate the ability of VB- for quantum sensing of strain and, given the omnipresence of h-BN in 2D-based devices, open the door for in situ imaging of strain under working conditions.

Excited-State Optically Detected Magnetic Resonance of Spin Defects in Hexagonal Boron Nitride.

Negatively charged boron vacancy (V_{B}^{-}) centers in hexagonal boron nitride (h-BN) are promising spin defects in a van der Waals crystal. Understanding the spin properties of the excited state (ES) is critical for realizing dynamic nuclear polarization. Here, we report zero-field splitting in the ES of D_{ES}=2160 MHz and its associated optically detected magnetic resonance (ODMR) contrast of 12% at cryogenic temperature. In contrast to nitrogen vacancy (NV^{-}) centers in diamond, the ODMR contrast of V_{B}^{-} centers is more prominent at cryotemperature than at room temperature. The ES has a g factor similar to the ground state. The ES photodynamics is further elucidated by measuring the level anticrossing of the V_{B}^{-} defects under varying external magnetic fields. Our results provide important information for utilizing the spin defects of h-BN in quantum technology.

Label-free fluorescence detection of hydrogen peroxide and glucose based on the Ni-MOF nanozyme-induced self-ligand emission.

A bifunctional Ni-MOF nanosheet was synthesized and developed for label-free fluorescent detection of H2O2 and glucose. The Ni-MOF exhibited intrinsic peroxidase-like activity and its catalytic activity was demonstrated to be originated from the hydroxyl radicals (•OH) produced in catalytic process. Since the generated •OH enabled terephthalic acid, the non-fluorescent organic ligand of Ni-MOF, to form a strongly fluorescent 2-hydroxy terephthalic acid, the Ni-MOF nanozyme was endowed with dual-function properties of mimicking peroxidase and emitting fluorescence. Based on this bifunctional Ni-MOF nanozyme, the proposed label-free fluorescence sensing strategy was applied to detecting H2O2 and glucose with wide linear ranges of 0.1-20 mM and 8-30 µM, and low detection limits of 4.0 × 10-5 M and 4.0 × 10-6 M, respectively. Furthermore, the bifunctional Ni-MOF-based label-free sensing platform was successfully used for the glucose detection in human serum samples, showing good reproducibility and high accuracy. This strategy provides a green and sensitive method for the determination of small biomolecules in practical applications by the combination of enzyme cascade reaction.

Coherent Manipulation with Resonant Excitation and Single Emitter Creation of Nitrogen Vacancy Centers in 4H Silicon Carbide.

Silicon carbide (SiC) has become a key player in the realization of scalable quantum technologies due to its ability to host optically addressable spin qubits and wafer-size samples. Here, we have demonstrated optically detected magnetic resonance (ODMR) with resonant excitation and clearly identified the ground state energy levels of the NV centers in 4H-SiC. Coherent manipulation of NV centers in SiC has been achieved with Rabi and Ramsey oscillations. Finally, we show the successful generation and characterization of single nitrogen vacancy (NV) center in SiC employing ion implantation. Our results highligh the key role of NV centers in SiC as a potential candidate for quantum information processing.

Dual-Emitting N/S-Doped Carbon Dots-Based Ratiometric Fluorescent and Light Scattering Sensor for High Precision Detection of Fe(III) Ions.

Precise and rapid sensing of Fe(III) under concerned facile conditions is important in environmental monitoring. Herein, a facile and label-free ratiometric sensor is constructed for selective determination of Fe(III) ions by coupling second-order scattering (SOS) and fluorescence. We were synthesized fluorescent N, S-doped carbon dots (N/S-CDs) via facile one-step hydrothermal treatment with an intensive fluorescence and a weak SOS signal and high quantum yield (32%). The fluorescence of N/S-CDs was quenched whereas the intensity of SOS was relatively increased by Fe(III) ions due to aggregation-induced fluorescence quenching or enhancement. Based on this effect, a novel fluorescent ratiometric probe with the combined fluorescence and SOS is proposed for the sensing of Fe(III) ions, and with the detection limit of 83 nM and linear range of 0.1-10 µM and 10-40 µM, respectively.

Two-year outcome of Trabeculo-Canalectomy for Chinese Glaucoma Patients.

To evaluate the efficacy of trabeculo-canalectomy in treating glaucoma patients, a retrospective investigation of 53 glaucoma patients (53 eyes) who underwent trabeculo-canalectomy was conducted at the First Affiliated Hospital of Nanjing Medical University, China, from April 2017 to January 2019. Intraocular pressure (IOP), visual acuity, surgical success rates, medications, and complications were monitored at post-operative 1 day, 1 week, 1, 3, 6, 12 and 24 months. Surgical success criteria were defined as 6 mm Hg≤IOP≤21 mmHg with or without additional medications. Our results showed that average IOP was statistically significant between pre-operative visit and each follow-up visit (all P <0.05). The total success rate of trabeculo-canalectomy at 1, 3, 6, 12 and 24 months was 92.5%, 86.8%, 94.3%, 92.5% and 90.6% respectively. After 3 months post-operatively, all patients had no obvious filtering blebs. The main early complications included postoperative hyphema (7.5%), elevated IOP (5.7%) and anterior chamber exudation (3.8%), which were all cured after conservative treatment. No blebitis, shallow anterior chamber, choroidal detachment and endophthalmitis were observed. Logistic regression analysis showed that patients with secondary glaucoma were more likely to undergo surgical failure 24 months post-operatively (P= 0.008). Thus, we conclude that trabeculo-canalectomy is effective and safe for the treatment of glaucoma.

Synthesis and Biological Evaluation of Amino Chalcone Derivatives as Antiproliferative Agents.

Chalcone is a common scaffold found in many biologically active compounds. The chalcone scaffold was also frequently utilized to design novel anticancer agents with potent biological efficacy. Aiming to continue the research of effective chalcone derivatives to treat cancers with potent anticancer activity, fourteen amino chalcone derivatives were designed and synthesized. The antiproliferative activity of amino chalcone derivatives was studied in vitro and 5-Fu as a control group. Some of the compounds showed moderate to good activity against three human cancer cells (MGC-803, HCT-116 and MCF-7 cells) and compound 13e displayed the best antiproliferative activity against MGC-803 cells, HCT-116 cells and MCF-7 cells with IC50 values of 1.52 µM (MGC-803), 1.83 µM (HCT-116) and 2.54 µM (MCF-7), respectively which was more potent than the positive control (5-Fu). Further mechanism studies were explored. The results of cell colony formatting assay suggested compound 10e inhibited the colony formation of MGC-803 cells. DAPI fluorescent staining and flow cytometry assay showed compound 13e induced MGC-803 cells apoptosis. Western blotting experiment indicated compound 13e induced cell apoptosis via the extrinsic/intrinsic apoptosis pathway in MGC-803 cells. Therefore, compound 13e might be a valuable lead compound as antiproliferative agents and amino chalcone derivatives worth further effort to improve amino chalcone derivatives' potency.

Organic-Inorganic Copolymerization for a Homogenous Composite without an Interphase Boundary.

Ionic oligomers and their crosslinking implies a possibility to produce novel organic-inorganic composites by copolymerization. Using organic acrylamide monomers and inorganic calcium phosphate oligomers as precursors, uniformly structured polyacrylamide (PAM)-calcium phosphate copolymer is prepared by an organic-inorganic copolymerization. In contrast to the previous PAM-based composites by mixing inorganic components into polymers, the copolymerized material has no interphase boundary owing to the homogenous incorporation of the organic and inorganic units at molecular level, resulting in a complete and continuous hybrid network. The participation of the ionic binding effect in the crosslinking process can substantially improve the mechanical strength; the copolymer can reach a modulus and hardness of 35.14±1.91 GPa and 1.34±0.09 GPa, respectively, which are far superior to any other PAM-based composites.

Optical Gating of Resonance Fluorescence from a Single Germanium Vacancy Color Center in Diamond.

Scalable quantum photonic networks require coherent excitation of quantum emitters. However, many solid-state systems can undergo a transition to a dark shelving state that inhibits the resonance fluorescence. Here, we demonstrate that by a controlled gating using a weak nonresonant laser, the resonant fluorescence can be recovered and amplified for single germanium vacancies. Employing the gated resonance excitation, we achieve optically stable resonance fluorescence of germanium vacancy centers. Our results are pivotal for the deployment of diamond color centers as reliable building blocks for scalable solid-state quantum networks.

A Novel Application of Fluorine Doped Carbon Dots Combining Vortex-Assisted Liquid-Liquid Microextraction for Determination of 4-Nitrophenol with Spectrofluorimetric Method.

A simple and fast vortex-assisted liquid-liquid microextraction (VA-LLME) combining with fluorescent carbon dots have been developed for the determination 4-nitrophenol (4-NP). The high fluorescent quantum yield (58.9%) fluorine doped carbon dots (F-CDs) were synthesized using tetrafluoroterephthalic acid as a fluorine source and using citric acid as a fluorine source and using ethylenediamine as a nitrogen source via a one-step hydrothermal method. F-CDs fluorescence was effectively quenched by 4-NP due to inner filter effect (IFE) and the strong interactions between functional groups (-COOH,-OH, -NH2 and -F groups) of the F-CDs and 4-NP. In VALLME method, n-octanol was employed as extraction solvent, and vortex-mix was exploited as a gentle mix method to reduce emulsification time and improve the extraction efficiency. The detection limits, the quantification limit and relative standard deviation for the 4-NP were found as 15 nM, 50 nM and 3.5%, respectively. Moreover, the obtained F-CDs can be employed as fluorescent probe to detect 4-NP in real environmental water samples.

Excitonic linewidth of organic quantum wires generated in reduced dimensionality matrices.

Luminescent organic quantum wires are generated in diacetylene crystalline ultra-thin films grown on orientation-inducing surfaces obtained by poly-tetrafluoroethylene (teflon) deposition. The films are characterized by atomic force microscopy showing that quasi-two-dimensional surroundings are achieved. In this particular environment, pure dephasing processes still determine the wires' homogeneous emission widths, measured using micro-photoluminescence. Coherence times that are slightly shorter in the films also exhibit a distinctive temperature dependence. A model inspired by semiconductor physics for exciton-phonon coupling accounts for the observed behaviour and evidences the role of matrix dimensionality on the coherence properties.

Active site-tuned high peroxidase-like activity nanozyme for on-the-spot detection of saliva total antioxidant capacity using smartphone devices.

Metal-Organic Framework (MOF) based nanozymes with clear structure are beneficial for exploration of structural-performance and exhibit broad prospects in improving activity. In this study, the prepared bimetallic Fe3Ni-MOF nanozyme was superior to single metal MOF in the peroxidase-like activity. Subsequently, a derivative nanozyme (Fe3Ni-MOF-Ar) was prepared by pyrolysis using Fe3Ni-MOF as the precursor in argon atomoshere with controlled temperature. The investigated of Fe3Ni-MOF-Ar revealed that the irregular macroporous state and the presence of heterovalent FeIII/FeII sites of Fe3Ni-MOF-Ar enable the retention, exposure, and electronic structure regulation of active sites, promoting the dual mechanism (the generation of •OH and electron transfer mechanism) and significantly increasing the peroxidase-like activity. Fe3Ni-MOF-Ar exhibited a strong affinity for substrate H2O2, which is higher than horseradish peroxidase. Ascorbic acid and cysteine are typical substances of antioxidants. Fe3Ni-MOF-Ar was used for sensitive colorimetric detection of ascorbic acid and cysteine, and the detection limit was as low as 150 and 60 nM. In addition, the smartphone devices was used to detection of antioxidant equivalent ascorbic acid, with a detection range of 0.5-120 µM. Fe3Ni-MOF-Ar nanozyme is feasible for sensitive detection of saliva total antioxidant capacity.

Effects of edge disorder on the stability of quantum oscillations in two-dimensional coupled systems.

This paper utilizes the theory of quantum diffusion to analyze the electron probability and spreading width of a wavepacket on each layer in a two-dimensional (2D) coupled system with edge disorder, aiming to clarify the effects of edge disorder on the stability of the electron periodic oscillations in 2D coupled systems. Using coupled 2D square lattices with edge disorder as an example, we show that, the electron probability and wavepacket spreading width exhibit periodic oscillations and damped oscillations, respectively, before and after the wavepacket reaches the boundary. Furthermore, these electron oscillations exhibit strong resistance against disorder perturbation with a longer decay time in the regime of large disorder, due to the combined influences of ordered and disordered site energies in the central and edge regions. Finally, we numerically verified the universality of the results through bilayer graphene, demonstrating that this anomalous quantum oscillatory behavior is independent of lattice geometry. Our findings are helpful in designing relevant quantum devices and understanding the influence of edge disorder on the stability of electron periodic oscillations in 2D coupled systems.

Biomimetic Self-Maturation Mineralization System for Enamel Repair.

Enamel repair is crucial for restoring tooth function and halting dental caries. However, contemporary research often overlooks the retention of organic residues within the repair layer, which hinders the growth of dense crystals and compromises the properties of the repaired enamel. During the maturation of natural enamel, the organic matrix undergoes enzymatic processing to facilitate further crystal growth, resulting in a highly mineralized tissue. Inspired by this process, a biomimetic self-maturation mineralization system is developed, comprising ribonucleic acid-stabilized amorphous calcium phosphate (RNA-ACP) and ribonuclease (RNase). The RNA-ACP induces initial mineralization in the form of epitaxial crystal growth, while the RNase present in saliva automatically triggers a biomimetic self-maturation process. The mechanistic study further indicates that RNA degradation prompts conformational rearrangement of the RNA-ACP, effectively excluding the organic matter introduced earlier. This exclusion process promotes lateral crystal growth, resulting in the generation of denser enamel-like apatite crystals that are devoid of organic residues. This strategy of eliminating organic residues from enamel crystals enhances the mechanical and physiochemical properties of the repaired enamel. The present study introduces a conceptual biomimetic mineralization strategy for effective enamel repair in clinical practice and offers potential insights into the mechanisms of biomineral formation.

Glyphosate exposure affected longevity-related pathways and reduced survival in asian honey bees (Apis cerana).

Glyphosate (N-(phosphonomethyl)glycine, GLY) ranks among the most extensively used and effective herbicides globally. However, excessive GLY utilization poses a substantial threat to the survival of honey bees (Apis cerana). Here we monitored the survival status of A. cerana treated with GLY, and conducted transcriptome sequencing of the bee gut and head to further explore potential GLY influences at the molecular level. We observed that the mortality rate of bees increased as GLY concentration escalated. Pivotal pathways emerged in response to the GLY treatment, with a substantial number of differentially expressed genes enriched in the longevity regulating pathway - multiple species. This strongly suggested that GLY may influence the physiological behavior of bees by impacting this particular pathway. Moreover, our analysis revealed a notable reduction in the enzymatic activities of CYP450 and AChE in both the bee head and intestines of when exposed to GLY. Conversely, the enzymatic activity of superoxide dismutase (SOD) in the head remained unaffected, whereas in the intestines, it exhibited a significant increase. Additionally, prophenol oxidase (PPO) and glutathione-S-transferases (GSTs) displayed contrasting trends in enzymatic activity in both organs. This study offers valuable insights into how GLY impacted the survival of A. cerana.

Advances in materials-based therapeutic strategies against osteoporosis.

Osteoporosis is caused by the disruption in homeostasis between bone formation and bone resorption. Conventional management of osteoporosis involves systematic drug administration and hormonal therapy. These treatment strategies have limited curative efficacy and multiple adverse effects. Biomaterials-based therapeutic strategies have recently emerged as promising alternatives for the treatment of osteoporosis. The present review summarizes the current status of biomaterials designed for managing osteoporosis. The advantages of biomaterials-based strategies over conventional systematic drug treatment are presented. Different anti-osteoporotic delivery systems are concisely addressed. These materials include injectable hydrogels and nanoparticles, as well as anti-osteoporotic bone tissue engineering materials. Fabrication techniques such as 3D printing, electrostatic spinning and artificial intelligence are appraised in the context of how the use of these adjunctive techniques may improve treatment efficacy. The limitations of existing biomaterials are critically analyzed, together with deliberation of the future directions in biomaterials-based therapies. The latter include discussion on the use of combination strategies to enhance therapeutic efficacy in the osteoporosis niche.

A seminal perspective on the role of chondroitin sulfate in biomineralization.

Chondroitin sulfate (CS) is an important extracellular matrix component of mineralized tissues. It participates in biomineralization, osteoblast differentiation and promotes bone tissue repair in vitro. However, the mechanism in which CS functions is unclear. Accordingly, an in-depth investigation of how CS participates in mineralization was conducted in the present study. Chondroitin sulfate was found to directly induce intrafibrillar mineralization of the collagen matrix. The mineralization outcome was dependent on whether CS remained free in the extracellular matrix or bound to core proteins; mineralization only occurred when CS existed in a free state. The efficacy of mineralization appeared to increase with ascending CS concentration. This discovery spurred the authors to identify the cause of heterotopic ossification in the Achilles tendon. Chondroitin sulfate appeared to be a therapeutic target for the management of diseases associated with heterotopic calcification. A broader perspective was presented on the applications of CS in tissue engineering.