Microbial-mineral interaction experiments and density functional theory calculations revealing accelerating effects for the dolomitization of calcite surfaces by organic components

Carbonates represent major sedimentary rocks in on the continental and oceanic crust of Earth and are often closely related to microbial activities. However, the origin of magnesium-containing carbonates, such as dolomites, has not yet been fully resolved and was debated for many years. In order to reveal the specific role of organic components and microbes on the precipitation of magnesium ions, different dolomitization experiments were carried out with various setups for the presence of eight amino acids and microbes. The Gibbs free energy for dehydration of Mg[6(H2O)]2+ and organic‑magnesium complexes (OMC) at the calcite (101¯4) step edges were calculated by density functional theory (DFT). Combined results of X-ray diffraction (XRD), scanning electron microscope-energy disperse spectroscopy (SEM-EDS), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and high resolution transmission electron microscopy (HRTEM) indicated that magnesium ions were incorporated into the crystal lattice of calcite after calcite reacting with organic‑magnesium solutions (OMS). Dolomite was formed on the surface of calcite under the presence of microbes. The Gibbs free energy barrier of asp, glu, gly, thr, tyr, lys, ser, and ala bonding to Mg[6(H2O)]2+ were 17.8, 16.2, 14.8, 16.5, 19.2, 14.5, 19.0, 17.0 kcal/mol, those are lower than that of the direct dehydration of Mg[6(H2O)]2+ of 19.45 kcal/mol. The Gibbs free barrier of OMC bonding at the acute step ([481¯] and [4¯41]) of 29.7/34.25 kcal/mol are lower than that of Mg[6(H2O)]2+ of 32.45/36.7 kcal/mol and the Gibbs free barrier of OMC bonding at the obtuse step ([481¯] and [4¯41]) of 42.07/47.6 kcal/mol are lower than that of Mg[6(H2O)]2+ of 55.4/60.34 kcal/mol. The enhancing effects of organic components and microbes on the precipitation of magnesium ions were collectively determined through experimental and theoretical calculation, thus setting up a new direction for future studies of dolomitization with a focus on microbial- mineral interactions.

Clinical significance of KRT7 in bladder cancer prognosis

BACKGROUND

Typically, the overexpressed keratin 7 (KRT7) is considered a validated therapeutic target and prognosis marker in bladder cancer. However, the crucial roles of KRT7 in the clinical prognosis and immune microenvironment in bladder cancer remain unclear.

METHODS

Initially, the expression levels of KRT7 in public databases were analyzed that is,Tumor Immune Estimation Resource (TIMER) 2.0 and Gene Expression Profiling Interactive Analysis (GEPIA). Further, the clinical tissue samples from patients (n = 10 pairs) were collected to confirm the expression trends of KRT7 and detected by immunohistochemistry (IHC) analysis. Meanwhile, the relationship between KRT7 and the prognosis of bladder cancer patients was analyzed by Kaplan-Meier plotter estimation and Cox regression analysis. Finally, TIMER 2.0 and IHC staining analyses were performed to calculate the infiltration abundances of three kinds of immune cells in eligible bladder tumor samples.

RESULTS

The TIMER 2.0 and GEPIA datasets suggested the differences in the expression levels of KRT7 in tumors, in which KRT7 was significantly upregulated in bladder cancer. The KRT7 expression was closely associated with patients' gender, tumor histologic subtypes, T status, and American Joint Committee on Cancer stages. Notably, the increased KRT7 indicated poor overall survival and disease-free survival rates. Moreover, KRT7 expression could be responsible for immune infiltration in the cancer microenvironment of the bladder. Finally, the high expression level of KRT7 increased the presence of regulatory T cells (Tregs) but reduced the infiltration of CD8+ T and natural killer cells.

CONCLUSION

KRT7 as a biomarker potentiated the prediction of bladder cancer prognosis and the immune microenvironment.

Dual-Active-Sites Single-Atom Catalysts for Advanced Applications

Dual-Active-Sites Single-Atom catalysts (DASs SACs) are not only the improvement of SACs but also the expansion of dual-atom catalysts. The DASs SACs contains dual active sites, one of which is a single atomic active site, and the other active site can be a single atom or other type of active site, endowing DASs SACs with excellent catalytic performance and a wide range of applications. The DASs SACs are categorized into seven types, including the neighboring mono metallic DASs SACs, bonded DASs SACs, non-bonded DASs SACs, bridged DASs SACs, asymmetric DASs SACs, metal and nonmetal combined DASs SACs and space separated DASs SACs. Based on the above classification, the general methods for the preparation of DASs SACs are comprehensively described, especially their structural characteristics are discussed in detail. Meanwhile, the in-depth assessments of DASs SACs for variety applications including electrocatalysis, thermocatalysis and photocatalysis are provided, as well as their unique catalytic mechanism are addressed. Moreover, the prospects and challenges for DASs SACs and related applications are highlighted. The authors believe the great expectations for DASs SACs, and this review will provide novel conceptual and methodological perspectives and exciting opportunities for further development and application of DASs SACs.

Polyhedron-Like Biomaterials for Innervated and Vascularized Bone Regeneration

Neural-vascular networks are densely distributed through periosteum, cortical bone, and cancellous bone, which is of great significance for bone regeneration and remodeling. Although significant progress has been made in bone tissue engineering, ineffective bone regeneration, and delayed osteointegration still remains an issue due to the ignorance of intrabony nerves and blood vessels. Herein, inspired by space-filling polyhedra with open architectures, polyhedron-like scaffolds with spatial topologies are prepared via 3D-printing technology to mimic the meshwork structure of cancellous bone. Benefiting from its spatial topologies, polyhedron-like scaffolds greatly promoted the osteogenic differentiation of bone mesenchymal stem cells (BMSCs) via activating PI3K-Akt signals, and exhibiting satisfactory performance on angiogenesis and neurogenesis. Computational fluid dynamic (CFD) simulation elucidates that polyhedron-like scaffolds have a relatively lower area-weighted average static pressure, which is beneficial to osteogenesis. Furthermore, in vivo experiments further demonstrate that polyhedron-like scaffolds obviously promote bone formation and osteointegration, as well as inducing vascularization and ingrowth of nerves, leading to innervated and vascularized bone regeneration. Taken together, this work offers a promising approach for fabricating multifunctional scaffolds without additional exogenous seeding cells and growth factors, which holds great potential for functional tissue regeneration and further clinical translation.

Xonotlite Nanowire-Containing Bioactive Scaffolds for the Therapy of Defective Adipose Tissue in Breast Cancer

Considering the challenge in the treatment of severe breast tumor patients, xonotlite nanowire-containing bioactive scaffolds (Fe3O4-CS-GelMA) were fabricated by the 3D-printing technique for the therapy of injured adipose tissue after surgery. Importantly, benefiting from the excellent magnetothermal performance of Fe3O4 microspheres, Fe3O4-CS-GelMA scaffolds could effectively kill tumor cells in vitro and suppress breast cancer in vivo under an alternating magnetic field, and the tumor did not recur in 2 weeks. In addition, attributed to the released bioactive inorganic ions, Fe3O4-CS-GelMA composite scaffolds could effectively promote the expression of adipogenesis-related genes and proteins of adipose-derived stem cells (ADSCs) via the PI3K-AKT signaling pathway in vitro. Furthermore, Fe3O4-CS-GelMA scaffolds with ADSCs could obviously stimulate the formation of adipose in vivo, compared with that of pure GelMA without inorganic components. Therefore, this study offers a promising strategy for the therapy of breast tumors after the surgical excision of breast carcinoma.

Optimized synthesis of anti-COVID-19 drugs aided by retrosynthesis software

Considering the millions of COVID-19 patients worldwide, a global critical challenge of low-cost and efficient anti-COVID-19 drug production has emerged. Favipiravir is one of the potential anti-COVID-19 drugs, but its original synthetic route with 7 harsh steps gives a low product yield (0.8%) and has a high cost ($68 per g). Herein, we demonstrated a low-cost and efficient synthesis route for favipiravir designed using improved retrosynthesis software, which involves only 3 steps under safe and near-ambient air conditions. A yield of 32% and cost of $1.54 per g were achieved by this synthetic route. We also used the same strategy to optimize the synthesis of sabizabulin. We anticipate that these synthetic routes will contribute to the prevention and treatment of COVID-19.

3D printing of conch-like scaffolds for guiding cell migration and directional bone growth

Regeneration of severe bone defects remains an enormous challenge in clinic. Developing regenerative scaffolds to directionally guide bone growth is a potential strategy to overcome this hurdle. Conch, an interesting creature widely spreading in ocean, has tough spiral shell that can continuously grow along the spiral direction. Herein, inspired by the physiological features of conches, a conch-like (CL) scaffold based on β-TCP bioceramic material was successfully prepared for guiding directional bone growth via digital light processing (DLP)-based 3D printing. Benefiting from the spiral structure, the CL scaffolds significantly improved cell adhesion, proliferation and osteogenic differentiation in vitro compared to the conventional 3D scaffolds. Particularly, the spiral structure in the scaffolds could efficiently induce cells to migrate from the bottom to the top of the scaffolds, which was like “cells climbing stairs”. Furthermore, the capability of guiding directional bone growth for the CL scaffolds was demonstrated by a special half-embedded femoral defects model in rabbits. The new bone tissue could consecutively grow into the protruded part of the scaffolds along the spiral cavities. This work provides a promising strategy to construct biomimetic biomaterials for guiding directional bone tissue growth, which offers a new treatment concept for severe bone defects, and even limb regeneration.

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A conch-like scaffold was firstly developed for guiding directional bone growth.

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The CL scaffolds efficiently induced cells “climbing stairs”- like-migrating.

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The CL scaffolds showed improved bioactivities benefited from the spiral structure.

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This work provided a new treatment concept for severe bone defects.

Hydrogenation Reactions with Synergistic Catalysis of Pd single atoms and nanoparticles under Near-Ambient Conditions

Due to the limited resources and high cost of noble metals, boosting their catalytic activities is highly desired in the current catalysis industry. Here, we report a synergetic catalyst, combining Pd²⁺ and Pd⁰ species in a nitrogen-doped porous carbons (NPC), which shows boosted catalytic activities in hydrogenation reactions of organic nitro compounds (nitrobenzene, 4-nitrophenol, 1-nitronaphthalene and 1-nitropropane) under near ambient conditions. This synergetic catalyst NPC-[Pd] was synthesized by partial reduction of a palladium-loaded NPC. The catalytic activities and selectivity of NPC-[Pd] for hydrogenation were enhanced significantly compared with those of NPC-Pd²⁺ or NPC-Pd⁰ nanoparticles. Theoretical calculations show that H₂ preferentially dissociates on Pd nanoparticles, and then organic molecules (nitrobenzene) can be captured and react with the dissociated H atom on Pd²⁺ sites. Similar reaction procedure also occur on Pt or Rh. Hydrogenation of different aromatic compounds with different functional groups (naphthalene, 4-nitrochlorobenzene, benzaldehyde and acetophenone) confirmed the broad excellent catalytic activity of this synergistic catalyst.

MXene-Derived Metal-Organic Framework@MXene Heterostructures toward Electrochemical NO Sensing

The electrochemical sensing of nitric oxide (NO) molecules by metal-organic framework (MOF) catalysts has been impeded, to a large extent, owing to their poor electrical conductivity and weak NO adsorption. In this work, incomplete in situ conversion of V₂ CT_x (T = terminal atoms) MXene to MOF is adopted, forming MOF@MXene heterostructures, which outperform MXene and MOF monocomponents toward electrochemical NO sensing. Density functional theory (DFT) calculation results indicate metal-like electronic characters for the heterostructure benefiting from the dominating contribution of the V 3d orbitals of the metallic MXene. Moreover, plane-averaged charge density difference shows substantial charge redistribution occurs at the heterointerfaces, producing a built-in field, which facilitates charge transfer. Besides, molecular mechanics-based simulated annealing calculation reveals greatly enhanced adsorption energies of NO molecules on the heterointerfaces than that on separate MOFs and MXenes. Hence, the facilitated charge transfer and preferential NO adsorption are responsible for the dramatically promoted performance toward NO sensing. The prudent design of MOF@MXene heterostructure may spur advanced electrocatalysts for electrochemical sensing.

Complement system-related genes in stomach adenocarcinoma: Prognostic signature, immune landscape, and drug resistance

Stomach adenocarcinoma (STAD) is one of the most common malignant tumors of the digestive tract, and its survival predictors are critical for precision medicine but have not been fully investigated. The complement system is a complex multistep cascade at the interface of innate and adaptive immunity, which augments the function of antibodies and phagocytes. This study aimed to construct and validate a CSRG signature based on TCGA (The Cancer Genome Atlas) STAD dataset and revalidated it in an external GEO (Gene Expression Omnibus) STAD cohort. Subsequently, we assessed the association of risk levels with the stromal and immune cell infiltration level in STAD using the ESTIMATE, single-sample Gene Set Enrichment Analysis (ssGSEA), and Microenvironment Cell Populations-counter (MCP-counter) algorithm. It was found that the CSRG signature, based on three genes (SERPINE1, PROC, and CFHR3), was significantly and independently associated with the OS in TCGA STAD patients (p < 0.001). Subsequently, we found that the high-risk STAD harbors more immune cell infiltration than the low-risk group, and the ESTIMATE results indicated that there exists a more stromal component in the tumor microenvironment of the high-risk groups. Compared to the low-risk group, the high-risk STAD patients had higher expressions of marker genes for immune checkpoint inhibitors (ICIs) and showed higher sensitivity to the chemotherapy agents (rapamycin, nilotinib, 5-fluorouracil, axitinib, DMOG, and JNK inhibitor VIII). The prognostic value of the CSRGs was further validated by nomogram plots, which revealed that it was superior to tumor TNM and pathologic stage. Finally, the three expression levels were evaluated in GES-1, HGC27, and AGS cells by qRT-PCR.

First-principles study of CO2 hydrogenation to formic acid on single-atom catalysts supported on SiO2

The hydrogenation of CO₂ into valuable chemical fuels reduces the atmospheric CO₂ content and also has broad economic prospects. Support is essential for catalysts, but many of the reported support materials cannot meet the requirements of accessibility and durability. Herein, we theoretically designed a series of single-atom noble metals anchored on a SiO₂ surface for CO₂ hydrogenation using density functional theory (DFT) calculations. Through theoretical evaluation of the formation energy, hydrogen dissociation capacity, and activity of CO₂ hydrogenation, we found that Ru@SiO₂ is a promising candidate for CO₂ hydrogenation to formic acid. The energy barrier of the rate-determining step of the entire conversion process is 23.9 kcal mol^-1; thus, the reaction can occur under mild conditions. In addition, active and stable origins were revealed through electronic structure analysis. The charge of the metal atom is a good descriptor of the catalytic activity. The Pearson correlation coefficient (PCC) between metal charge and its CO₂ hydrogenation barrier is 0.99. Two solvent models were also used to investigate hydrogen spillover processes and the reaction path was searched by the climbing image nudged-elastic-band (CI-NEB) method. The results indicated that the explicit solvent model could not be simplified into a few solvent molecules, leading to a large difference in the reaction paths. This work will serve as a reference for the future design of more efficient catalysts for CO₂ hydrogenation.

Bioinspired Laminated Bioceramics with High Toughness for Bone Tissue Engineering

For the research of biomaterials in bone tissue engineering, it is still a challenge to fabricate bioceramics that overcome brittleness while maintaining the great biological performance. Here, inspired by the toughness of natural materials with hierarchical laminated structure, we presented a directional assembly-sintering approach to fabricate laminated MXene/calcium silicate-based (L-M/CS) bioceramics. Benefiting from the orderly laminated structure, the L-M/CS bioceramics exhibited significantly enhanced toughness (2.23 MPa·m^1/2) and high flexural strength (145 MPa), which were close to the mechanical properties of cortical bone. Furthermore, the L-M/CS bioceramics possessed more suitable degradability than traditional CaSiO₃ bioceramics due to the newly formed CaTiSiO₅ after sintering. Moreover, the L-M/CS bioceramics showed good biocompatibility and could stimulate the expression of osteogenesis-related genes. The mechanism of promoting osteogenic differentiation had been shown to be related to the Wnt signaling pathway. This work not only fabricated calcium silicate-based bioceramics with excellent mechanical and biological properties for bone tissue engineering but also provided a strategy for the combination of bionics and bioceramics.

Rational Design of Synergistic Structure Between Single-Atoms and Nanoparticles for CO2 Hydrogenation to Formate Under Ambient Conditions

Single-atom catalysts (SACs) as the new frontier in heterogeneous catalysis have attracted increasing attention. However, the rational design of SACs with high catalytic activities for specified reactions still remains challenging. Herein, we report the rational design of a Pd1-PdNPs synergistic structure on 2,6-pyridinedicarbonitrile-derived covalent triazine framework (CTF) as an efficient active site for CO2 hydrogenation to formate under ambient conditions. Compared with the catalysts mainly comprising Pd1 and PdNPs, this hybrid catalyst presented significantly improved catalytic activity. By regulating the ratio of Pd1 to PdNPs, we obtained the optimal catalytic activity with a formate formation rate of 3.66 molHCOOM·molPd−1·h−1 under ambient conditions (30°C, 0.1 MPa). Moreover, as a heterogeneous catalyst, this hybrid catalyst is easily recovered and exhibits about a 20% decrease in the catalytic activity after five cycles. These findings are significant in elucidating new rational design principles for CO2 hydrogenation catalysts with superior activity and may open up the possibilities of converting CO2 under ambient conditions.

A security-aware service function chain deployment method for load balance and delay optimization

Network function virtualization (NFV) decouples network functions from hardware devices. However, it introduces security challenges due to its reliance on software, which facilitates attacks. This security problem has a significant negative impact on the interests of users. Existing deployment methods are not suitable for SFC requests with a security demand, causing the use of substrate resources unreasonable and lower acceptance ratio. Moreover, a strict delay requirement is another challenge for NFV. To make the use of the substrate resources more reasonable and reduce the transmission delay, this paper proposes a security-constraint and function-mutex-constraint consolidation (SFMC) method for virtual network function (VNF) to reduce resource consumption and transmission delay. In addition, a security-aware service function chain (SASFC) deployment method for load balance and delay optimization is presented, which deploys service function chains according to the consolidated results of the SFMC method. The SASFC method first obtains a candidate server node set using resource, hosting capacity, security and node load constraints. It then obtains candidate paths according to the metric of the minimum transmission delay and link load constraint using the Viterbi algorithm. Finally, the path with the highest VNF security level match degree among the candidate paths is adopted to deploy virtual links, and the corresponding server nodes are employed to deploy VNFs. As a result, the SASFC method makes the use of substrate resources more reasonable. It improves the acceptance ratio and long-term average revenue to cost ratio, reduces transmission delay, and achieves load balancing. Experiment results show that when the number of VNFs is five, the acceptance ratio and long-term average revenue to cost ratio of the SASFC method are close to 0.75 and 0.88, which are higher than those of the compared methods. Its transmission delay and proportion of bottleneck nodes are 7.71 and 0.024, which are lower than those of the compared methods. The simulations demonstrate the effectiveness of the SASFC method.

3D printing of sponge spicules-inspired flexible bioceramic-based scaffolds

Bioceramics are widely used in bone tissue repair and regeneration due to their desirable biocompatibility and bioactivity. However, the brittleness of bioceramics results in difficulty of surgical operation, which greatly limits their clinical applications. The spicules of the marine sponge Euplectella aspergillum (Ea) possess high flexibility and fracture toughness resulting from concentric layered silica glued by a thin organic layer. Inspired by the unique properties of sponge spicules, flexible bioceramic-based scaffolds with spicule-like concentric layered biomimetic microstructures were constructed by combining two-dimensional (2D) bioceramics and 3D printing. 2D bioceramics could be assembled and aligned by modulating the shear force field in the direct ink writing (DIW) of 3D printing. The prepared spicules-inspired flexible bioceramic-based (SFB) scaffolds differentiated themselves from traditional 3D-printed irregular particles-based bioceramic-based scaffolds as they could be adaptably compressed, cut, folded, rolled and twisted without the occurrence of fracture, significantly breaking through the bottleneck of inherent brittleness of traditional bioceramic scaffolds. In addition, SFB scaffolds showed significantly enhanced in vitro and in vivo bone-forming bioactivity as compared to conventional β-tricalcium phosphate (β-TCP) scaffolds, suggesting that SFB scaffolds combined both of excellent mechanical and bioactive characteristics, which is believed to greatly promote the bioceramic science and their clinical applications.

A robust mechanism for resetting juvenility during each generation in Arabidopsis

Multicellular organisms undergo several developmental transitions during their life cycles. In contrast to animals, the plant germline is derived from adult somatic cells. As such, the juvenility of a plant must be reset in each generation. Previous studies have demonstrated that the decline in the levels of miR156/7 with age drives plant maturation. Here we show that the resetting of plant juvenility during each generation is mediated by de novo activation of MIR156/7 in Arabidopsis. Blocking this process leads to a shortened juvenile phase and premature flowering in the offspring. In particular, an Arabidopsis plant devoid of miR156/7 flowers even without formation of rosette leaves in long days. Mechanistically, we find that different MIR156/7 genes are reset at different developmental stages through distinct reprogramming routes. Among these genes, MIR156A, B and C are activated de novo during sexual reproduction and embryogenesis, while MIR157A and C are reset upon seed germination. This redundancy generates a robust reset mechanism that ensures accurate restoration of the juvenile phase in each plant generation.

Low-dose three-dimensional CT angiography for the evaluation of posterolateral protrusion of the vertebral artery over the posterior arch of the atlas: a quantitative anatomical comparison study of the rotational and neutral positions

AIM

To investigate the changes in relevant anatomical parameters of posterolateral protrusion of the vertebral artery (VA) between head-neck rotational and neutral positions using low-dose three-dimensional computed tomography angiography (3D-CTA).

MATERIALS AND METHODS

Low-dose 3D-CTA images obtained for various craniocervical diseases in 36 non-dominant VA side patients with neutral, left and right head-neck rotational positions were evaluated. The relevant parameters from superior and inferior views, including external diameter (ED), internal diameter (ID), transverse diameter (TD), heights and diameters of posterolateral protrusion of the VA over the posterior arch of the atlas in the neutral and rotational positions, were recorded and compared.

RESULTS

There was no significant differences in the rotational angle (left/right: 31.23 ± 6.60/29.94 ± 6.09°, p>0.05). There were no significant differences in heights and diameters of bilateral VA between rotational and neutral positions (all p>0.05). The contralateral ID, ED, and TD of the rotational positions were significantly shorter than those of the neutral position (all p<0.05), while there were no significant differences in the three ipsilateral diameters (all p>0.05).

CONCLUSIONS

Posterolateral protrusion of the VA is not uncommon in the population, and surgeons should be aware of its presence, especially the increased possibility of injury to the VA caused by head-neck rotation, during the operation; thus, preoperative evaluation by low-dose 3D-CTA should be considered.

Synergetic effect between Pd2+ and Ir4+ species promoting direct ethane dehydrogenation into ethylene over bimetallic PdIr/AC catalysts

This work reported the efficient Pd–Ir pairs on the Pd7Ir2/AC-B catalyst achieved a TOF (C2H4) of 756.6 h−1 at 500 °C, and the direct ethane dehydrogenation (EDH) rationale and deactivation mechanism were proposed.

Flavanthrene derivatives as photostable and efficient singlet exciton fission materials

Singlet exciton fission (SF) is believed to have the potential to break the Shockley−Quiesser third-generation solar cell devices, so that attracted great attention. Conventional linear acene based SF materials generally...

In Silico Design of Metal-Free Hydrophosphate Catalysts for Hydrogenation of CO2 to Formate

CO2 reduction by H2 using metal-free catalysts is highly challenging. Frustrated Lewis pairs (FLPs) have been considered potential metal-free catalysts for this reaction. However, most FLPs are unstable, which limits...

Microbially Catalyzed Biomaterials for Bone Regeneration

Bone is a complex mineralized tissue composed of various organic (proteins, cells) and inorganic (hydroxyapatite, calcium carbonate) substances with micro/nanoscale structures. To improve interfacial bioactivity of bone-implanted biomaterials, extensive efforts are being made to fabricate favorable biointerface via surface modification. Inspired by microbially catalyzed mineralization, a novel concept to biologically synthesize the micro/nanostructures on bioceramics, microbial-assisted catalysis, is presented. It involves three processes: bacterial adhesion on biomaterials, production of CO₃ ^2- assisted by bacteria, and nucleation and growth of CaCO₃ nanocrystals on the surface of bioceramics. The microbially catalyzed biominerals exhibit relatively uniform micro/nanostructures on the surface of both 2D and 3D α-CaSiO₃ bioceramics. The topographic and chemical cues of the grown micro/nanostructures present excellent in vitro and in vivo bone-forming bioactivity. The underlying mechanism is closely related to the activation of multiple biological processes associated with bone regeneration. The study offers a microbially catalytic concept and strategy of fabricating micro/nanostructured biomaterials for tissue regeneration.

Isolated Single-Atom Ni-N5 Catalytic Site in Hollow Porous Carbon Capsules for Efficient Lithium-Sulfur Batteries

Lithium-sulfur (Li-S) batteries suffer from multiple complex and often interwoven issues, such as the low electronic conductivity of sulfur and Li₂S/Li₂S₂, shuttle effect, and sluggish electrochemical kinetics of lithium polysulfides (LiPSs). Guided by theoretical calculations, a multifunctional catalyst of isolated single-atom nickel in an optimal Ni-N₅ active moiety incorporated in hollow nitrogen-doped porous carbon (Ni-N₅/HNPC) is constructed and acts as an ideal host for a sulfur cathode. The host improved electrical conductivity, enhanced physical-chemical dual restricting capability toward LiPSs, and, more importantly, boosted the redox reaction kinetics by the Ni-N₅ active moiety. Therefore, the Ni-N₅/HNPC/S cathode exhibits superior rate performance, long-term cycling stability, and good areal capacity at high sulfur loading. This work highlights the important role of the coordination number of active centers in single-atom catalysts and provides a strategy to design a hollow nanoarchitecture with single-atom active sites for high-performance Li-S batteries.

3D Printing of Black Bioceramic Scaffolds with Micro/Nanostructure for Bone Tumor-Induced Tissue Therapy

It is common to improve the relevant performance in the field of energy storage materials or catalytic materials by regulating the number of defects. However, there are few studies on the biomaterials containing defects for tissue engineering. Herein, a new type of defect-rich scaffolds, black akermanite (B-AKT) bioceramic scaffolds with micro/nanostructure, the thickness of which is from 0.14 to 1.94 µm, is fabricated through introducing defects on the surface of bioceramic scaffolds. The B-AKT scaffolds have advantages on the degradation rate and the osteogenic capacity over the AKT (Ca₂ MgSi₂ O₇ ) scaffolds due to the surface defects which stimulate the osteogenic differentiation of rabbit bone mesenchymal stem cells via activating bone morphogenetic protein 2 （BMP2） signaling pathway and further promote bone formation in vivo. In addition, the prepared B-AKT scaffolds, the temperature of which can be over 100 °C under the near infrared （NIR） irradiation (0.66 W cm^-2 ), possess excellent performance on photothermal and antitumor effects. The work develops an introducing-defect strategy for regulating the biological performance of bioceramic scaffolds, which is expected to be applied in the next generation of bioceramic scaffolds for regenerative medicine.

In Silico Design of Covalent Organic Framework-Based Electrocatalysts

Covalent organic frameworks (COFs) are an emerging type of porous crystalline material for efficient catalysis of the oxygen evolution reaction (OER). However, it remains a grand challenge to address the best candidates from thousands of possible COFs. Here, we report a methodology for the design of the best candidate screened from 100 virtual M-N _x O _y (M = 3d transition metal)-based model catalysts via density functional theory (DFT) and machine learning (ML). The intrinsic descriptors of OER activity of M-N _x O _y were addressed by the machine learning and used for predicting the best structure with OER performances. One of the predicted structures with a Ni-N₂O₂ unit is subsequently employed to synthesize the corresponding Ni-COF. X-ray absorption spectra characterizations, including XANES and EXAFS, validate the successful synthesis of the Ni-N₂O₂ coordination environment. The studies of electrocatalytic activities confirm that Ni-COF is comparable with the best reported COF-based OER catalysts. The current density reaches 10 mA cm^-2 at a low overpotential of 335 mV. Furthermore, Ni-COF is stable for over 65 h during electrochemical testing. This work provides an accelerating strategy for the design of new porous crystalline-material-based electrocatalysts.

3D-printed bioceramic scaffolds with Fe3S4microflowers for magnetothermal and chemodynamic therapy of bone tumor and regeneration of bone defects

Elimination of residual osteosarcoma cells and repair of bone defects remain major challenges for osteosarcoma in clinic. To address this problem, it is required that multifunctional therapeutic platform possess high tumor-killing efficiency and simultaneous bone regeneration capabilities. In this work, an intelligent therapeutic platform was developed to achieve highly-efficient tumor therapy and simultaneous significantly improved bone defect repairing ability, which was realized byin situgrowing ferromagnetic Fe₃S₄layers with tuned microstructures on the surface of 3D-printed akermanite bioceramic scaffolds via hydrothermal method. The Fe₃S₄layers exploited magnetic thermal energy to enhance chemodynamic treatment, thus achieving a synergistic effect between magnetothermal and chemodynamic therapy on the elimination of residual tumor cells. Moreover, the micro-structured surface of the 3D-printed bioceramic scaffolds further enhanced the osteogenic activityin vitroand accelerated the bone regenerationin vivo. The scaffolds with multi-mode tumor-killing and bone repairing capabilities indicated that such a therapeutic platform is applicable for a stepwise treatment strategy of osteosarcoma and provides inspiration for the design of multifunctional biomaterials.

A Porphyrin-Based Covalent Organic Framework for Metal-Free Photocatalytic Aerobic Oxidative Coupling of Amines

Imine is an important intermediate in drug synthesis. Photocatalytic aerobic oxidative coupling of amines has been considered as a clean and promising way to produce imine and attracted great attentions. Herein, we designed and synthesized a novel two-dimensional porphyrin-based COF (Por-BC-COF) which adopts an AA stacking mode with excellent crystallinity, high Brunauer-Emmett-Teller surface areas (1200 m 2 g -1 ), wide light absorption range (200-1300 nm) and good stability in a variety of organic solvents. Por-BC-COF can be used as a metal-free heterogeneous photocatalyst for the photocatalytic oxidation of amines to imines under visible light and red light with a high yield (97%). This work presents a novel and efficient COF photocatalyst in the application of light-driven organic synthesis.

e-Graphene: A Computational Platform for the Prediction of Graphene-Based Drug Delivery System by Quantum Genetic Algorithm and Cascade Protocol

Graphene, as a novel category of carbon nanomaterials, has attracted a great attention in the field of drug delivery. Due to its large dual surface area, graphene can efficiently load drug molecules with high capacity via non-covalent interaction without chemical modification of the drugs. Hence, it ignites prevalent interests in developing a new graphene/graphene oxide (GO)-based drug delivery system (GDDS). However, current design of GDDS primarily depends on the prior experimental experience with the trial-and-error method. Thus, it is more appealing to theoretically predict possible GDDS candidates before experiments. Toward this end, we propose to fuse quantum genetic algorithm (QGA) and quantum mechanics (QM)/semi-empirical quantum mechanics (SQM)/force field (FF) to globally search the optimal binding interaction between the graphene/GO and drug in a given GDDS and develop a free computational platform “e-Graphene” to automatically predict/screen potential GDDS candidates. To make this platform more pragmatic for the rapid yet relatively accurate prediction, we further propose a cascade protocol via firstly conducting a fast QGA/FF calculation with fine QGA parameters and automatically passing the best chromosomes from QGA/FF to initialize a higher level QGA/SQM or QGA/QM calculation with coarse QGA parameters (e.g., small populations and short evolution generations). By harnessing this platform and protocol, systematic tests on a typical GDDS containing an anticancer drug SN38 illustrate that high fabrication rates of hydroxyl, epoxy, and carboxyl groups on a pristine graphene model will compromise the stability of GDDS, implying that an appropriate functionalization rate is crucial for the delicate balance between the stability and solubility/biocompatibility of GDDS. Moreover, automatic GDDS screen in the DrugBank database is performed and elicits four potential GDDS candidates with enhanced stability than the commonly tested GDDS containing SN38 from the computational point of view. We hope that this work can provide a useful program and protocol for experimental scientists to rationally design/screen promising GDDS candidates prior to experimental tests.

[LIM-domain binding protein 2 regulated by m6A modification inhibits lung adenocarcinoma cell proliferation in vitro]

OBJECTIVE

To investigate the role and expression pattern of LIM-domain binding protein 2 (LDB2) in lung adenocarcinoma.

OBJECTIVE

We studied the expression pattern of LDB2 in lung adenocarcinoma based on data from the online databases TCGA, GEO and CPTAC, and the results were verified in lung adenocarcinoma tissues and cells using immunohistochemistry, qRT-PCR and Western blotting. The relationship between LDB2 and the prognosis of patients with lung adenocarcinoma was analyzed using GEPIA and GEO databases. We further analyzed the role of LDB2 in regulating cell behaviors in a H1299 cell model over-expressing LDB2 using cell counting, soft agar colony forming assay and flow cytometry. The m⁶A binding sites on LDB2 were confirmed by bioinformatics analysis and MeRIP-qPCR assays. The effect of YTHDC2 on LDB2 was examined using qRT-PCR and Western blotting, and the binding of YTHDC2 to the transcript of LDB2 was verified with RIP-qPCR assays. Dual luciferase reporter assay was performed to verify YTHDC2 functioning via m⁶A sites.

OBJECTIVE

LDB2 expression was significantly decreased in lung adenocarcinoma in comparison with normal tissues based on data from TCGA, GEPIA and CPTAC, and the same results were obtained from 80 lung adenocarcinoma tissues and 17 adjacent normal tissues. Similarly, LDB2 expression was decreased in lung adenocarcinoma cells as compared with 16HBE cells. The data from Prognoscan and GEPIA suggested that a high LDB2 expression was positively correlated with a more favorable outcome of lung adenocarcinoma patients. LDB2-overexpressing H1299 cells showed a significant inhibition of proliferative activity with cell cycle arrest in S phage. Bioinformatics analysis and MeRIP-qPCR assay confirmed the presence of m⁶A sites on LDB2. The m⁶A reader YTHDC2 was positively related with LDB2 in lung adenocarcinoma based on data from GEPIA (r=0.22). Overexpression YTHDC2 significantly enhanced LDB2 expression in H1299 cells by about 19.35 folds. Dual luciferase reporter assay showed that YTHDC2 enhanced the promoter activity in the wild-type group but not in deletion group.

OBJECTIVE

LDB2 expression can be up-regulated by m⁶A reader YTHDC2 in lung adenocarcinoma to inhibit the proliferation of the tumor cells in vitro.

Three-Dimensional Printing of Scaffolds with Synergistic Effects of Micro-Nano Surfaces and Hollow Channels for Bone Regeneration

The 3D printing technology with unique strategies for accurate fabrication of biomaterials in regenerative medicine has been widely applied in bone regeneration. However, the traditional 3D printing scaffolds are only stacked by solid struts without any hollow channel structures, which limits the new bone tissue formation. In this study, a special 3D scaffold with hollow channels and a micro-nano surface was prepared by a modified 3D printing strategy combined with the hydrothermal treatment approach. By regulating the reaction solution of hydrothermal treatment, the micro-nano structures formed on the surface of scaffolds can be successfully controlled. Moreover, the scaffolds have the ability to facilitate the attachment and proliferation of BMSCs after culturing for 1, 3, and 7 days in vitro. Interestingly, the in vivo results demonstrated that the hollow channels and the micro-nano surface present synergistic effects on bone regeneration. They both boost the new bone formation in femur defects in rabbits for 12 weeks after operation. The study demonstrates a 3D scaffold with special surface microstructures and hollow struts that can overcome the shortages of most traditional scaffolds and meanwhile improve the bioactivity of biomaterials for bone tissue engineering.

Co-inspired hydroxyapatite-based scaffolds for vascularized bone regeneration

Hydroxyapatite (HA) is the main inorganic component of human bone. Inspired by nacre and cortical bone, hydroxyapatite-based coil scaffolds were successfully prepared. The scaffolds presented "brick and mortar" multi-layered structure of nacre and multi-layered concentric circular structure of cortical bone. Because of bioactive components and hierarchical structure, the scaffolds possessed good compressive strength (≈95 MPa), flexural strength (≈161 MPa) and toughness (≈1.1 MJ/m³). In addition, they showed improved angiogenesis and osteogenesis in rat and rabbit critical sized bone defect models. By mimicking co-biological systems, this work provided a feasible strategy to optimize the properties of traditional tissue engineering biological materials for vascularized bone regeneration.

Bone cements for therapy and regeneration for minimally invasive treatment of neoplastic bone defects

Although calcium phosphate cements (CPCs) have been clinically used to repair bone defects caused by bone tumor resection, traditional CPCs cannot kill the remaining tumor cells after surgery and prevent cancer recurrence. In this study, a multifunctional injectable metal-organic framework (MOF) cobalt coordinated tetrakis(4-carboxyphenyl)porphyrin (Co-TCPP)-modified calcium phosphate cement (Co-TCPP/CPC) was prepared for the minimally invasive treatment of neoplastic bone defects. The incorporation of Co-TCPP not only retained the good injectability of bone cements, but also shortened the setting time, improved the compressive strength, and endowed them with excellent photothermal properties. The hyperthermia effect induced by the presence of Co-TCPP well induced the therapeutic effect against bone tumors both in vitro and in vivo. Moreover, Co-TCPP/CPC exhibited desirable osteogenesis and angiogenesis by promoting bone and vascular regeneration in vivo. Therefore, the Co-TCPP composite bone cement demonstrated its great potential for bone tumor therapy and tissue regeneration, representing a multifunctional biomaterial for the treatment of neoplastic bone defects.

A dramatic conformational effect of multifunctional zwitterions on zeolite crystallization

Carnitine functions as a mesoporogen in LTA zeolite synthesis whereas its structural analogue acetylcarnitine acts as a crystal growth modifier. An array of experimental and theoretical studies reveal a remarkable effect of molecular conformation on the actual roles of organic functional groups during zeolite crystallization.

Nanosized concave pit/convex dot microarray for immunomodulatory osteogenesis and angiogenesis

The immunomodulatory capability of biomaterials is of paramount importance for successful material-mediated bone regeneration. Particularly, the design of surface nano-topography can be leveraged to instruct immune reactions, yet the understanding of such "nano-morphology effect" is still very limited. Herein, highly ordered nano-concave pit (denoted as NCPit) and nano-convex dot (denoted as NCDot) microarrays with two different sizes were successfully constructed on a 316LSS surface via anodization and subsequently immersion-coating treatment, respectively. We, for the first time, comparatively investigated the interactions of NCPit and NCDot microarrays with RAW264.7 macrophages and their immunomodulatory impacts on osteogenesis and angiogenesis of human bone mesenchymal stem cells (hBMSCs) and human umbilical vein endothelial cells (HUVECs). NCDot microarrays induced macrophages towards M2 polarization with the higher expression level of anti-inflammatory markers (IL-10 and CD 206) and the lower level of pro-inflammatory markers (TNF-α, IL-1β, IL-6 and CD 86) than those of the corresponding NCPit microarrays. During the process, the expressions of osteogenesis-related genes (Runx2, OPN and OCN) of hBMSCs, and angiogenesis-related genes (eNOS, HIF-1α, KDR and VEGF) of HUVECs were significantly upregulated by the NCDot microarray-modulating immune microenvironment of macrophages, and finally stimulated osteogenesis and angiogenesis. Thus, the prepared NCDot arrays were able to significantly promote osteo-/angiogenic activity by generating a more suitable immune microenvironment than NCPit arrays, offering substantial evidence for designing immunomodulatory biomaterials with specific microstructures and optimal bioactivity.

Multifunctional bioactive Nd-Ca-Si glasses for fluorescence thermometry, photothermal therapy, and burn tissue repair

Photothermal therapy (PTT), an emerging tumor treatment technology, has attracted tremendous interest, but excessive heat will cause damage to surrounding healthy tissues. Therefore, in situ temperature monitoring during PTT is of great importance to determine optimal treatment temperature and repair heat-damaged normal tissues. Here, we report the preparation of multifunctional Nd-Ca-Si silicate glasses and glass/alginate composite hydrogels that not only have photothermal property but also emit fluorescence under 808-nm laser irradiation, and its fluorescence intensity is linearly correlated with in situ temperature. With this feature, optimal PTT temperature for effective tumor treatment with minimal normal tissue damage can be obtained. In addition, because of the bioactive silicate components, the composite hydrogel has bioactivity to repair heat damage caused by PTT. This implantable multifunctional material with unique temperature monitoring, photothermal function, and wound healing bioactivity can be used for localized thermal therapy.

Salen-Based Conjugated Microporous Polymers for Efficient Oxygen Evolution Reaction

Exploring high-performance electrocatalysts, especially non-noble metal electrocatalysts, for the oxygen evolution reaction (OER) is critical to energy storage and conversion. Herein, we report for the first time that conjugated microporous polymers (CMPs) incorporating salen can be used as OER electrocatalysts with outstanding performances. The best OER electrocatalyst (salen-CMP-Fe-3) exhibits a low Tafel slope of 63 mV dec^-1 and an overpotential of 238 mV at 10 mA cm^-2 . DFT and Grand Canonical Monte Carlo calculations confirmed that the significantly improved electrocatalytic properties can be attributed to the intrinsic catalytic activity of the salen moiety and the enrichment effect of the pore structures. This work demonstrates that salen-based conjugated polymers are a type of metal-coordinated porous polymer that show excellent catalyst performance.

Silver-Modified Ba1-xCo0.7Fe0.2Nb0.1O3-δ Perovskite Performing as a Cathodic Catalyst of Intermediate-Temperature Solid Oxide Fuel Cells

A series of silver (Ag)-modified barium cobalt ferrous niobate (Ba_1-xCo_0.7Fe_0.2Nb_0.1O_3-δ, BCFN) materials were fabricated using a solid-state method by doping silver cations into the A-site of this perovskite matrix (Ag-BCFN). The electrochemical analyses indicated that the Ag-BCFN cathodic catalysts performed superior to the nonmodified catalysts when applied in intermediate-temperature solid oxide fuel cells (IT-SOFCs). These Ag-BCFN cathodic catalysts displayed a cubic perovskite structure (PDF 75-0227, Pm3̅m, α = 90°) with a high degree of crystallinity, as demonstrated by X-ray powder diffraction analyses. It was also found that the in situ exsolution of the silver ion (Ag⁺) occurred, where 57.9% of doped Ag⁺ was reduced into metallic Ag particles with size ranging from 5 to 10 nm, as shown by electron microscopic analyses. The cerium gadolinium oxide (Ce_0.9Gd_0.1O_2-δ) electrolyte-supported symmetrical half cell using different Ag-BCFN formulations of Ba_1-xAg_xCo_0.7Fe_0.2Nb_0.1O_3-δ as electrodes showed a polarization resistance as low as 0.233 Ω·cm² and an exchange current density of 85.336 mA·cm^-2 at 650 °C under ambient pressure. The improved electrochemical kinetics is anticipated to be attributed to two reasons: doping of ions (Ag⁺) in the A-site of perovskite and in situ exsolved silver nanoparticles (Ag NPs) along the edge and on the surface of BCFNs improving the mobile charge and electrical properties of the material. The remaining Ag⁺ in the A-site induced the electron redistribution, whereas the Ag NPs were found to increase the electrochemically active sites and enable the formation of a triple-phase boundary. These explanations were confirmed by the density functional theory study, indicating that Ag-doping processes lead to a decrease in the formation energy of oxygen vacancies from 1.72 to 1.42 eV upon the partial substitution of Ba²⁺ by Ag⁺ cations.

Bioinspired Biomaterials with a Brick-and-Mortar Microstructure Combining Mechanical and Biological Performance

The fabrication of bone regeneration biomaterials, which simultaneously possess superior mechanical performances and excellent bioactivity, remains challenging because these properties are usually mutually exclusive. Herein, inspired by the brick-and-mortar architecture of nacre, lamellar silicate-based bioceramic composites are successfully prepared by constructing orderly layered bioceramics infiltrated with a biomedical resin interlayer via the bidirectional freezing technique. The lamellar composites possess high strength and proper Young's moduli, which match with human cortical bone. Furthermore, the lamellar composites can release bioactive ions with a controlled profile, which significantly enhance the cell proliferation of both rabbit bone mesenchymal stem cells and periodontal ligament cells in vitro. Moreover, with the degradation of silicate bioceramics in vivo, newly formed bone tissue can grow into the materials to present the bioceramic/new bone/resin sandwich-like lamellar microstructure. The silicate-based bioceramic composites with brick-and-mortar architecture represent an excellent biomaterial in combination of superior mechanical performances matching that of human cortical bone, and excellent bioactivity for potential load-bearing bone regeneration.

van der Waals Heterojunction between a Bottom-Up Grown Doped Graphene Quantum Dot and Graphene for Photoelectrochemical Water Splitting

van der Waals heterojunctions (vdWHs) formed between 2D materials have attracted tremendous attention recently due to their extraordinary properties, which cannot be offered by their individual components or other heterojunctions. Intriguing electronic coupling, lowered energy barrier, intimate charge transfer, and efficient exciton separation occurring at the atomically sharp interface promise their applications in catalysis, which, however, are largely unexplored. Herein, we demonstrate a 0D/2D vdWH between 0D graphene quantum dots (GQDs) and 2D pristine graphene sheets, simply prepared by ultrasonication of graphite powder using GQDs as intercalation surfactant. Such an all-carbon Schottky-diode-like 0D/2D vdWH is employed for the emerging photoelectrochemical catalysis (water splitting) with high performance. The demonstrated low-cost and scalable bottom-up growth of heteroatom-doped GQDs will greatly promote their widespread applications. Moreover, the mechanisms underlying GQD growth and heterojunction-mediated catalysis are revealed both experimentally and theoretically.

Lithium silicate-based bioceramics promoting chondrocyte maturation by immunomodulating M2 macrophage polarization

LCS scaffolds promoted chondrocyte maturation by inducing M2 macrophage polarization.

Three-Dimensional-Printed Bioceramic Scaffolds with Osteogenic Activity for Simultaneous Photo/Magnetothermal Therapy of Bone Tumors

For the postoperative treatment of bone cancer, biomaterials should possess an antitumor effect and simultaneous repair ability of bone defects. Compared with single photothermal treatment or magnetothermal treatment, photo/magnetothermal joint treatment represents a more high-efficient strategy to kill tumor cells. In this work, a 3D-printed bioceramic scaffold with a photo/magnetothermal effect was successfully designed and fabricated, which exhibited the function of killing tumor cells and excellent osteogenic bioactivity, via incorporating an Fe element into akermanite (AKT) bioceramics. After doping with ferric elements, the AKT scaffolds possessed significantly enhanced compressive strength and desirable ferromagnetic property. The ferric elements endowed the AKT scaffolds with excellent photo/magnetothermal effects, and hence the scaffolds could efficiently kill tumor cells in vitro under mild laser power density and magnetic field. In addition, the Fe-doped AKT bioceramic scaffolds significantly promoted cell proliferation and osteogenic differentiation of rabbit bone mesenchymal stem cells as compared with the original AKT scaffolds without Fe elements. The results suggest that Fe-doped bioceramic scaffolds with both photo/magnetothermal effect and in vitro osteogenic bioactivity could be a promising biomaterial for the synergistic therapy of bone cancers.

3D Printing of Hot Dog-Like Biomaterials with Hierarchical Architecture and Distinct Bioactivity

Hierarchical structure has exhibited an important influence in the fields of supercapacitors, catalytic applications, and tissue engineering. The hot dog, a popular food, is composed of bread and sausage with special structures. In this study, inspired by the structure of a hot dog, the strategy of combining direct ink writing 3D printing with bidirectional freezing is devised to prepare hot dog-like scaffolds with hierarchical structure. The scaffolds are composed of hollow bioceramic tubes (mimicking the "bread" in hot dogs, pore size: ≈1 mm) embedded by bioceramic rods (mimicking the "sausage" in hot dogs, diameter: ≈500 µm) and the sausage-like bioceramic rods possess uniformly aligned lamellar micropores (lamellar pore size: ≈30 µm). By mimicking the functions of hierarchical structure of bone tissues for transporting and storing nutrients, the prepared hot dog-like scaffolds show excellent properties for loading and releasing drugs and proteins as well as for improving the delivery and differentiation of tissue cells. The in vivo study further demonstrates that both the hierarchical structure itself and the controlled drug delivery in hot dog-like scaffolds significantly contribute to the improved bone-forming bioactivity. This study suggests that the prepared hot dog-like scaffolds are a promising biomaterial for drug delivery, tissue engineering, and regenerative medicine.